camera3.h revision b2bc0e518278b228d8b4c6bd324f04237feb92c3
1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_INCLUDE_CAMERA3_H
18#define ANDROID_INCLUDE_CAMERA3_H
19
20#include <system/camera_metadata.h>
21#include "camera_common.h"
22
23/**
24 * Camera device HAL 3.2 [ CAMERA_DEVICE_API_VERSION_3_2 ]
25 *
26 * This is the current recommended version of the camera device HAL.
27 *
28 * Supports the android.hardware.Camera API, and as of v3.2, the
29 * android.hardware.camera2 API in LIMITED or FULL modes.
30 *
31 * Camera devices that support this version of the HAL must return
32 * CAMERA_DEVICE_API_VERSION_3_2 in camera_device_t.common.version and in
33 * camera_info_t.device_version (from camera_module_t.get_camera_info).
34 *
35 * CAMERA_DEVICE_API_VERSION_3_2:
36 *    Camera modules that may contain version 3.2 devices must implement at
37 *    least version 2.2 of the camera module interface (as defined by
38 *    camera_module_t.common.module_api_version).
39 *
40 * <= CAMERA_DEVICE_API_VERSION_3_1:
41 *    Camera modules that may contain version 3.1 (or 3.0) devices must
42 *    implement at least version 2.0 of the camera module interface
43 *    (as defined by camera_module_t.common.module_api_version).
44 *
45 * See camera_common.h for more versioning details.
46 *
47 * Documentation index:
48 *   S1. Version history
49 *   S2. Startup and operation sequencing
50 *   S3. Operational modes
51 *   S4. 3A modes and state machines
52 *   S5. Cropping
53 *   S6. Error management
54 *   S7. Key Performance Indicator (KPI) glossary
55 *   S8. Sample Use Cases
56 *   S9. Notes on Controls and Metadata
57 */
58
59/**
60 * S1. Version history:
61 *
62 * 1.0: Initial Android camera HAL (Android 4.0) [camera.h]:
63 *
64 *   - Converted from C++ CameraHardwareInterface abstraction layer.
65 *
66 *   - Supports android.hardware.Camera API.
67 *
68 * 2.0: Initial release of expanded-capability HAL (Android 4.2) [camera2.h]:
69 *
70 *   - Sufficient for implementing existing android.hardware.Camera API.
71 *
72 *   - Allows for ZSL queue in camera service layer
73 *
74 *   - Not tested for any new features such manual capture control, Bayer RAW
75 *     capture, reprocessing of RAW data.
76 *
77 * 3.0: First revision of expanded-capability HAL:
78 *
79 *   - Major version change since the ABI is completely different. No change to
80 *     the required hardware capabilities or operational model from 2.0.
81 *
82 *   - Reworked input request and stream queue interfaces: Framework calls into
83 *     HAL with next request and stream buffers already dequeued. Sync framework
84 *     support is included, necessary for efficient implementations.
85 *
86 *   - Moved triggers into requests, most notifications into results.
87 *
88 *   - Consolidated all callbacks into framework into one structure, and all
89 *     setup methods into a single initialize() call.
90 *
91 *   - Made stream configuration into a single call to simplify stream
92 *     management. Bidirectional streams replace STREAM_FROM_STREAM construct.
93 *
94 *   - Limited mode semantics for older/limited hardware devices.
95 *
96 * 3.1: Minor revision of expanded-capability HAL:
97 *
98 *   - configure_streams passes consumer usage flags to the HAL.
99 *
100 *   - flush call to drop all in-flight requests/buffers as fast as possible.
101 *
102 * 3.2: Minor revision of expanded-capability HAL:
103 *
104 *   - Deprecates get_metadata_vendor_tag_ops.  Please use get_vendor_tag_ops
105 *     in camera_common.h instead.
106 *
107 *   - register_stream_buffers deprecated. All gralloc buffers provided
108 *     by framework to HAL in process_capture_request may be new at any time.
109 *
110 *   - add partial result support. process_capture_result may be called
111 *     multiple times with a subset of the available result before the full
112 *     result is available.
113 *
114 *   - add manual template to camera3_request_template. The applications may
115 *     use this template to control the capture settings directly.
116 *
117 *   - Rework the bidirectional and input stream specifications.
118 *
119 *   - change the input buffer return path. The buffer is returned in
120 *     process_capture_result instead of process_capture_request.
121 *
122 */
123
124/**
125 * S2. Startup and general expected operation sequence:
126 *
127 * 1. Framework calls camera_module_t->common.open(), which returns a
128 *    hardware_device_t structure.
129 *
130 * 2. Framework inspects the hardware_device_t->version field, and instantiates
131 *    the appropriate handler for that version of the camera hardware device. In
132 *    case the version is CAMERA_DEVICE_API_VERSION_3_0, the device is cast to
133 *    a camera3_device_t.
134 *
135 * 3. Framework calls camera3_device_t->ops->initialize() with the framework
136 *    callback function pointers. This will only be called this one time after
137 *    open(), before any other functions in the ops structure are called.
138 *
139 * 4. The framework calls camera3_device_t->ops->configure_streams() with a list
140 *    of input/output streams to the HAL device.
141 *
142 * 5. <= CAMERA_DEVICE_API_VERSION_3_1:
143 *
144 *    The framework allocates gralloc buffers and calls
145 *    camera3_device_t->ops->register_stream_buffers() for at least one of the
146 *    output streams listed in configure_streams. The same stream is registered
147 *    only once.
148 *
149 *    >= CAMERA_DEVICE_API_VERSION_3_2:
150 *
151 *    camera3_device_t->ops->register_stream_buffers() is not called and must
152 *    be NULL.
153 *
154 * 6. The framework requests default settings for some number of use cases with
155 *    calls to camera3_device_t->ops->construct_default_request_settings(). This
156 *    may occur any time after step 3.
157 *
158 * 7. The framework constructs and sends the first capture request to the HAL,
159 *    with settings based on one of the sets of default settings, and with at
160 *    least one output stream, which has been registered earlier by the
161 *    framework. This is sent to the HAL with
162 *    camera3_device_t->ops->process_capture_request(). The HAL must block the
163 *    return of this call until it is ready for the next request to be sent.
164 *
165 *    >= CAMERA_DEVICE_API_VERSION_3_2:
166 *
167 *    The buffer_handle_t provided in the camera3_stream_buffer_t array
168 *    in the camera3_capture_request_t may be new and never-before-seen
169 *    by the HAL on any given new request.
170 *
171 * 8. The framework continues to submit requests, and call
172 *    construct_default_request_settings to get default settings buffers for
173 *    other use cases.
174 *
175 *    <= CAMERA_DEVICE_API_VERSION_3_1:
176 *
177 *    The framework may call register_stream_buffers() at this time for
178 *    not-yet-registered streams.
179 *
180 * 9. When the capture of a request begins (sensor starts exposing for the
181 *    capture), the HAL calls camera3_callback_ops_t->notify() with the SHUTTER
182 *    event, including the frame number and the timestamp for start of exposure.
183 *
184 *    <= CAMERA_DEVICE_API_VERSION_3_1:
185 *
186 *    This notify call must be made before the first call to
187 *    process_capture_result() for that frame number.
188 *
189 *    >= CAMERA_DEVICE_API_VERSION_3_2:
190 *
191 *    The camera3_callback_ops_t->notify() call with the SHUTTER event should
192 *    be made as early as possible since the framework will be unable to
193 *    deliver gralloc buffers to the application layer (for that frame) until
194 *    it has a valid timestamp for the start of exposure.
195 *
196 *    Both partial metadata results and the gralloc buffers may be sent to the
197 *    framework at any time before or after the SHUTTER event.
198 *
199 * 10. After some pipeline delay, the HAL begins to return completed captures to
200 *    the framework with camera3_callback_ops_t->process_capture_result(). These
201 *    are returned in the same order as the requests were submitted. Multiple
202 *    requests can be in flight at once, depending on the pipeline depth of the
203 *    camera HAL device.
204 *
205 *    >= CAMERA_DEVICE_API_VERSION_3_2:
206 *
207 *    Once a buffer is returned by process_capture_result as part of the
208 *    camera3_stream_buffer_t array, and the fence specified by release_fence
209 *    has been signaled (this is a no-op for -1 fences), the ownership of that
210 *    buffer is considered to be transferred back to the framework. After that,
211 *    the HAL must no longer retain that particular buffer, and the
212 *    framework may clean up the memory for it immediately.
213 *
214 *    process_capture_result may be called multiple times for a single frame,
215 *    each time with a new disjoint piece of metadata and/or set of gralloc
216 *    buffers. The framework will accumulate these partial metadata results
217 *    into one result.
218 *
219 *    In particular, it is legal for a process_capture_result to be called
220 *    simultaneously for both a frame N and a frame N+1 as long as the
221 *    above rule holds for gralloc buffers (both input and output).
222 *
223 * 11. After some time, the framework may stop submitting new requests, wait for
224 *    the existing captures to complete (all buffers filled, all results
225 *    returned), and then call configure_streams() again. This resets the camera
226 *    hardware and pipeline for a new set of input/output streams. Some streams
227 *    may be reused from the previous configuration; if these streams' buffers
228 *    had already been registered with the HAL, they will not be registered
229 *    again. The framework then continues from step 7, if at least one
230 *    registered output stream remains (otherwise, step 5 is required first).
231 *
232 * 12. Alternatively, the framework may call camera3_device_t->common->close()
233 *    to end the camera session. This may be called at any time when no other
234 *    calls from the framework are active, although the call may block until all
235 *    in-flight captures have completed (all results returned, all buffers
236 *    filled). After the close call returns, no more calls to the
237 *    camera3_callback_ops_t functions are allowed from the HAL. Once the
238 *    close() call is underway, the framework may not call any other HAL device
239 *    functions.
240 *
241 * 13. In case of an error or other asynchronous event, the HAL must call
242 *    camera3_callback_ops_t->notify() with the appropriate error/event
243 *    message. After returning from a fatal device-wide error notification, the
244 *    HAL should act as if close() had been called on it. However, the HAL must
245 *    either cancel or complete all outstanding captures before calling
246 *    notify(), so that once notify() is called with a fatal error, the
247 *    framework will not receive further callbacks from the device. Methods
248 *    besides close() should return -ENODEV or NULL after the notify() method
249 *    returns from a fatal error message.
250 */
251
252/**
253 * S3. Operational modes:
254 *
255 * The camera 3 HAL device can implement one of two possible operational modes;
256 * limited and full. Full support is expected from new higher-end
257 * devices. Limited mode has hardware requirements roughly in line with those
258 * for a camera HAL device v1 implementation, and is expected from older or
259 * inexpensive devices. Full is a strict superset of limited, and they share the
260 * same essential operational flow, as documented above.
261 *
262 * The HAL must indicate its level of support with the
263 * android.info.supportedHardwareLevel static metadata entry, with 0 indicating
264 * limited mode, and 1 indicating full mode support.
265 *
266 * Roughly speaking, limited-mode devices do not allow for application control
267 * of capture settings (3A control only), high-rate capture of high-resolution
268 * images, raw sensor readout, or support for YUV output streams above maximum
269 * recording resolution (JPEG only for large images).
270 *
271 * ** Details of limited mode behavior:
272 *
273 * - Limited-mode devices do not need to implement accurate synchronization
274 *   between capture request settings and the actual image data
275 *   captured. Instead, changes to settings may take effect some time in the
276 *   future, and possibly not for the same output frame for each settings
277 *   entry. Rapid changes in settings may result in some settings never being
278 *   used for a capture. However, captures that include high-resolution output
279 *   buffers ( > 1080p ) have to use the settings as specified (but see below
280 *   for processing rate).
281 *
282 * - Limited-mode devices do not need to support most of the
283 *   settings/result/static info metadata. Specifically, only the following settings
284 *   are expected to be consumed or produced by a limited-mode HAL device:
285 *
286 *   android.control.aeAntibandingMode (controls and dynamic)
287 *   android.control.aeExposureCompensation (controls and dynamic)
288 *   android.control.aeLock (controls and dynamic)
289 *   android.control.aeMode (controls and dynamic)
290 *   android.control.aeRegions (controls and dynamic)
291 *   android.control.aeTargetFpsRange (controls and dynamic)
292 *   android.control.aePrecaptureTrigger (controls and dynamic)
293 *   android.control.afMode (controls and dynamic)
294 *   android.control.afRegions (controls and dynamic)
295 *   android.control.awbLock (controls and dynamic)
296 *   android.control.awbMode (controls and dynamic)
297 *   android.control.awbRegions (controls and dynamic)
298 *   android.control.captureIntent (controls and dynamic)
299 *   android.control.effectMode (controls and dynamic)
300 *   android.control.mode (controls and dynamic)
301 *   android.control.sceneMode (controls and dynamic)
302 *   android.control.videoStabilizationMode (controls and dynamic)
303 *   android.control.aeAvailableAntibandingModes (static)
304 *   android.control.aeAvailableModes (static)
305 *   android.control.aeAvailableTargetFpsRanges (static)
306 *   android.control.aeCompensationRange (static)
307 *   android.control.aeCompensationStep (static)
308 *   android.control.afAvailableModes (static)
309 *   android.control.availableEffects (static)
310 *   android.control.availableSceneModes (static)
311 *   android.control.availableVideoStabilizationModes (static)
312 *   android.control.awbAvailableModes (static)
313 *   android.control.maxRegions (static)
314 *   android.control.sceneModeOverrides (static)
315 *   android.control.aeState (dynamic)
316 *   android.control.afState (dynamic)
317 *   android.control.awbState (dynamic)
318 *
319 *   android.flash.mode (controls and dynamic)
320 *   android.flash.info.available (static)
321 *
322 *   android.info.supportedHardwareLevel (static)
323 *
324 *   android.jpeg.gpsCoordinates (controls and dynamic)
325 *   android.jpeg.gpsProcessingMethod (controls and dynamic)
326 *   android.jpeg.gpsTimestamp (controls and dynamic)
327 *   android.jpeg.orientation (controls and dynamic)
328 *   android.jpeg.quality (controls and dynamic)
329 *   android.jpeg.thumbnailQuality (controls and dynamic)
330 *   android.jpeg.thumbnailSize (controls and dynamic)
331 *   android.jpeg.availableThumbnailSizes (static)
332 *   android.jpeg.maxSize (static)
333 *
334 *   android.lens.info.minimumFocusDistance (static)
335 *
336 *   android.request.id (controls and dynamic)
337 *
338 *   android.scaler.cropRegion (controls and dynamic)
339 *   android.scaler.availableStreamConfigurations (static)
340 *   android.scaler.availableMinFrameDurations (static)
341 *   android.scaler.availableStallDurations (static)
342 *   android.scaler.availableMaxDigitalZoom (static)
343 *   android.scaler.maxDigitalZoom (static)
344 *   android.scaler.croppingType (static)
345 *
346 *   android.sensor.orientation (static)
347 *   android.sensor.timestamp (dynamic)
348 *
349 *   android.statistics.faceDetectMode (controls and dynamic)
350 *   android.statistics.info.availableFaceDetectModes (static)
351 *   android.statistics.faceIds (dynamic)
352 *   android.statistics.faceLandmarks (dynamic)
353 *   android.statistics.faceRectangles (dynamic)
354 *   android.statistics.faceScores (dynamic)
355 *
356 *   android.sync.frameNumber (dynamic)
357 *   android.sync.maxLatency (static)
358 *
359 * - Captures in limited mode that include high-resolution (> 1080p) output
360 *   buffers may block in process_capture_request() until all the output buffers
361 *   have been filled. A full-mode HAL device must process sequences of
362 *   high-resolution requests at the rate indicated in the static metadata for
363 *   that pixel format. The HAL must still call process_capture_result() to
364 *   provide the output; the framework must simply be prepared for
365 *   process_capture_request() to block until after process_capture_result() for
366 *   that request completes for high-resolution captures for limited-mode
367 *   devices.
368 *
369 * - Full-mode devices must support below additional capabilities:
370 *   - 30fps at maximum resolution is preferred, more than 20fps is required.
371 *   - Per frame control (android.sync.maxLatency == PER_FRAME_CONTROL).
372 *   - Sensor manual control metadata. See MANUAL_SENSOR defined in
373 *     android.request.availableCapabilities.
374 *   - Post-processing manual control metadata. See MANUAL_POST_PROCESSING defined
375 *     in android.request.availableCapabilities.
376 *
377 */
378
379/**
380 * S4. 3A modes and state machines:
381 *
382 * While the actual 3A algorithms are up to the HAL implementation, a high-level
383 * state machine description is defined by the HAL interface, to allow the HAL
384 * device and the framework to communicate about the current state of 3A, and to
385 * trigger 3A events.
386 *
387 * When the device is opened, all the individual 3A states must be
388 * STATE_INACTIVE. Stream configuration does not reset 3A. For example, locked
389 * focus must be maintained across the configure() call.
390 *
391 * Triggering a 3A action involves simply setting the relevant trigger entry in
392 * the settings for the next request to indicate start of trigger. For example,
393 * the trigger for starting an autofocus scan is setting the entry
394 * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTROL_AF_TRIGGER_START for one
395 * request, and cancelling an autofocus scan is triggered by setting
396 * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTRL_AF_TRIGGER_CANCEL. Otherwise,
397 * the entry will not exist, or be set to ANDROID_CONTROL_AF_TRIGGER_IDLE. Each
398 * request with a trigger entry set to a non-IDLE value will be treated as an
399 * independent triggering event.
400 *
401 * At the top level, 3A is controlled by the ANDROID_CONTROL_MODE setting, which
402 * selects between no 3A (ANDROID_CONTROL_MODE_OFF), normal AUTO mode
403 * (ANDROID_CONTROL_MODE_AUTO), and using the scene mode setting
404 * (ANDROID_CONTROL_USE_SCENE_MODE).
405 *
406 * - In OFF mode, each of the individual AE/AF/AWB modes are effectively OFF,
407 *   and none of the capture controls may be overridden by the 3A routines.
408 *
409 * - In AUTO mode, Auto-focus, auto-exposure, and auto-whitebalance all run
410 *   their own independent algorithms, and have their own mode, state, and
411 *   trigger metadata entries, as listed in the next section.
412 *
413 * - In USE_SCENE_MODE, the value of the ANDROID_CONTROL_SCENE_MODE entry must
414 *   be used to determine the behavior of 3A routines. In SCENE_MODEs other than
415 *   FACE_PRIORITY, the HAL must override the values of
416 *   ANDROId_CONTROL_AE/AWB/AF_MODE to be the mode it prefers for the selected
417 *   SCENE_MODE. For example, the HAL may prefer SCENE_MODE_NIGHT to use
418 *   CONTINUOUS_FOCUS AF mode. Any user selection of AE/AWB/AF_MODE when scene
419 *   must be ignored for these scene modes.
420 *
421 * - For SCENE_MODE_FACE_PRIORITY, the AE/AWB/AF_MODE controls work as in
422 *   ANDROID_CONTROL_MODE_AUTO, but the 3A routines must bias toward metering
423 *   and focusing on any detected faces in the scene.
424 *
425 * S4.1. Auto-focus settings and result entries:
426 *
427 *  Main metadata entries:
428 *
429 *   ANDROID_CONTROL_AF_MODE: Control for selecting the current autofocus
430 *      mode. Set by the framework in the request settings.
431 *
432 *     AF_MODE_OFF: AF is disabled; the framework/app directly controls lens
433 *         position.
434 *
435 *     AF_MODE_AUTO: Single-sweep autofocus. No lens movement unless AF is
436 *         triggered.
437 *
438 *     AF_MODE_MACRO: Single-sweep up-close autofocus. No lens movement unless
439 *         AF is triggered.
440 *
441 *     AF_MODE_CONTINUOUS_VIDEO: Smooth continuous focusing, for recording
442 *         video. Triggering immediately locks focus in current
443 *         position. Canceling resumes cotinuous focusing.
444 *
445 *     AF_MODE_CONTINUOUS_PICTURE: Fast continuous focusing, for
446 *        zero-shutter-lag still capture. Triggering locks focus once currently
447 *        active sweep concludes. Canceling resumes continuous focusing.
448 *
449 *     AF_MODE_EDOF: Advanced extended depth of field focusing. There is no
450 *        autofocus scan, so triggering one or canceling one has no effect.
451 *        Images are focused automatically by the HAL.
452 *
453 *   ANDROID_CONTROL_AF_STATE: Dynamic metadata describing the current AF
454 *       algorithm state, reported by the HAL in the result metadata.
455 *
456 *     AF_STATE_INACTIVE: No focusing has been done, or algorithm was
457 *        reset. Lens is not moving. Always the state for MODE_OFF or MODE_EDOF.
458 *        When the device is opened, it must start in this state.
459 *
460 *     AF_STATE_PASSIVE_SCAN: A continuous focus algorithm is currently scanning
461 *        for good focus. The lens is moving.
462 *
463 *     AF_STATE_PASSIVE_FOCUSED: A continuous focus algorithm believes it is
464 *        well focused. The lens is not moving. The HAL may spontaneously leave
465 *        this state.
466 *
467 *     AF_STATE_PASSIVE_UNFOCUSED: A continuous focus algorithm believes it is
468 *        not well focused. The lens is not moving. The HAL may spontaneously
469 *        leave this state.
470 *
471 *     AF_STATE_ACTIVE_SCAN: A scan triggered by the user is underway.
472 *
473 *     AF_STATE_FOCUSED_LOCKED: The AF algorithm believes it is focused. The
474 *        lens is not moving.
475 *
476 *     AF_STATE_NOT_FOCUSED_LOCKED: The AF algorithm has been unable to
477 *        focus. The lens is not moving.
478 *
479 *   ANDROID_CONTROL_AF_TRIGGER: Control for starting an autofocus scan, the
480 *       meaning of which is mode- and state- dependent. Set by the framework in
481 *       the request settings.
482 *
483 *     AF_TRIGGER_IDLE: No current trigger.
484 *
485 *     AF_TRIGGER_START: Trigger start of AF scan. Effect is mode and state
486 *         dependent.
487 *
488 *     AF_TRIGGER_CANCEL: Cancel current AF scan if any, and reset algorithm to
489 *         default.
490 *
491 *  Additional metadata entries:
492 *
493 *   ANDROID_CONTROL_AF_REGIONS: Control for selecting the regions of the FOV
494 *       that should be used to determine good focus. This applies to all AF
495 *       modes that scan for focus. Set by the framework in the request
496 *       settings.
497 *
498 * S4.2. Auto-exposure settings and result entries:
499 *
500 *  Main metadata entries:
501 *
502 *   ANDROID_CONTROL_AE_MODE: Control for selecting the current auto-exposure
503 *       mode. Set by the framework in the request settings.
504 *
505 *     AE_MODE_OFF: Autoexposure is disabled; the user controls exposure, gain,
506 *         frame duration, and flash.
507 *
508 *     AE_MODE_ON: Standard autoexposure, with flash control disabled. User may
509 *         set flash to fire or to torch mode.
510 *
511 *     AE_MODE_ON_AUTO_FLASH: Standard autoexposure, with flash on at HAL's
512 *         discretion for precapture and still capture. User control of flash
513 *         disabled.
514 *
515 *     AE_MODE_ON_ALWAYS_FLASH: Standard autoexposure, with flash always fired
516 *         for capture, and at HAL's discretion for precapture.. User control of
517 *         flash disabled.
518 *
519 *     AE_MODE_ON_AUTO_FLASH_REDEYE: Standard autoexposure, with flash on at
520 *         HAL's discretion for precapture and still capture. Use a flash burst
521 *         at end of precapture sequence to reduce redeye in the final
522 *         picture. User control of flash disabled.
523 *
524 *   ANDROID_CONTROL_AE_STATE: Dynamic metadata describing the current AE
525 *       algorithm state, reported by the HAL in the result metadata.
526 *
527 *     AE_STATE_INACTIVE: Initial AE state after mode switch. When the device is
528 *         opened, it must start in this state.
529 *
530 *     AE_STATE_SEARCHING: AE is not converged to a good value, and is adjusting
531 *         exposure parameters.
532 *
533 *     AE_STATE_CONVERGED: AE has found good exposure values for the current
534 *         scene, and the exposure parameters are not changing. HAL may
535 *         spontaneously leave this state to search for better solution.
536 *
537 *     AE_STATE_LOCKED: AE has been locked with the AE_LOCK control. Exposure
538 *         values are not changing.
539 *
540 *     AE_STATE_FLASH_REQUIRED: The HAL has converged exposure, but believes
541 *         flash is required for a sufficiently bright picture. Used for
542 *         determining if a zero-shutter-lag frame can be used.
543 *
544 *     AE_STATE_PRECAPTURE: The HAL is in the middle of a precapture
545 *         sequence. Depending on AE mode, this mode may involve firing the
546 *         flash for metering, or a burst of flash pulses for redeye reduction.
547 *
548 *   ANDROID_CONTROL_AE_PRECAPTURE_TRIGGER: Control for starting a metering
549 *       sequence before capturing a high-quality image. Set by the framework in
550 *       the request settings.
551 *
552 *      PRECAPTURE_TRIGGER_IDLE: No current trigger.
553 *
554 *      PRECAPTURE_TRIGGER_START: Start a precapture sequence. The HAL should
555 *         use the subsequent requests to measure good exposure/white balance
556 *         for an upcoming high-resolution capture.
557 *
558 *  Additional metadata entries:
559 *
560 *   ANDROID_CONTROL_AE_LOCK: Control for locking AE controls to their current
561 *       values
562 *
563 *   ANDROID_CONTROL_AE_EXPOSURE_COMPENSATION: Control for adjusting AE
564 *       algorithm target brightness point.
565 *
566 *   ANDROID_CONTROL_AE_TARGET_FPS_RANGE: Control for selecting the target frame
567 *       rate range for the AE algorithm. The AE routine cannot change the frame
568 *       rate to be outside these bounds.
569 *
570 *   ANDROID_CONTROL_AE_REGIONS: Control for selecting the regions of the FOV
571 *       that should be used to determine good exposure levels. This applies to
572 *       all AE modes besides OFF.
573 *
574 * S4.3. Auto-whitebalance settings and result entries:
575 *
576 *  Main metadata entries:
577 *
578 *   ANDROID_CONTROL_AWB_MODE: Control for selecting the current white-balance
579 *       mode.
580 *
581 *     AWB_MODE_OFF: Auto-whitebalance is disabled. User controls color matrix.
582 *
583 *     AWB_MODE_AUTO: Automatic white balance is enabled; 3A controls color
584 *        transform, possibly using more complex transforms than a simple
585 *        matrix.
586 *
587 *     AWB_MODE_INCANDESCENT: Fixed white balance settings good for indoor
588 *        incandescent (tungsten) lighting, roughly 2700K.
589 *
590 *     AWB_MODE_FLUORESCENT: Fixed white balance settings good for fluorescent
591 *        lighting, roughly 5000K.
592 *
593 *     AWB_MODE_WARM_FLUORESCENT: Fixed white balance settings good for
594 *        fluorescent lighting, roughly 3000K.
595 *
596 *     AWB_MODE_DAYLIGHT: Fixed white balance settings good for daylight,
597 *        roughly 5500K.
598 *
599 *     AWB_MODE_CLOUDY_DAYLIGHT: Fixed white balance settings good for clouded
600 *        daylight, roughly 6500K.
601 *
602 *     AWB_MODE_TWILIGHT: Fixed white balance settings good for
603 *        near-sunset/sunrise, roughly 15000K.
604 *
605 *     AWB_MODE_SHADE: Fixed white balance settings good for areas indirectly
606 *        lit by the sun, roughly 7500K.
607 *
608 *   ANDROID_CONTROL_AWB_STATE: Dynamic metadata describing the current AWB
609 *       algorithm state, reported by the HAL in the result metadata.
610 *
611 *     AWB_STATE_INACTIVE: Initial AWB state after mode switch. When the device
612 *         is opened, it must start in this state.
613 *
614 *     AWB_STATE_SEARCHING: AWB is not converged to a good value, and is
615 *         changing color adjustment parameters.
616 *
617 *     AWB_STATE_CONVERGED: AWB has found good color adjustment values for the
618 *         current scene, and the parameters are not changing. HAL may
619 *         spontaneously leave this state to search for better solution.
620 *
621 *     AWB_STATE_LOCKED: AWB has been locked with the AWB_LOCK control. Color
622 *         adjustment values are not changing.
623 *
624 *  Additional metadata entries:
625 *
626 *   ANDROID_CONTROL_AWB_LOCK: Control for locking AWB color adjustments to
627 *       their current values.
628 *
629 *   ANDROID_CONTROL_AWB_REGIONS: Control for selecting the regions of the FOV
630 *       that should be used to determine good color balance. This applies only
631 *       to auto-WB mode.
632 *
633 * S4.4. General state machine transition notes
634 *
635 *   Switching between AF, AE, or AWB modes always resets the algorithm's state
636 *   to INACTIVE.  Similarly, switching between CONTROL_MODE or
637 *   CONTROL_SCENE_MODE if CONTROL_MODE == USE_SCENE_MODE resets all the
638 *   algorithm states to INACTIVE.
639 *
640 *   The tables below are per-mode.
641 *
642 * S4.5. AF state machines
643 *
644 *                       when enabling AF or changing AF mode
645 *| state              | trans. cause  | new state          | notes            |
646 *+--------------------+---------------+--------------------+------------------+
647 *| Any                | AF mode change| INACTIVE           |                  |
648 *+--------------------+---------------+--------------------+------------------+
649 *
650 *                            mode = AF_MODE_OFF or AF_MODE_EDOF
651 *| state              | trans. cause  | new state          | notes            |
652 *+--------------------+---------------+--------------------+------------------+
653 *| INACTIVE           |               | INACTIVE           | Never changes    |
654 *+--------------------+---------------+--------------------+------------------+
655 *
656 *                            mode = AF_MODE_AUTO or AF_MODE_MACRO
657 *| state              | trans. cause  | new state          | notes            |
658 *+--------------------+---------------+--------------------+------------------+
659 *| INACTIVE           | AF_TRIGGER    | ACTIVE_SCAN        | Start AF sweep   |
660 *|                    |               |                    | Lens now moving  |
661 *+--------------------+---------------+--------------------+------------------+
662 *| ACTIVE_SCAN        | AF sweep done | FOCUSED_LOCKED     | If AF successful |
663 *|                    |               |                    | Lens now locked  |
664 *+--------------------+---------------+--------------------+------------------+
665 *| ACTIVE_SCAN        | AF sweep done | NOT_FOCUSED_LOCKED | If AF successful |
666 *|                    |               |                    | Lens now locked  |
667 *+--------------------+---------------+--------------------+------------------+
668 *| ACTIVE_SCAN        | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
669 *|                    |               |                    | Lens now locked  |
670 *+--------------------+---------------+--------------------+------------------+
671 *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
672 *+--------------------+---------------+--------------------+------------------+
673 *| FOCUSED_LOCKED     | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
674 *|                    |               |                    | Lens now moving  |
675 *+--------------------+---------------+--------------------+------------------+
676 *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
677 *+--------------------+---------------+--------------------+------------------+
678 *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
679 *|                    |               |                    | Lens now moving  |
680 *+--------------------+---------------+--------------------+------------------+
681 *| All states         | mode change   | INACTIVE           |                  |
682 *+--------------------+---------------+--------------------+------------------+
683 *
684 *                            mode = AF_MODE_CONTINUOUS_VIDEO
685 *| state              | trans. cause  | new state          | notes            |
686 *+--------------------+---------------+--------------------+------------------+
687 *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
688 *|                    | new scan      |                    | Lens now moving  |
689 *+--------------------+---------------+--------------------+------------------+
690 *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
691 *|                    |               |                    | Lens now locked  |
692 *+--------------------+---------------+--------------------+------------------+
693 *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
694 *|                    | current scan  |                    | Lens now locked  |
695 *+--------------------+---------------+--------------------+------------------+
696 *| PASSIVE_SCAN       | HAL fails     | PASSIVE_UNFOCUSED  | End AF scan      |
697 *|                    | current scan  |                    | Lens now locked  |
698 *+--------------------+---------------+--------------------+------------------+
699 *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
700 *|                    |               |                    | if focus is good |
701 *|                    |               |                    | Lens now locked  |
702 *+--------------------+---------------+--------------------+------------------+
703 *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
704 *|                    |               |                    | if focus is bad  |
705 *|                    |               |                    | Lens now locked  |
706 *+--------------------+---------------+--------------------+------------------+
707 *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
708 *|                    |               |                    | position         |
709 *|                    |               |                    | Lens now locked  |
710 *+--------------------+---------------+--------------------+------------------+
711 *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
712 *|                    | new scan      |                    | Lens now moving  |
713 *+--------------------+---------------+--------------------+------------------+
714 *| PASSIVE_UNFOCUSED  | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
715 *|                    | new scan      |                    | Lens now moving  |
716 *+--------------------+---------------+--------------------+------------------+
717 *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
718 *|                    |               |                    | Lens now locked  |
719 *+--------------------+---------------+--------------------+------------------+
720 *| PASSIVE_UNFOCUSED  | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
721 *|                    |               |                    | Lens now locked  |
722 *+--------------------+---------------+--------------------+------------------+
723 *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
724 *+--------------------+---------------+--------------------+------------------+
725 *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
726 *+--------------------+---------------+--------------------+------------------+
727 *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
728 *+--------------------+---------------+--------------------+------------------+
729 *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
730 *+--------------------+---------------+--------------------+------------------+
731 *
732 *                            mode = AF_MODE_CONTINUOUS_PICTURE
733 *| state              | trans. cause  | new state          | notes            |
734 *+--------------------+---------------+--------------------+------------------+
735 *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
736 *|                    | new scan      |                    | Lens now moving  |
737 *+--------------------+---------------+--------------------+------------------+
738 *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
739 *|                    |               |                    | Lens now locked  |
740 *+--------------------+---------------+--------------------+------------------+
741 *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
742 *|                    | current scan  |                    | Lens now locked  |
743 *+--------------------+---------------+--------------------+------------------+
744 *| PASSIVE_SCAN       | HAL fails     | PASSIVE_UNFOCUSED  | End AF scan      |
745 *|                    | current scan  |                    | Lens now locked  |
746 *+--------------------+---------------+--------------------+------------------+
747 *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Eventual trans.  |
748 *|                    |               |                    | once focus good  |
749 *|                    |               |                    | Lens now locked  |
750 *+--------------------+---------------+--------------------+------------------+
751 *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Eventual trans.  |
752 *|                    |               |                    | if cannot focus  |
753 *|                    |               |                    | Lens now locked  |
754 *+--------------------+---------------+--------------------+------------------+
755 *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
756 *|                    |               |                    | position         |
757 *|                    |               |                    | Lens now locked  |
758 *+--------------------+---------------+--------------------+------------------+
759 *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
760 *|                    | new scan      |                    | Lens now moving  |
761 *+--------------------+---------------+--------------------+------------------+
762 *| PASSIVE_UNFOCUSED  | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
763 *|                    | new scan      |                    | Lens now moving  |
764 *+--------------------+---------------+--------------------+------------------+
765 *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
766 *|                    |               |                    | Lens now locked  |
767 *+--------------------+---------------+--------------------+------------------+
768 *| PASSIVE_UNFOCUSED  | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
769 *|                    |               |                    | Lens now locked  |
770 *+--------------------+---------------+--------------------+------------------+
771 *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
772 *+--------------------+---------------+--------------------+------------------+
773 *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
774 *+--------------------+---------------+--------------------+------------------+
775 *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
776 *+--------------------+---------------+--------------------+------------------+
777 *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
778 *+--------------------+---------------+--------------------+------------------+
779 *
780 * S4.6. AE and AWB state machines
781 *
782 *   The AE and AWB state machines are mostly identical. AE has additional
783 *   FLASH_REQUIRED and PRECAPTURE states. So rows below that refer to those two
784 *   states should be ignored for the AWB state machine.
785 *
786 *                  when enabling AE/AWB or changing AE/AWB mode
787 *| state              | trans. cause  | new state          | notes            |
788 *+--------------------+---------------+--------------------+------------------+
789 *| Any                |  mode change  | INACTIVE           |                  |
790 *+--------------------+---------------+--------------------+------------------+
791 *
792 *                            mode = AE_MODE_OFF / AWB mode not AUTO
793 *| state              | trans. cause  | new state          | notes            |
794 *+--------------------+---------------+--------------------+------------------+
795 *| INACTIVE           |               | INACTIVE           | AE/AWB disabled  |
796 *+--------------------+---------------+--------------------+------------------+
797 *
798 *                            mode = AE_MODE_ON_* / AWB_MODE_AUTO
799 *| state              | trans. cause  | new state          | notes            |
800 *+--------------------+---------------+--------------------+------------------+
801 *| INACTIVE           | HAL initiates | SEARCHING          |                  |
802 *|                    | AE/AWB scan   |                    |                  |
803 *+--------------------+---------------+--------------------+------------------+
804 *| INACTIVE           | AE/AWB_LOCK   | LOCKED             | values locked    |
805 *|                    | on            |                    |                  |
806 *+--------------------+---------------+--------------------+------------------+
807 *| SEARCHING          | HAL finishes  | CONVERGED          | good values, not |
808 *|                    | AE/AWB scan   |                    | changing         |
809 *+--------------------+---------------+--------------------+------------------+
810 *| SEARCHING          | HAL finishes  | FLASH_REQUIRED     | converged but too|
811 *|                    | AE scan       |                    | dark w/o flash   |
812 *+--------------------+---------------+--------------------+------------------+
813 *| SEARCHING          | AE/AWB_LOCK   | LOCKED             | values locked    |
814 *|                    | on            |                    |                  |
815 *+--------------------+---------------+--------------------+------------------+
816 *| CONVERGED          | HAL initiates | SEARCHING          | values locked    |
817 *|                    | AE/AWB scan   |                    |                  |
818 *+--------------------+---------------+--------------------+------------------+
819 *| CONVERGED          | AE/AWB_LOCK   | LOCKED             | values locked    |
820 *|                    | on            |                    |                  |
821 *+--------------------+---------------+--------------------+------------------+
822 *| FLASH_REQUIRED     | HAL initiates | SEARCHING          | values locked    |
823 *|                    | AE/AWB scan   |                    |                  |
824 *+--------------------+---------------+--------------------+------------------+
825 *| FLASH_REQUIRED     | AE/AWB_LOCK   | LOCKED             | values locked    |
826 *|                    | on            |                    |                  |
827 *+--------------------+---------------+--------------------+------------------+
828 *| LOCKED             | AE/AWB_LOCK   | SEARCHING          | values not good  |
829 *|                    | off           |                    | after unlock     |
830 *+--------------------+---------------+--------------------+------------------+
831 *| LOCKED             | AE/AWB_LOCK   | CONVERGED          | values good      |
832 *|                    | off           |                    | after unlock     |
833 *+--------------------+---------------+--------------------+------------------+
834 *| LOCKED             | AE_LOCK       | FLASH_REQUIRED     | exposure good,   |
835 *|                    | off           |                    | but too dark     |
836 *+--------------------+---------------+--------------------+------------------+
837 *| All AE states      | PRECAPTURE_   | PRECAPTURE         | Start precapture |
838 *|                    | START         |                    | sequence         |
839 *+--------------------+---------------+--------------------+------------------+
840 *| PRECAPTURE         | Sequence done.| CONVERGED          | Ready for high-  |
841 *|                    | AE_LOCK off   |                    | quality capture  |
842 *+--------------------+---------------+--------------------+------------------+
843 *| PRECAPTURE         | Sequence done.| LOCKED             | Ready for high-  |
844 *|                    | AE_LOCK on    |                    | quality capture  |
845 *+--------------------+---------------+--------------------+------------------+
846 *
847 */
848
849/**
850 * S5. Cropping:
851 *
852 * Cropping of the full pixel array (for digital zoom and other use cases where
853 * a smaller FOV is desirable) is communicated through the
854 * ANDROID_SCALER_CROP_REGION setting. This is a per-request setting, and can
855 * change on a per-request basis, which is critical for implementing smooth
856 * digital zoom.
857 *
858 * The region is defined as a rectangle (x, y, width, height), with (x, y)
859 * describing the top-left corner of the rectangle. The rectangle is defined on
860 * the coordinate system of the sensor active pixel array, with (0,0) being the
861 * top-left pixel of the active pixel array. Therefore, the width and height
862 * cannot be larger than the dimensions reported in the
863 * ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY static info field. The minimum allowed
864 * width and height are reported by the HAL through the
865 * ANDROID_SCALER_MAX_DIGITAL_ZOOM static info field, which describes the
866 * maximum supported zoom factor. Therefore, the minimum crop region width and
867 * height are:
868 *
869 * {width, height} =
870 *    { floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[0] /
871 *        ANDROID_SCALER_MAX_DIGITAL_ZOOM),
872 *      floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[1] /
873 *        ANDROID_SCALER_MAX_DIGITAL_ZOOM) }
874 *
875 * If the crop region needs to fulfill specific requirements (for example, it
876 * needs to start on even coordinates, and its width/height needs to be even),
877 * the HAL must do the necessary rounding and write out the final crop region
878 * used in the output result metadata. Similarly, if the HAL implements video
879 * stabilization, it must adjust the result crop region to describe the region
880 * actually included in the output after video stabilization is applied. In
881 * general, a camera-using application must be able to determine the field of
882 * view it is receiving based on the crop region, the dimensions of the image
883 * sensor, and the lens focal length.
884 *
885 * It is assumed that the cropping is applied after raw to other color space
886 * conversion. Raw streams (RAW16 and RAW_OPAQUE) don't have this conversion stage,
887 * and are not croppable. Therefore, the crop region must be ignored by the HAL
888 * for raw streams.
889 *
890 * Since the crop region applies to all non-raw streams, which may have different aspect
891 * ratios than the crop region, the exact sensor region used for each stream may
892 * be smaller than the crop region. Specifically, each stream should maintain
893 * square pixels and its aspect ratio by minimally further cropping the defined
894 * crop region. If the stream's aspect ratio is wider than the crop region, the
895 * stream should be further cropped vertically, and if the stream's aspect ratio
896 * is narrower than the crop region, the stream should be further cropped
897 * horizontally.
898 *
899 * In all cases, the stream crop must be centered within the full crop region,
900 * and each stream is only either cropped horizontally or vertical relative to
901 * the full crop region, never both.
902 *
903 * For example, if two streams are defined, a 640x480 stream (4:3 aspect), and a
904 * 1280x720 stream (16:9 aspect), below demonstrates the expected output regions
905 * for each stream for a few sample crop regions, on a hypothetical 3 MP (2000 x
906 * 1500 pixel array) sensor.
907 *
908 * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
909 *
910 *   640x480 stream crop: (500, 375, 1000, 750) (equal to crop region)
911 *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
912 *
913 * 0                   1000               2000
914 * +---------+---------+---------+----------+
915 * | Active pixel array                     |
916 * |                                        |
917 * |                                        |
918 * +         +-------------------+          + 375
919 * |         |                   |          |
920 * |         O===================O          |
921 * |         I 1280x720 stream   I          |
922 * +         I                   I          + 750
923 * |         I                   I          |
924 * |         O===================O          |
925 * |         |                   |          |
926 * +         +-------------------+          + 1125
927 * |          Crop region, 640x480 stream   |
928 * |                                        |
929 * |                                        |
930 * +---------+---------+---------+----------+ 1500
931 *
932 * Crop region: (500, 375, 1333, 750) (16:9 aspect ratio)
933 *
934 *   640x480 stream crop: (666, 375, 1000, 750) (marked with =)
935 *   1280x720 stream crop: (500, 375, 1333, 750) (equal to crop region)
936 *
937 * 0                   1000               2000
938 * +---------+---------+---------+----------+
939 * | Active pixel array                     |
940 * |                                        |
941 * |                                        |
942 * +         +---O==================O---+   + 375
943 * |         |   I 640x480 stream   I   |   |
944 * |         |   I                  I   |   |
945 * |         |   I                  I   |   |
946 * +         |   I                  I   |   + 750
947 * |         |   I                  I   |   |
948 * |         |   I                  I   |   |
949 * |         |   I                  I   |   |
950 * +         +---O==================O---+   + 1125
951 * |          Crop region, 1280x720 stream  |
952 * |                                        |
953 * |                                        |
954 * +---------+---------+---------+----------+ 1500
955 *
956 * Crop region: (500, 375, 750, 750) (1:1 aspect ratio)
957 *
958 *   640x480 stream crop: (500, 469, 750, 562) (marked with =)
959 *   1280x720 stream crop: (500, 543, 750, 414) (marged with #)
960 *
961 * 0                   1000               2000
962 * +---------+---------+---------+----------+
963 * | Active pixel array                     |
964 * |                                        |
965 * |                                        |
966 * +         +--------------+               + 375
967 * |         O==============O               |
968 * |         ################               |
969 * |         #              #               |
970 * +         #              #               + 750
971 * |         #              #               |
972 * |         ################ 1280x720      |
973 * |         O==============O 640x480       |
974 * +         +--------------+               + 1125
975 * |          Crop region                   |
976 * |                                        |
977 * |                                        |
978 * +---------+---------+---------+----------+ 1500
979 *
980 * And a final example, a 1024x1024 square aspect ratio stream instead of the
981 * 480p stream:
982 *
983 * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
984 *
985 *   1024x1024 stream crop: (625, 375, 750, 750) (marked with #)
986 *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
987 *
988 * 0                   1000               2000
989 * +---------+---------+---------+----------+
990 * | Active pixel array                     |
991 * |                                        |
992 * |              1024x1024 stream          |
993 * +         +--###############--+          + 375
994 * |         |  #             #  |          |
995 * |         O===================O          |
996 * |         I 1280x720 stream   I          |
997 * +         I                   I          + 750
998 * |         I                   I          |
999 * |         O===================O          |
1000 * |         |  #             #  |          |
1001 * +         +--###############--+          + 1125
1002 * |          Crop region                   |
1003 * |                                        |
1004 * |                                        |
1005 * +---------+---------+---------+----------+ 1500
1006 *
1007 */
1008
1009/**
1010 * S6. Error management:
1011 *
1012 * Camera HAL device ops functions that have a return value will all return
1013 * -ENODEV / NULL in case of a serious error. This means the device cannot
1014 * continue operation, and must be closed by the framework. Once this error is
1015 * returned by some method, or if notify() is called with ERROR_DEVICE, only
1016 * the close() method can be called successfully. All other methods will return
1017 * -ENODEV / NULL.
1018 *
1019 * If a device op is called in the wrong sequence, for example if the framework
1020 * calls configure_streams() is called before initialize(), the device must
1021 * return -ENOSYS from the call, and do nothing.
1022 *
1023 * Transient errors in image capture must be reported through notify() as follows:
1024 *
1025 * - The failure of an entire capture to occur must be reported by the HAL by
1026 *   calling notify() with ERROR_REQUEST. Individual errors for the result
1027 *   metadata or the output buffers must not be reported in this case.
1028 *
1029 * - If the metadata for a capture cannot be produced, but some image buffers
1030 *   were filled, the HAL must call notify() with ERROR_RESULT.
1031 *
1032 * - If an output image buffer could not be filled, but either the metadata was
1033 *   produced or some other buffers were filled, the HAL must call notify() with
1034 *   ERROR_BUFFER for each failed buffer.
1035 *
1036 * In each of these transient failure cases, the HAL must still call
1037 * process_capture_result, with valid output and input (if an input buffer was
1038 * submitted) buffer_handle_t. If the result metadata could not be produced, it
1039 * should be NULL. If some buffers could not be filled, they must be returned with
1040 * process_capture_result in the error state, their release fences must be set to
1041 * the acquire fences passed by the framework, or -1 if they have been waited on by
1042 * the HAL already.
1043 *
1044 * Invalid input arguments result in -EINVAL from the appropriate methods. In
1045 * that case, the framework must act as if that call had never been made.
1046 *
1047 */
1048
1049/**
1050 * S7. Key Performance Indicator (KPI) glossary:
1051 *
1052 * This includes some critical definitions that are used by KPI metrics.
1053 *
1054 * Pipeline Latency:
1055 *  For a given capture request, the duration from the framework calling
1056 *  process_capture_request to the HAL sending capture result and all buffers
1057 *  back by process_capture_result call. To make the Pipeline Latency measure
1058 *  independent of frame rate, it is measured by frame count.
1059 *
1060 *  For example, when frame rate is 30 (fps), the frame duration (time interval
1061 *  between adjacent frame capture time) is 33 (ms).
1062 *  If it takes 5 frames for framework to get the result and buffers back for
1063 *  a given request, then the Pipeline Latency is 5 (frames), instead of
1064 *  5 x 33 = 165 (ms).
1065 *
1066 *  The Pipeline Latency is determined by android.request.pipelineDepth and
1067 *  android.request.pipelineMaxDepth, see their definitions for more details.
1068 *
1069 */
1070
1071/**
1072 * S8. Sample Use Cases:
1073 *
1074 * This includes some typical use case examples the camera HAL may support.
1075 *
1076 * S8.1 Zero Shutter Lag (ZSL) with CAMERA3_STREAM_BIDIRECTIONAL stream.
1077 *
1078 *   For this use case, the bidirectional stream will be used by the framework as follows:
1079 *
1080 *   1. The framework includes a buffer from this stream as output buffer in a
1081 *      request as normal.
1082 *
1083 *   2. Once the HAL device returns a filled output buffer to the framework,
1084 *      the framework may do one of two things with the filled buffer:
1085 *
1086 *   2. a. The framework uses the filled data, and returns the now-used buffer
1087 *         to the stream queue for reuse. This behavior exactly matches the
1088 *         OUTPUT type of stream.
1089 *
1090 *   2. b. The framework wants to reprocess the filled data, and uses the
1091 *         buffer as an input buffer for a request. Once the HAL device has
1092 *         used the reprocessing buffer, it then returns it to the
1093 *         framework. The framework then returns the now-used buffer to the
1094 *         stream queue for reuse.
1095 *
1096 *   3. The HAL device will be given the buffer again as an output buffer for
1097 *        a request at some future point.
1098 *
1099 *   For ZSL use case, the pixel format for bidirectional stream will be
1100 *   HAL_PIXEL_FORMAT_RAW_OPAQUE or HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED if it
1101 *   is listed in android.scaler.availableInputOutputFormatsMap. When
1102 *   HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED is used, the gralloc
1103 *   usage flags for the consumer endpoint will be set to GRALLOC_USAGE_HW_CAMERA_ZSL.
1104 *   A configuration stream list that has BIDIRECTIONAL stream used as input, will
1105 *   usually also have a distinct OUTPUT stream to get the reprocessing data. For example,
1106 *   for the ZSL use case, the stream list might be configured with the following:
1107 *
1108 *     - A HAL_PIXEL_FORMAT_RAW_OPAQUE bidirectional stream is used
1109 *       as input.
1110 *     - And a HAL_PIXEL_FORMAT_BLOB (JPEG) output stream.
1111 *
1112 */
1113
1114/**
1115 *   S9. Notes on Controls and Metadata
1116 *
1117 *   This section contains notes about the interpretation and usage of various metadata tags.
1118 *
1119 *   S9.1 HIGH_QUALITY and FAST modes.
1120 *
1121 *   Many camera post-processing blocks may be listed as having HIGH_QUALITY,
1122 *   FAST, and OFF operating modes. These blocks will typically also have an
1123 *   'available modes' tag representing which of these operating modes are
1124 *   available on a given device. The general policy regarding implementing
1125 *   these modes is as follows:
1126 *
1127 *   1. Operating mode controls of hardware blocks that cannot be disabled
1128 *      must not list OFF in their corresponding 'available modes' tags.
1129 *
1130 *   2. OFF will always be included in their corresponding 'available modes'
1131 *      tag if it is possible to disable that hardware block.
1132 *
1133 *   3. FAST must always be included in the 'available modes' tags for all
1134 *      post-processing blocks supported on the device.  If a post-processing
1135 *      block also has a slower and higher quality operating mode that does
1136 *      not meet the framerate requirements for FAST mode, HIGH_QUALITY should
1137 *      be included in the 'available modes' tag to represent this operating
1138 *      mode.
1139 */
1140__BEGIN_DECLS
1141
1142struct camera3_device;
1143
1144/**********************************************************************
1145 *
1146 * Camera3 stream and stream buffer definitions.
1147 *
1148 * These structs and enums define the handles and contents of the input and
1149 * output streams connecting the HAL to various framework and application buffer
1150 * consumers. Each stream is backed by a gralloc buffer queue.
1151 *
1152 */
1153
1154/**
1155 * camera3_stream_type_t:
1156 *
1157 * The type of the camera stream, which defines whether the camera HAL device is
1158 * the producer or the consumer for that stream, and how the buffers of the
1159 * stream relate to the other streams.
1160 */
1161typedef enum camera3_stream_type {
1162    /**
1163     * This stream is an output stream; the camera HAL device will be
1164     * responsible for filling buffers from this stream with newly captured or
1165     * reprocessed image data.
1166     */
1167    CAMERA3_STREAM_OUTPUT = 0,
1168
1169    /**
1170     * This stream is an input stream; the camera HAL device will be responsible
1171     * for reading buffers from this stream and sending them through the camera
1172     * processing pipeline, as if the buffer was a newly captured image from the
1173     * imager.
1174     *
1175     * The pixel format for input stream can be any format reported by
1176     * android.scaler.availableInputOutputFormatsMap. The pixel format of the
1177     * output stream that is used to produce the reprocessing data may be any
1178     * format reported by android.scaler.availableStreamConfigurations. The
1179     * supported input/output stream combinations depends the camera device
1180     * capabilities, see android.scaler.availableInputOutputFormatsMap for
1181     * stream map details.
1182     *
1183     * This kind of stream is generally used to reprocess data into higher
1184     * quality images (that otherwise would cause a frame rate performance
1185     * loss), or to do off-line reprocessing.
1186     *
1187     */
1188    CAMERA3_STREAM_INPUT = 1,
1189
1190    /**
1191     * This stream can be used for input and output. Typically, the stream is
1192     * used as an output stream, but occasionally one already-filled buffer may
1193     * be sent back to the HAL device for reprocessing.
1194     *
1195     * This kind of stream is meant generally for Zero Shutter Lag (ZSL)
1196     * features, where copying the captured image from the output buffer to the
1197     * reprocessing input buffer would be expensive. See S8.1 for more details.
1198     *
1199     * Note that the HAL will always be reprocessing data it produced.
1200     *
1201     */
1202    CAMERA3_STREAM_BIDIRECTIONAL = 2,
1203
1204    /**
1205     * Total number of framework-defined stream types
1206     */
1207    CAMERA3_NUM_STREAM_TYPES
1208
1209} camera3_stream_type_t;
1210
1211/**
1212 * camera3_stream_t:
1213 *
1214 * A handle to a single camera input or output stream. A stream is defined by
1215 * the framework by its buffer resolution and format, and additionally by the
1216 * HAL with the gralloc usage flags and the maximum in-flight buffer count.
1217 *
1218 * The stream structures are owned by the framework, but pointers to a
1219 * camera3_stream passed into the HAL by configure_streams() are valid until the
1220 * end of the first subsequent configure_streams() call that _does not_ include
1221 * that camera3_stream as an argument, or until the end of the close() call.
1222 *
1223 * All camera3_stream framework-controlled members are immutable once the
1224 * camera3_stream is passed into configure_streams().  The HAL may only change
1225 * the HAL-controlled parameters during a configure_streams() call, except for
1226 * the contents of the private pointer.
1227 *
1228 * If a configure_streams() call returns a non-fatal error, all active streams
1229 * remain valid as if configure_streams() had not been called.
1230 *
1231 * The endpoint of the stream is not visible to the camera HAL device.
1232 * In DEVICE_API_VERSION_3_1, this was changed to share consumer usage flags
1233 * on streams where the camera is a producer (OUTPUT and BIDIRECTIONAL stream
1234 * types) see the usage field below.
1235 */
1236typedef struct camera3_stream {
1237
1238    /*****
1239     * Set by framework before configure_streams()
1240     */
1241
1242    /**
1243     * The type of the stream, one of the camera3_stream_type_t values.
1244     */
1245    int stream_type;
1246
1247    /**
1248     * The width in pixels of the buffers in this stream
1249     */
1250    uint32_t width;
1251
1252    /**
1253     * The height in pixels of the buffers in this stream
1254     */
1255    uint32_t height;
1256
1257    /**
1258     * The pixel format for the buffers in this stream. Format is a value from
1259     * the HAL_PIXEL_FORMAT_* list in system/core/include/system/graphics.h, or
1260     * from device-specific headers.
1261     *
1262     * If HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED is used, then the platform
1263     * gralloc module will select a format based on the usage flags provided by
1264     * the camera device and the other endpoint of the stream.
1265     *
1266     * <= CAMERA_DEVICE_API_VERSION_3_1:
1267     *
1268     * The camera HAL device must inspect the buffers handed to it in the
1269     * subsequent register_stream_buffers() call to obtain the
1270     * implementation-specific format details, if necessary.
1271     *
1272     * >= CAMERA_DEVICE_API_VERSION_3_2:
1273     *
1274     * register_stream_buffers() won't be called by the framework, so the HAL
1275     * should configure the ISP and sensor pipeline based purely on the sizes,
1276     * usage flags, and formats for the configured streams.
1277     */
1278    int format;
1279
1280    /*****
1281     * Set by HAL during configure_streams().
1282     */
1283
1284    /**
1285     * The gralloc usage flags for this stream, as needed by the HAL. The usage
1286     * flags are defined in gralloc.h (GRALLOC_USAGE_*), or in device-specific
1287     * headers.
1288     *
1289     * For output streams, these are the HAL's producer usage flags. For input
1290     * streams, these are the HAL's consumer usage flags. The usage flags from
1291     * the producer and the consumer will be combined together and then passed
1292     * to the platform gralloc HAL module for allocating the gralloc buffers for
1293     * each stream.
1294     *
1295     * Version information:
1296     *
1297     * == CAMERA_DEVICE_API_VERSION_3_0:
1298     *
1299     *   No initial value guaranteed when passed via configure_streams().
1300     *   HAL may not use this field as input, and must write over this field
1301     *   with its usage flags.
1302     *
1303     * >= CAMERA_DEVICE_API_VERSION_3_1:
1304     *
1305     *   For stream_type OUTPUT and BIDIRECTIONAL, when passed via
1306     *   configure_streams(), the initial value of this is the consumer's
1307     *   usage flags.  The HAL may use these consumer flags to decide stream
1308     *   configuration.
1309     *   For stream_type INPUT, when passed via configure_streams(), the initial
1310     *   value of this is 0.
1311     *   For all streams passed via configure_streams(), the HAL must write
1312     *   over this field with its usage flags.
1313     */
1314    uint32_t usage;
1315
1316    /**
1317     * The maximum number of buffers the HAL device may need to have dequeued at
1318     * the same time. The HAL device may not have more buffers in-flight from
1319     * this stream than this value.
1320     */
1321    uint32_t max_buffers;
1322
1323    /**
1324     * A handle to HAL-private information for the stream. Will not be inspected
1325     * by the framework code.
1326     */
1327    void *priv;
1328
1329} camera3_stream_t;
1330
1331/**
1332 * camera3_stream_configuration_t:
1333 *
1334 * A structure of stream definitions, used by configure_streams(). This
1335 * structure defines all the output streams and the reprocessing input
1336 * stream for the current camera use case.
1337 */
1338typedef struct camera3_stream_configuration {
1339    /**
1340     * The total number of streams requested by the framework.  This includes
1341     * both input and output streams. The number of streams will be at least 1,
1342     * and there will be at least one output-capable stream.
1343     */
1344    uint32_t num_streams;
1345
1346    /**
1347     * An array of camera stream pointers, defining the input/output
1348     * configuration for the camera HAL device.
1349     *
1350     * At most one input-capable stream may be defined (INPUT or BIDIRECTIONAL)
1351     * in a single configuration.
1352     *
1353     * At least one output-capable stream must be defined (OUTPUT or
1354     * BIDIRECTIONAL).
1355     */
1356    camera3_stream_t **streams;
1357
1358} camera3_stream_configuration_t;
1359
1360/**
1361 * camera3_buffer_status_t:
1362 *
1363 * The current status of a single stream buffer.
1364 */
1365typedef enum camera3_buffer_status {
1366    /**
1367     * The buffer is in a normal state, and can be used after waiting on its
1368     * sync fence.
1369     */
1370    CAMERA3_BUFFER_STATUS_OK = 0,
1371
1372    /**
1373     * The buffer does not contain valid data, and the data in it should not be
1374     * used. The sync fence must still be waited on before reusing the buffer.
1375     */
1376    CAMERA3_BUFFER_STATUS_ERROR = 1
1377
1378} camera3_buffer_status_t;
1379
1380/**
1381 * camera3_stream_buffer_t:
1382 *
1383 * A single buffer from a camera3 stream. It includes a handle to its parent
1384 * stream, the handle to the gralloc buffer itself, and sync fences
1385 *
1386 * The buffer does not specify whether it is to be used for input or output;
1387 * that is determined by its parent stream type and how the buffer is passed to
1388 * the HAL device.
1389 */
1390typedef struct camera3_stream_buffer {
1391    /**
1392     * The handle of the stream this buffer is associated with
1393     */
1394    camera3_stream_t *stream;
1395
1396    /**
1397     * The native handle to the buffer
1398     */
1399    buffer_handle_t *buffer;
1400
1401    /**
1402     * Current state of the buffer, one of the camera3_buffer_status_t
1403     * values. The framework will not pass buffers to the HAL that are in an
1404     * error state. In case a buffer could not be filled by the HAL, it must
1405     * have its status set to CAMERA3_BUFFER_STATUS_ERROR when returned to the
1406     * framework with process_capture_result().
1407     */
1408    int status;
1409
1410    /**
1411     * The acquire sync fence for this buffer. The HAL must wait on this fence
1412     * fd before attempting to read from or write to this buffer.
1413     *
1414     * The framework may be set to -1 to indicate that no waiting is necessary
1415     * for this buffer.
1416     *
1417     * When the HAL returns an output buffer to the framework with
1418     * process_capture_result(), the acquire_fence must be set to -1. If the HAL
1419     * never waits on the acquire_fence due to an error in filling a buffer,
1420     * when calling process_capture_result() the HAL must set the release_fence
1421     * of the buffer to be the acquire_fence passed to it by the framework. This
1422     * will allow the framework to wait on the fence before reusing the buffer.
1423     *
1424     * For input buffers, the HAL must not change the acquire_fence field during
1425     * the process_capture_request() call.
1426     *
1427     * >= CAMERA_DEVICE_API_VERSION_3_2:
1428     *
1429     * When the HAL returns an input buffer to the framework with
1430     * process_capture_result(), the acquire_fence must be set to -1. If the HAL
1431     * never waits on input buffer acquire fence due to an error, the sync
1432     * fences should be handled similarly to the way they are handled for output
1433     * buffers.
1434     */
1435     int acquire_fence;
1436
1437    /**
1438     * The release sync fence for this buffer. The HAL must set this fence when
1439     * returning buffers to the framework, or write -1 to indicate that no
1440     * waiting is required for this buffer.
1441     *
1442     * For the output buffers, the fences must be set in the output_buffers
1443     * array passed to process_capture_result().
1444     *
1445     * <= CAMERA_DEVICE_API_VERSION_3_1:
1446     *
1447     * For the input buffer, the release fence must be set by the
1448     * process_capture_request() call.
1449     *
1450     * >= CAMERA_DEVICE_API_VERSION_3_2:
1451     *
1452     * For the input buffer, the fences must be set in the input_buffer
1453     * passed to process_capture_result().
1454     *
1455     * After signaling the release_fence for this buffer, the HAL
1456     * should not make any further attempts to access this buffer as the
1457     * ownership has been fully transferred back to the framework.
1458     *
1459     * If a fence of -1 was specified then the ownership of this buffer
1460     * is transferred back immediately upon the call of process_capture_result.
1461     */
1462    int release_fence;
1463
1464} camera3_stream_buffer_t;
1465
1466/**
1467 * camera3_stream_buffer_set_t:
1468 *
1469 * The complete set of gralloc buffers for a stream. This structure is given to
1470 * register_stream_buffers() to allow the camera HAL device to register/map/etc
1471 * newly allocated stream buffers.
1472 *
1473 * >= CAMERA_DEVICE_API_VERSION_3_2:
1474 *
1475 * Deprecated (and not used). In particular,
1476 * register_stream_buffers is also deprecated and will never be invoked.
1477 *
1478 */
1479typedef struct camera3_stream_buffer_set {
1480    /**
1481     * The stream handle for the stream these buffers belong to
1482     */
1483    camera3_stream_t *stream;
1484
1485    /**
1486     * The number of buffers in this stream. It is guaranteed to be at least
1487     * stream->max_buffers.
1488     */
1489    uint32_t num_buffers;
1490
1491    /**
1492     * The array of gralloc buffer handles for this stream. If the stream format
1493     * is set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, the camera HAL device
1494     * should inspect the passed-in buffers to determine any platform-private
1495     * pixel format information.
1496     */
1497    buffer_handle_t **buffers;
1498
1499} camera3_stream_buffer_set_t;
1500
1501/**
1502 * camera3_jpeg_blob:
1503 *
1504 * Transport header for compressed JPEG buffers in output streams.
1505 *
1506 * To capture JPEG images, a stream is created using the pixel format
1507 * HAL_PIXEL_FORMAT_BLOB. The buffer size for the stream is calculated by the
1508 * framework, based on the static metadata field android.jpeg.maxSize. Since
1509 * compressed JPEG images are of variable size, the HAL needs to include the
1510 * final size of the compressed image using this structure inside the output
1511 * stream buffer. The JPEG blob ID field must be set to CAMERA3_JPEG_BLOB_ID.
1512 *
1513 * Transport header should be at the end of the JPEG output stream buffer. That
1514 * means the jpeg_blob_id must start at byte[buffer_size -
1515 * sizeof(camera3_jpeg_blob)], where the buffer_size is the size of gralloc buffer.
1516 * Any HAL using this transport header must account for it in android.jpeg.maxSize
1517 * The JPEG data itself starts at the beginning of the buffer and should be
1518 * jpeg_size bytes long.
1519 */
1520typedef struct camera3_jpeg_blob {
1521    uint16_t jpeg_blob_id;
1522    uint32_t jpeg_size;
1523} camera3_jpeg_blob_t;
1524
1525enum {
1526    CAMERA3_JPEG_BLOB_ID = 0x00FF
1527};
1528
1529/**********************************************************************
1530 *
1531 * Message definitions for the HAL notify() callback.
1532 *
1533 * These definitions are used for the HAL notify callback, to signal
1534 * asynchronous events from the HAL device to the Android framework.
1535 *
1536 */
1537
1538/**
1539 * camera3_msg_type:
1540 *
1541 * Indicates the type of message sent, which specifies which member of the
1542 * message union is valid.
1543 *
1544 */
1545typedef enum camera3_msg_type {
1546    /**
1547     * An error has occurred. camera3_notify_msg.message.error contains the
1548     * error information.
1549     */
1550    CAMERA3_MSG_ERROR = 1,
1551
1552    /**
1553     * The exposure of a given request has
1554     * begun. camera3_notify_msg.message.shutter contains the information
1555     * the capture.
1556     */
1557    CAMERA3_MSG_SHUTTER = 2,
1558
1559    /**
1560     * Number of framework message types
1561     */
1562    CAMERA3_NUM_MESSAGES
1563
1564} camera3_msg_type_t;
1565
1566/**
1567 * Defined error codes for CAMERA_MSG_ERROR
1568 */
1569typedef enum camera3_error_msg_code {
1570    /**
1571     * A serious failure occured. No further frames or buffer streams will
1572     * be produced by the device. Device should be treated as closed. The
1573     * client must reopen the device to use it again. The frame_number field
1574     * is unused.
1575     */
1576    CAMERA3_MSG_ERROR_DEVICE = 1,
1577
1578    /**
1579     * An error has occurred in processing a request. No output (metadata or
1580     * buffers) will be produced for this request. The frame_number field
1581     * specifies which request has been dropped. Subsequent requests are
1582     * unaffected, and the device remains operational.
1583     */
1584    CAMERA3_MSG_ERROR_REQUEST = 2,
1585
1586    /**
1587     * An error has occurred in producing an output result metadata buffer
1588     * for a request, but output stream buffers for it will still be
1589     * available. Subsequent requests are unaffected, and the device remains
1590     * operational.  The frame_number field specifies the request for which
1591     * result metadata won't be available.
1592     */
1593    CAMERA3_MSG_ERROR_RESULT = 3,
1594
1595    /**
1596     * An error has occurred in placing an output buffer into a stream for a
1597     * request. The frame metadata and other buffers may still be
1598     * available. Subsequent requests are unaffected, and the device remains
1599     * operational. The frame_number field specifies the request for which the
1600     * buffer was dropped, and error_stream contains a pointer to the stream
1601     * that dropped the frame.u
1602     */
1603    CAMERA3_MSG_ERROR_BUFFER = 4,
1604
1605    /**
1606     * Number of error types
1607     */
1608    CAMERA3_MSG_NUM_ERRORS
1609
1610} camera3_error_msg_code_t;
1611
1612/**
1613 * camera3_error_msg_t:
1614 *
1615 * Message contents for CAMERA3_MSG_ERROR
1616 */
1617typedef struct camera3_error_msg {
1618    /**
1619     * Frame number of the request the error applies to. 0 if the frame number
1620     * isn't applicable to the error.
1621     */
1622    uint32_t frame_number;
1623
1624    /**
1625     * Pointer to the stream that had a failure. NULL if the stream isn't
1626     * applicable to the error.
1627     */
1628    camera3_stream_t *error_stream;
1629
1630    /**
1631     * The code for this error; one of the CAMERA_MSG_ERROR enum values.
1632     */
1633    int error_code;
1634
1635} camera3_error_msg_t;
1636
1637/**
1638 * camera3_shutter_msg_t:
1639 *
1640 * Message contents for CAMERA3_MSG_SHUTTER
1641 */
1642typedef struct camera3_shutter_msg {
1643    /**
1644     * Frame number of the request that has begun exposure
1645     */
1646    uint32_t frame_number;
1647
1648    /**
1649     * Timestamp for the start of capture. This must match the capture result
1650     * metadata's sensor exposure start timestamp.
1651     */
1652    uint64_t timestamp;
1653
1654} camera3_shutter_msg_t;
1655
1656/**
1657 * camera3_notify_msg_t:
1658 *
1659 * The message structure sent to camera3_callback_ops_t.notify()
1660 */
1661typedef struct camera3_notify_msg {
1662
1663    /**
1664     * The message type. One of camera3_notify_msg_type, or a private extension.
1665     */
1666    int type;
1667
1668    union {
1669        /**
1670         * Error message contents. Valid if type is CAMERA3_MSG_ERROR
1671         */
1672        camera3_error_msg_t error;
1673
1674        /**
1675         * Shutter message contents. Valid if type is CAMERA3_MSG_SHUTTER
1676         */
1677        camera3_shutter_msg_t shutter;
1678
1679        /**
1680         * Generic message contents. Used to ensure a minimum size for custom
1681         * message types.
1682         */
1683        uint8_t generic[32];
1684    } message;
1685
1686} camera3_notify_msg_t;
1687
1688/**********************************************************************
1689 *
1690 * Capture request/result definitions for the HAL process_capture_request()
1691 * method, and the process_capture_result() callback.
1692 *
1693 */
1694
1695/**
1696 * camera3_request_template_t:
1697 *
1698 * Available template types for
1699 * camera3_device_ops.construct_default_request_settings()
1700 */
1701typedef enum camera3_request_template {
1702    /**
1703     * Standard camera preview operation with 3A on auto.
1704     */
1705    CAMERA3_TEMPLATE_PREVIEW = 1,
1706
1707    /**
1708     * Standard camera high-quality still capture with 3A and flash on auto.
1709     */
1710    CAMERA3_TEMPLATE_STILL_CAPTURE = 2,
1711
1712    /**
1713     * Standard video recording plus preview with 3A on auto, torch off.
1714     */
1715    CAMERA3_TEMPLATE_VIDEO_RECORD = 3,
1716
1717    /**
1718     * High-quality still capture while recording video. Application will
1719     * include preview, video record, and full-resolution YUV or JPEG streams in
1720     * request. Must not cause stuttering on video stream. 3A on auto.
1721     */
1722    CAMERA3_TEMPLATE_VIDEO_SNAPSHOT = 4,
1723
1724    /**
1725     * Zero-shutter-lag mode. Application will request preview and
1726     * full-resolution data for each frame, and reprocess it to JPEG when a
1727     * still image is requested by user. Settings should provide highest-quality
1728     * full-resolution images without compromising preview frame rate. 3A on
1729     * auto.
1730     */
1731    CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG = 5,
1732
1733    /**
1734     * A basic template for direct application control of capture
1735     * parameters. All automatic control is disabled (auto-exposure, auto-white
1736     * balance, auto-focus), and post-processing parameters are set to preview
1737     * quality. The manual capture parameters (exposure, sensitivity, etc.)
1738     * are set to reasonable defaults, but should be overridden by the
1739     * application depending on the intended use case.
1740     */
1741    CAMERA3_TEMPLATE_MANUAL = 6,
1742
1743    /* Total number of templates */
1744    CAMERA3_TEMPLATE_COUNT,
1745
1746    /**
1747     * First value for vendor-defined request templates
1748     */
1749    CAMERA3_VENDOR_TEMPLATE_START = 0x40000000
1750
1751} camera3_request_template_t;
1752
1753/**
1754 * camera3_capture_request_t:
1755 *
1756 * A single request for image capture/buffer reprocessing, sent to the Camera
1757 * HAL device by the framework in process_capture_request().
1758 *
1759 * The request contains the settings to be used for this capture, and the set of
1760 * output buffers to write the resulting image data in. It may optionally
1761 * contain an input buffer, in which case the request is for reprocessing that
1762 * input buffer instead of capturing a new image with the camera sensor. The
1763 * capture is identified by the frame_number.
1764 *
1765 * In response, the camera HAL device must send a camera3_capture_result
1766 * structure asynchronously to the framework, using the process_capture_result()
1767 * callback.
1768 */
1769typedef struct camera3_capture_request {
1770    /**
1771     * The frame number is an incrementing integer set by the framework to
1772     * uniquely identify this capture. It needs to be returned in the result
1773     * call, and is also used to identify the request in asynchronous
1774     * notifications sent to camera3_callback_ops_t.notify().
1775     */
1776    uint32_t frame_number;
1777
1778    /**
1779     * The settings buffer contains the capture and processing parameters for
1780     * the request. As a special case, a NULL settings buffer indicates that the
1781     * settings are identical to the most-recently submitted capture request. A
1782     * NULL buffer cannot be used as the first submitted request after a
1783     * configure_streams() call.
1784     */
1785    const camera_metadata_t *settings;
1786
1787    /**
1788     * The input stream buffer to use for this request, if any.
1789     *
1790     * If input_buffer is NULL, then the request is for a new capture from the
1791     * imager. If input_buffer is valid, the request is for reprocessing the
1792     * image contained in input_buffer.
1793     *
1794     * In the latter case, the HAL must set the release_fence of the
1795     * input_buffer to a valid sync fence, or to -1 if the HAL does not support
1796     * sync, before process_capture_request() returns.
1797     *
1798     * The HAL is required to wait on the acquire sync fence of the input buffer
1799     * before accessing it.
1800     *
1801     * <= CAMERA_DEVICE_API_VERSION_3_1:
1802     *
1803     * Any input buffer included here will have been registered with the HAL
1804     * through register_stream_buffers() before its inclusion in a request.
1805     *
1806     * >= CAMERA_DEVICE_API_VERSION_3_2:
1807     *
1808     * The buffers will not have been pre-registered with the HAL.
1809     * Subsequent requests may reuse buffers, or provide entirely new buffers.
1810     */
1811    camera3_stream_buffer_t *input_buffer;
1812
1813    /**
1814     * The number of output buffers for this capture request. Must be at least
1815     * 1.
1816     */
1817    uint32_t num_output_buffers;
1818
1819    /**
1820     * An array of num_output_buffers stream buffers, to be filled with image
1821     * data from this capture/reprocess. The HAL must wait on the acquire fences
1822     * of each stream buffer before writing to them.
1823     *
1824     * The HAL takes ownership of the actual buffer_handle_t entries in
1825     * output_buffers; the framework does not access them until they are
1826     * returned in a camera3_capture_result_t.
1827     *
1828     * <= CAMERA_DEVICE_API_VERSION_3_1:
1829     *
1830     * All the buffers included  here will have been registered with the HAL
1831     * through register_stream_buffers() before their inclusion in a request.
1832     *
1833     * >= CAMERA_DEVICE_API_VERSION_3_2:
1834     *
1835     * Any or all of the buffers included here may be brand new in this
1836     * request (having never before seen by the HAL).
1837     */
1838    const camera3_stream_buffer_t *output_buffers;
1839
1840} camera3_capture_request_t;
1841
1842/**
1843 * camera3_capture_result_t:
1844 *
1845 * The result of a single capture/reprocess by the camera HAL device. This is
1846 * sent to the framework asynchronously with process_capture_result(), in
1847 * response to a single capture request sent to the HAL with
1848 * process_capture_request(). Multiple process_capture_result() calls may be
1849 * performed by the HAL for each request.
1850 *
1851 * Each call, all with the same frame
1852 * number, may contain some subset of the output buffers, and/or the result
1853 * metadata. The metadata may only be provided once for a given frame number;
1854 * all other calls must set the result metadata to NULL.
1855 *
1856 * The result structure contains the output metadata from this capture, and the
1857 * set of output buffers that have been/will be filled for this capture. Each
1858 * output buffer may come with a release sync fence that the framework will wait
1859 * on before reading, in case the buffer has not yet been filled by the HAL.
1860 *
1861 * >= CAMERA_DEVICE_API_VERSION_3_2:
1862 *
1863 * The metadata may be provided multiple times for a single frame number. The
1864 * framework will accumulate together the final result set by combining each
1865 * partial result together into the total result set.
1866 *
1867 * If an input buffer is given in a request, the HAL must return it in one of
1868 * the process_capture_result calls, and the call may be to just return the input
1869 * buffer, without metadata and output buffers; the sync fences must be handled
1870 * the same way they are done for output buffers.
1871 *
1872 *
1873 * Performance considerations:
1874 *
1875 * Applications will also receive these partial results immediately, so sending
1876 * partial results is a highly recommended performance optimization to avoid
1877 * the total pipeline latency before sending the results for what is known very
1878 * early on in the pipeline.
1879 *
1880 * A typical use case might be calculating the AF state halfway through the
1881 * pipeline; by sending the state back to the framework immediately, we get a
1882 * 50% performance increase and perceived responsiveness of the auto-focus.
1883 *
1884 */
1885typedef struct camera3_capture_result {
1886    /**
1887     * The frame number is an incrementing integer set by the framework in the
1888     * submitted request to uniquely identify this capture. It is also used to
1889     * identify the request in asynchronous notifications sent to
1890     * camera3_callback_ops_t.notify().
1891    */
1892    uint32_t frame_number;
1893
1894    /**
1895     * The result metadata for this capture. This contains information about the
1896     * final capture parameters, the state of the capture and post-processing
1897     * hardware, the state of the 3A algorithms, if enabled, and the output of
1898     * any enabled statistics units.
1899     *
1900     * Only one call to process_capture_result() with a given frame_number may
1901     * include the result metadata. All other calls for the same frame_number
1902     * must set this to NULL.
1903     *
1904     * If there was an error producing the result metadata, result must be an
1905     * empty metadata buffer, and notify() must be called with ERROR_RESULT.
1906     *
1907     * >= CAMERA_DEVICE_API_VERSION_3_2:
1908     *
1909     * Multiple calls to process_capture_result() with a given frame_number
1910     * may include the result metadata.
1911     *
1912     * Partial metadata submitted should not include any metadata key returned
1913     * in a previous partial result for a given frame. Each new partial result
1914     * for that frame must also set a distinct partial_result value.
1915     *
1916     * If notify has been called with ERROR_RESULT, all further partial
1917     * results for that frame are ignored by the framework.
1918     */
1919    const camera_metadata_t *result;
1920
1921    /**
1922     * The number of output buffers returned in this result structure. Must be
1923     * less than or equal to the matching capture request's count. If this is
1924     * less than the buffer count in the capture request, at least one more call
1925     * to process_capture_result with the same frame_number must be made, to
1926     * return the remaining output buffers to the framework. This may only be
1927     * zero if the structure includes valid result metadata or an input buffer
1928     * is returned in this result.
1929     */
1930    uint32_t num_output_buffers;
1931
1932    /**
1933     * The handles for the output stream buffers for this capture. They may not
1934     * yet be filled at the time the HAL calls process_capture_result(); the
1935     * framework will wait on the release sync fences provided by the HAL before
1936     * reading the buffers.
1937     *
1938     * The HAL must set the stream buffer's release sync fence to a valid sync
1939     * fd, or to -1 if the buffer has already been filled.
1940     *
1941     * If the HAL encounters an error while processing the buffer, and the
1942     * buffer is not filled, the buffer's status field must be set to
1943     * CAMERA3_BUFFER_STATUS_ERROR. If the HAL did not wait on the acquire fence
1944     * before encountering the error, the acquire fence should be copied into
1945     * the release fence, to allow the framework to wait on the fence before
1946     * reusing the buffer.
1947     *
1948     * The acquire fence must be set to -1 for all output buffers.  If
1949     * num_output_buffers is zero, this may be NULL. In that case, at least one
1950     * more process_capture_result call must be made by the HAL to provide the
1951     * output buffers.
1952     *
1953     * When process_capture_result is called with a new buffer for a frame,
1954     * all previous frames' buffers for that corresponding stream must have been
1955     * already delivered (the fences need not have yet been signaled).
1956     *
1957     * >= CAMERA_DEVICE_API_VERSION_3_2:
1958     *
1959     * Gralloc buffers for a frame may be sent to framework before the
1960     * corresponding SHUTTER-notify.
1961     *
1962     * Performance considerations:
1963     *
1964     * Buffers delivered to the framework will not be dispatched to the
1965     * application layer until a start of exposure timestamp has been received
1966     * via a SHUTTER notify() call. It is highly recommended to
1967     * dispatch that call as early as possible.
1968     */
1969     const camera3_stream_buffer_t *output_buffers;
1970
1971     /**
1972      * >= CAMERA_DEVICE_API_VERSION_3_2:
1973      *
1974      * The handle for the input stream buffer for this capture. It may not
1975      * yet be consumed at the time the HAL calls process_capture_result(); the
1976      * framework will wait on the release sync fences provided by the HAL before
1977      * reusing the buffer.
1978      *
1979      * The HAL should handle the sync fences the same way they are done for
1980      * output_buffers.
1981      *
1982      * Only one input buffer is allowed to be sent per request. Similarly to
1983      * output buffers, the ordering of returned input buffers must be
1984      * maintained by the HAL.
1985      *
1986      * Performance considerations:
1987      *
1988      * The input buffer should be returned as early as possible. If the HAL
1989      * supports sync fences, it can call process_capture_result to hand it back
1990      * with sync fences being set appropriately. If the sync fences are not
1991      * supported, the buffer can only be returned when it is consumed, which
1992      * may take long time; the HAL may choose to copy this input buffer to make
1993      * the buffer return sooner.
1994      */
1995      const camera3_stream_buffer_t *input_buffer;
1996
1997     /**
1998      * >= CAMERA_DEVICE_API_VERSION_3_2:
1999      *
2000      * In order to take advantage of partial results, the HAL must set the
2001      * static metadata android.request.partialResultCount to the number of
2002      * partial results it will send for each frame.
2003      *
2004      * Each new capture result with a partial result must set
2005      * this field (partial_result) to a distinct inclusive value between
2006      * 1 and android.request.partialResultCount.
2007      *
2008      * HALs not wishing to take advantage of this feature must not
2009      * set an android.request.partialResultCount or partial_result to a value
2010      * other than 1.
2011      *
2012      * This value must be set to 0 when a capture result contains buffers only
2013      * and no metadata.
2014      */
2015     uint32_t partial_result;
2016
2017} camera3_capture_result_t;
2018
2019/**********************************************************************
2020 *
2021 * Callback methods for the HAL to call into the framework.
2022 *
2023 * These methods are used to return metadata and image buffers for a completed
2024 * or failed captures, and to notify the framework of asynchronous events such
2025 * as errors.
2026 *
2027 * The framework will not call back into the HAL from within these callbacks,
2028 * and these calls will not block for extended periods.
2029 *
2030 */
2031typedef struct camera3_callback_ops {
2032
2033    /**
2034     * process_capture_result:
2035     *
2036     * Send results from a completed capture to the framework.
2037     * process_capture_result() may be invoked multiple times by the HAL in
2038     * response to a single capture request. This allows, for example, the
2039     * metadata and low-resolution buffers to be returned in one call, and
2040     * post-processed JPEG buffers in a later call, once it is available. Each
2041     * call must include the frame number of the request it is returning
2042     * metadata or buffers for.
2043     *
2044     * A component (buffer or metadata) of the complete result may only be
2045     * included in one process_capture_result call. A buffer for each stream,
2046     * and the result metadata, must be returned by the HAL for each request in
2047     * one of the process_capture_result calls, even in case of errors producing
2048     * some of the output. A call to process_capture_result() with neither
2049     * output buffers or result metadata is not allowed.
2050     *
2051     * The order of returning metadata and buffers for a single result does not
2052     * matter, but buffers for a given stream must be returned in FIFO order. So
2053     * the buffer for request 5 for stream A must always be returned before the
2054     * buffer for request 6 for stream A. This also applies to the result
2055     * metadata; the metadata for request 5 must be returned before the metadata
2056     * for request 6.
2057     *
2058     * However, different streams are independent of each other, so it is
2059     * acceptable and expected that the buffer for request 5 for stream A may be
2060     * returned after the buffer for request 6 for stream B is. And it is
2061     * acceptable that the result metadata for request 6 for stream B is
2062     * returned before the buffer for request 5 for stream A is.
2063     *
2064     * The HAL retains ownership of result structure, which only needs to be
2065     * valid to access during this call. The framework will copy whatever it
2066     * needs before this call returns.
2067     *
2068     * The output buffers do not need to be filled yet; the framework will wait
2069     * on the stream buffer release sync fence before reading the buffer
2070     * data. Therefore, this method should be called by the HAL as soon as
2071     * possible, even if some or all of the output buffers are still in
2072     * being filled. The HAL must include valid release sync fences into each
2073     * output_buffers stream buffer entry, or -1 if that stream buffer is
2074     * already filled.
2075     *
2076     * If the result buffer cannot be constructed for a request, the HAL should
2077     * return an empty metadata buffer, but still provide the output buffers and
2078     * their sync fences. In addition, notify() must be called with an
2079     * ERROR_RESULT message.
2080     *
2081     * If an output buffer cannot be filled, its status field must be set to
2082     * STATUS_ERROR. In addition, notify() must be called with a ERROR_BUFFER
2083     * message.
2084     *
2085     * If the entire capture has failed, then this method still needs to be
2086     * called to return the output buffers to the framework. All the buffer
2087     * statuses should be STATUS_ERROR, and the result metadata should be an
2088     * empty buffer. In addition, notify() must be called with a ERROR_REQUEST
2089     * message. In this case, individual ERROR_RESULT/ERROR_BUFFER messages
2090     * should not be sent.
2091     *
2092     * Performance requirements:
2093     *
2094     * This is a non-blocking call. The framework will return this call in 5ms.
2095     *
2096     * The pipeline latency (see S7 for definition) should be less than or equal to
2097     * 4 frame intervals, and must be less than or equal to 8 frame intervals.
2098     *
2099     */
2100    void (*process_capture_result)(const struct camera3_callback_ops *,
2101            const camera3_capture_result_t *result);
2102
2103    /**
2104     * notify:
2105     *
2106     * Asynchronous notification callback from the HAL, fired for various
2107     * reasons. Only for information independent of frame capture, or that
2108     * require specific timing. The ownership of the message structure remains
2109     * with the HAL, and the msg only needs to be valid for the duration of this
2110     * call.
2111     *
2112     * Multiple threads may call notify() simultaneously.
2113     *
2114     * <= CAMERA_DEVICE_API_VERSION_3_1:
2115     *
2116     * The notification for the start of exposure for a given request must be
2117     * sent by the HAL before the first call to process_capture_result() for
2118     * that request is made.
2119     *
2120     * >= CAMERA_DEVICE_API_VERSION_3_2:
2121     *
2122     * Buffers delivered to the framework will not be dispatched to the
2123     * application layer until a start of exposure timestamp has been received
2124     * via a SHUTTER notify() call. It is highly recommended to
2125     * dispatch this call as early as possible.
2126     *
2127     * ------------------------------------------------------------------------
2128     * Performance requirements:
2129     *
2130     * This is a non-blocking call. The framework will return this call in 5ms.
2131     */
2132    void (*notify)(const struct camera3_callback_ops *,
2133            const camera3_notify_msg_t *msg);
2134
2135} camera3_callback_ops_t;
2136
2137/**********************************************************************
2138 *
2139 * Camera device operations
2140 *
2141 */
2142typedef struct camera3_device_ops {
2143
2144    /**
2145     * initialize:
2146     *
2147     * One-time initialization to pass framework callback function pointers to
2148     * the HAL. Will be called once after a successful open() call, before any
2149     * other functions are called on the camera3_device_ops structure.
2150     *
2151     * Performance requirements:
2152     *
2153     * This should be a non-blocking call. The HAL should return from this call
2154     * in 5ms, and must return from this call in 10ms.
2155     *
2156     * Return values:
2157     *
2158     *  0:     On successful initialization
2159     *
2160     * -ENODEV: If initialization fails. Only close() can be called successfully
2161     *          by the framework after this.
2162     */
2163    int (*initialize)(const struct camera3_device *,
2164            const camera3_callback_ops_t *callback_ops);
2165
2166    /**********************************************************************
2167     * Stream management
2168     */
2169
2170    /**
2171     * configure_streams:
2172     *
2173     * CAMERA_DEVICE_API_VERSION_3_0 only:
2174     *
2175     * Reset the HAL camera device processing pipeline and set up new input and
2176     * output streams. This call replaces any existing stream configuration with
2177     * the streams defined in the stream_list. This method will be called at
2178     * least once after initialize() before a request is submitted with
2179     * process_capture_request().
2180     *
2181     * The stream_list must contain at least one output-capable stream, and may
2182     * not contain more than one input-capable stream.
2183     *
2184     * The stream_list may contain streams that are also in the currently-active
2185     * set of streams (from the previous call to configure_stream()). These
2186     * streams will already have valid values for usage, max_buffers, and the
2187     * private pointer.
2188     *
2189     * If such a stream has already had its buffers registered,
2190     * register_stream_buffers() will not be called again for the stream, and
2191     * buffers from the stream can be immediately included in input requests.
2192     *
2193     * If the HAL needs to change the stream configuration for an existing
2194     * stream due to the new configuration, it may rewrite the values of usage
2195     * and/or max_buffers during the configure call.
2196     *
2197     * The framework will detect such a change, and will then reallocate the
2198     * stream buffers, and call register_stream_buffers() again before using
2199     * buffers from that stream in a request.
2200     *
2201     * If a currently-active stream is not included in stream_list, the HAL may
2202     * safely remove any references to that stream. It will not be reused in a
2203     * later configure() call by the framework, and all the gralloc buffers for
2204     * it will be freed after the configure_streams() call returns.
2205     *
2206     * The stream_list structure is owned by the framework, and may not be
2207     * accessed once this call completes. The address of an individual
2208     * camera3_stream_t structure will remain valid for access by the HAL until
2209     * the end of the first configure_stream() call which no longer includes
2210     * that camera3_stream_t in the stream_list argument. The HAL may not change
2211     * values in the stream structure outside of the private pointer, except for
2212     * the usage and max_buffers members during the configure_streams() call
2213     * itself.
2214     *
2215     * If the stream is new, the usage, max_buffer, and private pointer fields
2216     * of the stream structure will all be set to 0. The HAL device must set
2217     * these fields before the configure_streams() call returns. These fields
2218     * are then used by the framework and the platform gralloc module to
2219     * allocate the gralloc buffers for each stream.
2220     *
2221     * Before such a new stream can have its buffers included in a capture
2222     * request, the framework will call register_stream_buffers() with that
2223     * stream. However, the framework is not required to register buffers for
2224     * _all_ streams before submitting a request. This allows for quick startup
2225     * of (for example) a preview stream, with allocation for other streams
2226     * happening later or concurrently.
2227     *
2228     * ------------------------------------------------------------------------
2229     * CAMERA_DEVICE_API_VERSION_3_1 only:
2230     *
2231     * Reset the HAL camera device processing pipeline and set up new input and
2232     * output streams. This call replaces any existing stream configuration with
2233     * the streams defined in the stream_list. This method will be called at
2234     * least once after initialize() before a request is submitted with
2235     * process_capture_request().
2236     *
2237     * The stream_list must contain at least one output-capable stream, and may
2238     * not contain more than one input-capable stream.
2239     *
2240     * The stream_list may contain streams that are also in the currently-active
2241     * set of streams (from the previous call to configure_stream()). These
2242     * streams will already have valid values for usage, max_buffers, and the
2243     * private pointer.
2244     *
2245     * If such a stream has already had its buffers registered,
2246     * register_stream_buffers() will not be called again for the stream, and
2247     * buffers from the stream can be immediately included in input requests.
2248     *
2249     * If the HAL needs to change the stream configuration for an existing
2250     * stream due to the new configuration, it may rewrite the values of usage
2251     * and/or max_buffers during the configure call.
2252     *
2253     * The framework will detect such a change, and will then reallocate the
2254     * stream buffers, and call register_stream_buffers() again before using
2255     * buffers from that stream in a request.
2256     *
2257     * If a currently-active stream is not included in stream_list, the HAL may
2258     * safely remove any references to that stream. It will not be reused in a
2259     * later configure() call by the framework, and all the gralloc buffers for
2260     * it will be freed after the configure_streams() call returns.
2261     *
2262     * The stream_list structure is owned by the framework, and may not be
2263     * accessed once this call completes. The address of an individual
2264     * camera3_stream_t structure will remain valid for access by the HAL until
2265     * the end of the first configure_stream() call which no longer includes
2266     * that camera3_stream_t in the stream_list argument. The HAL may not change
2267     * values in the stream structure outside of the private pointer, except for
2268     * the usage and max_buffers members during the configure_streams() call
2269     * itself.
2270     *
2271     * If the stream is new, max_buffer, and private pointer fields of the
2272     * stream structure will all be set to 0. The usage will be set to the
2273     * consumer usage flags. The HAL device must set these fields before the
2274     * configure_streams() call returns. These fields are then used by the
2275     * framework and the platform gralloc module to allocate the gralloc
2276     * buffers for each stream.
2277     *
2278     * Before such a new stream can have its buffers included in a capture
2279     * request, the framework will call register_stream_buffers() with that
2280     * stream. However, the framework is not required to register buffers for
2281     * _all_ streams before submitting a request. This allows for quick startup
2282     * of (for example) a preview stream, with allocation for other streams
2283     * happening later or concurrently.
2284     *
2285     * ------------------------------------------------------------------------
2286     * >= CAMERA_DEVICE_API_VERSION_3_2:
2287     *
2288     * Reset the HAL camera device processing pipeline and set up new input and
2289     * output streams. This call replaces any existing stream configuration with
2290     * the streams defined in the stream_list. This method will be called at
2291     * least once after initialize() before a request is submitted with
2292     * process_capture_request().
2293     *
2294     * The stream_list must contain at least one output-capable stream, and may
2295     * not contain more than one input-capable stream.
2296     *
2297     * The stream_list may contain streams that are also in the currently-active
2298     * set of streams (from the previous call to configure_stream()). These
2299     * streams will already have valid values for usage, max_buffers, and the
2300     * private pointer.
2301     *
2302     * If the HAL needs to change the stream configuration for an existing
2303     * stream due to the new configuration, it may rewrite the values of usage
2304     * and/or max_buffers during the configure call.
2305     *
2306     * The framework will detect such a change, and may then reallocate the
2307     * stream buffers before using buffers from that stream in a request.
2308     *
2309     * If a currently-active stream is not included in stream_list, the HAL may
2310     * safely remove any references to that stream. It will not be reused in a
2311     * later configure() call by the framework, and all the gralloc buffers for
2312     * it will be freed after the configure_streams() call returns.
2313     *
2314     * The stream_list structure is owned by the framework, and may not be
2315     * accessed once this call completes. The address of an individual
2316     * camera3_stream_t structure will remain valid for access by the HAL until
2317     * the end of the first configure_stream() call which no longer includes
2318     * that camera3_stream_t in the stream_list argument. The HAL may not change
2319     * values in the stream structure outside of the private pointer, except for
2320     * the usage and max_buffers members during the configure_streams() call
2321     * itself.
2322     *
2323     * If the stream is new, max_buffer, and private pointer fields of the
2324     * stream structure will all be set to 0. The usage will be set to the
2325     * consumer usage flags. The HAL device must set these fields before the
2326     * configure_streams() call returns. These fields are then used by the
2327     * framework and the platform gralloc module to allocate the gralloc
2328     * buffers for each stream.
2329     *
2330     * Newly allocated buffers may be included in a capture request at any time
2331     * by the framework. Once a gralloc buffer is returned to the framework
2332     * with process_capture_result (and its respective release_fence has been
2333     * signaled) the framework may free or reuse it at any time.
2334     *
2335     * ------------------------------------------------------------------------
2336     *
2337     * Preconditions:
2338     *
2339     * The framework will only call this method when no captures are being
2340     * processed. That is, all results have been returned to the framework, and
2341     * all in-flight input and output buffers have been returned and their
2342     * release sync fences have been signaled by the HAL. The framework will not
2343     * submit new requests for capture while the configure_streams() call is
2344     * underway.
2345     *
2346     * Postconditions:
2347     *
2348     * The HAL device must configure itself to provide maximum possible output
2349     * frame rate given the sizes and formats of the output streams, as
2350     * documented in the camera device's static metadata.
2351     *
2352     * Performance requirements:
2353     *
2354     * This call is expected to be heavyweight and possibly take several hundred
2355     * milliseconds to complete, since it may require resetting and
2356     * reconfiguring the image sensor and the camera processing pipeline.
2357     * Nevertheless, the HAL device should attempt to minimize the
2358     * reconfiguration delay to minimize the user-visible pauses during
2359     * application operational mode changes (such as switching from still
2360     * capture to video recording).
2361     *
2362     * The HAL should return from this call in 500ms, and must return from this
2363     * call in 1000ms.
2364     *
2365     * Return values:
2366     *
2367     *  0:      On successful stream configuration
2368     *
2369     * -EINVAL: If the requested stream configuration is invalid. Some examples
2370     *          of invalid stream configurations include:
2371     *
2372     *          - Including more than 1 input-capable stream (INPUT or
2373     *            BIDIRECTIONAL)
2374     *
2375     *          - Not including any output-capable streams (OUTPUT or
2376     *            BIDIRECTIONAL)
2377     *
2378     *          - Including streams with unsupported formats, or an unsupported
2379     *            size for that format.
2380     *
2381     *          - Including too many output streams of a certain format.
2382     *
2383     *          Note that the framework submitting an invalid stream
2384     *          configuration is not normal operation, since stream
2385     *          configurations are checked before configure. An invalid
2386     *          configuration means that a bug exists in the framework code, or
2387     *          there is a mismatch between the HAL's static metadata and the
2388     *          requirements on streams.
2389     *
2390     * -ENODEV: If there has been a fatal error and the device is no longer
2391     *          operational. Only close() can be called successfully by the
2392     *          framework after this error is returned.
2393     */
2394    int (*configure_streams)(const struct camera3_device *,
2395            camera3_stream_configuration_t *stream_list);
2396
2397    /**
2398     * register_stream_buffers:
2399     *
2400     * >= CAMERA_DEVICE_API_VERSION_3_2:
2401     *
2402     * DEPRECATED. This will not be called and must be set to NULL.
2403     *
2404     * <= CAMERA_DEVICE_API_VERSION_3_1:
2405     *
2406     * Register buffers for a given stream with the HAL device. This method is
2407     * called by the framework after a new stream is defined by
2408     * configure_streams, and before buffers from that stream are included in a
2409     * capture request. If the same stream is listed in a subsequent
2410     * configure_streams() call, register_stream_buffers will _not_ be called
2411     * again for that stream.
2412     *
2413     * The framework does not need to register buffers for all configured
2414     * streams before it submits the first capture request. This allows quick
2415     * startup for preview (or similar use cases) while other streams are still
2416     * being allocated.
2417     *
2418     * This method is intended to allow the HAL device to map or otherwise
2419     * prepare the buffers for later use. The buffers passed in will already be
2420     * locked for use. At the end of the call, all the buffers must be ready to
2421     * be returned to the stream.  The buffer_set argument is only valid for the
2422     * duration of this call.
2423     *
2424     * If the stream format was set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,
2425     * the camera HAL should inspect the passed-in buffers here to determine any
2426     * platform-private pixel format information.
2427     *
2428     * Performance requirements:
2429     *
2430     * This should be a non-blocking call. The HAL should return from this call
2431     * in 1ms, and must return from this call in 5ms.
2432     *
2433     * Return values:
2434     *
2435     *  0:      On successful registration of the new stream buffers
2436     *
2437     * -EINVAL: If the stream_buffer_set does not refer to a valid active
2438     *          stream, or if the buffers array is invalid.
2439     *
2440     * -ENOMEM: If there was a failure in registering the buffers. The framework
2441     *          must consider all the stream buffers to be unregistered, and can
2442     *          try to register again later.
2443     *
2444     * -ENODEV: If there is a fatal error, and the device is no longer
2445     *          operational. Only close() can be called successfully by the
2446     *          framework after this error is returned.
2447     */
2448    int (*register_stream_buffers)(const struct camera3_device *,
2449            const camera3_stream_buffer_set_t *buffer_set);
2450
2451    /**********************************************************************
2452     * Request creation and submission
2453     */
2454
2455    /**
2456     * construct_default_request_settings:
2457     *
2458     * Create capture settings for standard camera use cases.
2459     *
2460     * The device must return a settings buffer that is configured to meet the
2461     * requested use case, which must be one of the CAMERA3_TEMPLATE_*
2462     * enums. All request control fields must be included.
2463     *
2464     * The HAL retains ownership of this structure, but the pointer to the
2465     * structure must be valid until the device is closed. The framework and the
2466     * HAL may not modify the buffer once it is returned by this call. The same
2467     * buffer may be returned for subsequent calls for the same template, or for
2468     * other templates.
2469     *
2470     * Performance requirements:
2471     *
2472     * This should be a non-blocking call. The HAL should return from this call
2473     * in 1ms, and must return from this call in 5ms.
2474     *
2475     * Return values:
2476     *
2477     *   Valid metadata: On successful creation of a default settings
2478     *                   buffer.
2479     *
2480     *   NULL:           In case of a fatal error. After this is returned, only
2481     *                   the close() method can be called successfully by the
2482     *                   framework.
2483     */
2484    const camera_metadata_t* (*construct_default_request_settings)(
2485            const struct camera3_device *,
2486            int type);
2487
2488    /**
2489     * process_capture_request:
2490     *
2491     * Send a new capture request to the HAL. The HAL should not return from
2492     * this call until it is ready to accept the next request to process. Only
2493     * one call to process_capture_request() will be made at a time by the
2494     * framework, and the calls will all be from the same thread. The next call
2495     * to process_capture_request() will be made as soon as a new request and
2496     * its associated buffers are available. In a normal preview scenario, this
2497     * means the function will be called again by the framework almost
2498     * instantly.
2499     *
2500     * The actual request processing is asynchronous, with the results of
2501     * capture being returned by the HAL through the process_capture_result()
2502     * call. This call requires the result metadata to be available, but output
2503     * buffers may simply provide sync fences to wait on. Multiple requests are
2504     * expected to be in flight at once, to maintain full output frame rate.
2505     *
2506     * The framework retains ownership of the request structure. It is only
2507     * guaranteed to be valid during this call. The HAL device must make copies
2508     * of the information it needs to retain for the capture processing. The HAL
2509     * is responsible for waiting on and closing the buffers' fences and
2510     * returning the buffer handles to the framework.
2511     *
2512     * The HAL must write the file descriptor for the input buffer's release
2513     * sync fence into input_buffer->release_fence, if input_buffer is not
2514     * NULL. If the HAL returns -1 for the input buffer release sync fence, the
2515     * framework is free to immediately reuse the input buffer. Otherwise, the
2516     * framework will wait on the sync fence before refilling and reusing the
2517     * input buffer.
2518     *
2519     * >= CAMERA_DEVICE_API_VERSION_3_2:
2520     *
2521     * The input/output buffers provided by the framework in each request
2522     * may be brand new (having never before seen by the HAL).
2523     *
2524     * ------------------------------------------------------------------------
2525     * Performance considerations:
2526     *
2527     * Handling a new buffer should be extremely lightweight and there should be
2528     * no frame rate degradation or frame jitter introduced.
2529     *
2530     * This call must return fast enough to ensure that the requested frame
2531     * rate can be sustained, especially for streaming cases (post-processing
2532     * quality settings set to FAST). The HAL should return this call in 1
2533     * frame interval, and must return from this call in 4 frame intervals.
2534     *
2535     * Return values:
2536     *
2537     *  0:      On a successful start to processing the capture request
2538     *
2539     * -EINVAL: If the input is malformed (the settings are NULL when not
2540     *          allowed, there are 0 output buffers, etc) and capture processing
2541     *          cannot start. Failures during request processing should be
2542     *          handled by calling camera3_callback_ops_t.notify(). In case of
2543     *          this error, the framework will retain responsibility for the
2544     *          stream buffers' fences and the buffer handles; the HAL should
2545     *          not close the fences or return these buffers with
2546     *          process_capture_result.
2547     *
2548     * -ENODEV: If the camera device has encountered a serious error. After this
2549     *          error is returned, only the close() method can be successfully
2550     *          called by the framework.
2551     *
2552     */
2553    int (*process_capture_request)(const struct camera3_device *,
2554            camera3_capture_request_t *request);
2555
2556    /**********************************************************************
2557     * Miscellaneous methods
2558     */
2559
2560    /**
2561     * get_metadata_vendor_tag_ops:
2562     *
2563     * Get methods to query for vendor extension metadata tag information. The
2564     * HAL should fill in all the vendor tag operation methods, or leave ops
2565     * unchanged if no vendor tags are defined.
2566     *
2567     * The definition of vendor_tag_query_ops_t can be found in
2568     * system/media/camera/include/system/camera_metadata.h.
2569     *
2570     * >= CAMERA_DEVICE_API_VERSION_3_2:
2571     *    DEPRECATED. This function has been deprecated and should be set to
2572     *    NULL by the HAL.  Please implement get_vendor_tag_ops in camera_common.h
2573     *    instead.
2574     */
2575    void (*get_metadata_vendor_tag_ops)(const struct camera3_device*,
2576            vendor_tag_query_ops_t* ops);
2577
2578    /**
2579     * dump:
2580     *
2581     * Print out debugging state for the camera device. This will be called by
2582     * the framework when the camera service is asked for a debug dump, which
2583     * happens when using the dumpsys tool, or when capturing a bugreport.
2584     *
2585     * The passed-in file descriptor can be used to write debugging text using
2586     * dprintf() or write(). The text should be in ASCII encoding only.
2587     *
2588     * Performance requirements:
2589     *
2590     * This must be a non-blocking call. The HAL should return from this call
2591     * in 1ms, must return from this call in 10ms. This call must avoid
2592     * deadlocks, as it may be called at any point during camera operation.
2593     * Any synchronization primitives used (such as mutex locks or semaphores)
2594     * should be acquired with a timeout.
2595     */
2596    void (*dump)(const struct camera3_device *, int fd);
2597
2598    /**
2599     * flush:
2600     *
2601     * Flush all currently in-process captures and all buffers in the pipeline
2602     * on the given device. The framework will use this to dump all state as
2603     * quickly as possible in order to prepare for a configure_streams() call.
2604     *
2605     * No buffers are required to be successfully returned, so every buffer
2606     * held at the time of flush() (whether successfully filled or not) may be
2607     * returned with CAMERA3_BUFFER_STATUS_ERROR. Note the HAL is still allowed
2608     * to return valid (CAMERA3_BUFFER_STATUS_OK) buffers during this call,
2609     * provided they are successfully filled.
2610     *
2611     * All requests currently in the HAL are expected to be returned as soon as
2612     * possible.  Not-in-process requests should return errors immediately. Any
2613     * interruptible hardware blocks should be stopped, and any uninterruptible
2614     * blocks should be waited on.
2615     *
2616     * More specifically, the HAL must follow below requirements for various cases:
2617     *
2618     * 1. For captures that are too late for the HAL to cancel/stop, and will be
2619     *    completed normally by the HAL; i.e. the HAL can send shutter/notify and
2620     *    process_capture_result and buffers as normal.
2621     *
2622     * 2. For pending requests that have not done any processing, the HAL must call notify
2623     *    CAMERA3_MSG_ERROR_REQUEST, and return all the output buffers with
2624     *    process_capture_result in the error state (CAMERA3_BUFFER_STATUS_ERROR).
2625     *    The HAL must not place the release fence into an error state, instead,
2626     *    the release fences must be set to the acquire fences passed by the framework,
2627     *    or -1 if they have been waited on by the HAL already. This is also the path
2628     *    to follow for any captures for which the HAL already called notify() with
2629     *    CAMERA3_MSG_SHUTTER but won't be producing any metadata/valid buffers for.
2630     *    After CAMERA3_MSG_ERROR_REQUEST, for a given frame, only process_capture_results with
2631     *    buffers in CAMERA3_BUFFER_STATUS_ERROR are allowed. No further notifys or
2632     *    process_capture_result with non-null metadata is allowed.
2633     *
2634     * 3. For partially completed pending requests that will not have all the output
2635     *    buffers or perhaps missing metadata, the HAL should follow below:
2636     *
2637     *    3.1. Call notify with CAMERA3_MSG_ERROR_RESULT if some of the expected result
2638     *    metadata (i.e. one or more partial metadata) won't be available for the capture.
2639     *
2640     *    3.2. Call notify with CAMERA3_MSG_ERROR_BUFFER for every buffer that won't
2641     *         be produced for the capture.
2642     *
2643     *    3.3  Call notify with CAMERA3_MSG_SHUTTER with the capture timestamp before
2644     *         any buffers/metadata are returned with process_capture_result.
2645     *
2646     *    3.4 For captures that will produce some results, the HAL must not call
2647     *        CAMERA3_MSG_ERROR_REQUEST, since that indicates complete failure.
2648     *
2649     *    3.5. Valid buffers/metadata should be passed to the framework as normal.
2650     *
2651     *    3.6. Failed buffers should be returned to the framework as described for case 2.
2652     *         But failed buffers do not have to follow the strict ordering valid buffers do,
2653     *         and may be out-of-order with respect to valid buffers. For example, if buffers
2654     *         A, B, C, D, E are sent, D and E are failed, then A, E, B, D, C is an acceptable
2655     *         return order.
2656     *
2657     *    3.7. For fully-missing metadata, calling CAMERA3_MSG_ERROR_RESULT is sufficient, no
2658     *         need to call process_capture_result with NULL metadata or equivalent.
2659     *
2660     * flush() should only return when there are no more outstanding buffers or
2661     * requests left in the HAL. The framework may call configure_streams (as
2662     * the HAL state is now quiesced) or may issue new requests.
2663     *
2664     * Note that it's sufficient to only support fully-succeeded and fully-failed result cases.
2665     * However, it is highly desirable to support the partial failure cases as well, as it
2666     * could help improve the flush call overall performance.
2667     *
2668     * Performance requirements:
2669     *
2670     * The HAL should return from this call in 100ms, and must return from this
2671     * call in 1000ms. And this call must not be blocked longer than pipeline
2672     * latency (see S7 for definition).
2673     *
2674     * Version information:
2675     *
2676     *   only available if device version >= CAMERA_DEVICE_API_VERSION_3_1.
2677     *
2678     * Return values:
2679     *
2680     *  0:      On a successful flush of the camera HAL.
2681     *
2682     * -EINVAL: If the input is malformed (the device is not valid).
2683     *
2684     * -ENODEV: If the camera device has encountered a serious error. After this
2685     *          error is returned, only the close() method can be successfully
2686     *          called by the framework.
2687     */
2688    int (*flush)(const struct camera3_device *);
2689
2690    /* reserved for future use */
2691    void *reserved[8];
2692} camera3_device_ops_t;
2693
2694/**********************************************************************
2695 *
2696 * Camera device definition
2697 *
2698 */
2699typedef struct camera3_device {
2700    /**
2701     * common.version must equal CAMERA_DEVICE_API_VERSION_3_0 to identify this
2702     * device as implementing version 3.0 of the camera device HAL.
2703     *
2704     * Performance requirements:
2705     *
2706     * Camera open (common.module->common.methods->open) should return in 200ms, and must return
2707     * in 500ms.
2708     * Camera close (common.close) should return in 200ms, and must return in 500ms.
2709     *
2710     */
2711    hw_device_t common;
2712    camera3_device_ops_t *ops;
2713    void *priv;
2714} camera3_device_t;
2715
2716__END_DECLS
2717
2718#endif /* #ifdef ANDROID_INCLUDE_CAMERA3_H */
2719