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#define LOG_TAG "Camera2-ZslProcessor3"
18#define ATRACE_TAG ATRACE_TAG_CAMERA
19//#define LOG_NDEBUG 0
20//#define LOG_NNDEBUG 0
21
22#ifdef LOG_NNDEBUG
23#define ALOGVV(...) ALOGV(__VA_ARGS__)
24#else
25#define ALOGVV(...) ((void)0)
26#endif
27
28#include <inttypes.h>
29
30#include <utils/Log.h>
31#include <utils/Trace.h>
32#include <gui/Surface.h>
33
34#include "common/CameraDeviceBase.h"
35#include "api1/Camera2Client.h"
36#include "api1/client2/CaptureSequencer.h"
37#include "api1/client2/ZslProcessor3.h"
38#include "device3/Camera3Device.h"
39
40namespace android {
41namespace camera2 {
42
43ZslProcessor3::ZslProcessor3(
44    sp<Camera2Client> client,
45    wp<CaptureSequencer> sequencer):
46        Thread(false),
47        mLatestClearedBufferTimestamp(0),
48        mState(RUNNING),
49        mClient(client),
50        mSequencer(sequencer),
51        mId(client->getCameraId()),
52        mZslStreamId(NO_STREAM),
53        mFrameListHead(0),
54        mZslQueueHead(0),
55        mZslQueueTail(0),
56        mHasFocuser(false) {
57    // Initialize buffer queue and frame list based on pipeline max depth.
58    size_t pipelineMaxDepth = kDefaultMaxPipelineDepth;
59    if (client != 0) {
60        sp<Camera3Device> device =
61        static_cast<Camera3Device*>(client->getCameraDevice().get());
62        if (device != 0) {
63            camera_metadata_ro_entry_t entry =
64                device->info().find(ANDROID_REQUEST_PIPELINE_MAX_DEPTH);
65            if (entry.count == 1) {
66                pipelineMaxDepth = entry.data.u8[0];
67            } else {
68                ALOGW("%s: Unable to find the android.request.pipelineMaxDepth,"
69                        " use default pipeline max depth %zu", __FUNCTION__,
70                        kDefaultMaxPipelineDepth);
71            }
72
73            entry = device->info().find(ANDROID_LENS_INFO_MINIMUM_FOCUS_DISTANCE);
74            if (entry.count > 0 && entry.data.f[0] != 0.) {
75                mHasFocuser = true;
76            }
77        }
78    }
79
80    ALOGV("%s: Initialize buffer queue and frame list depth based on max pipeline depth (%d)",
81          __FUNCTION__, pipelineMaxDepth);
82    // Need to keep buffer queue longer than metadata queue because sometimes buffer arrives
83    // earlier than metadata which causes the buffer corresponding to oldest metadata being
84    // removed.
85    mFrameListDepth = pipelineMaxDepth;
86    mBufferQueueDepth = mFrameListDepth + 1;
87
88
89    mZslQueue.insertAt(0, mBufferQueueDepth);
90    mFrameList.insertAt(0, mFrameListDepth);
91    sp<CaptureSequencer> captureSequencer = mSequencer.promote();
92    if (captureSequencer != 0) captureSequencer->setZslProcessor(this);
93}
94
95ZslProcessor3::~ZslProcessor3() {
96    ALOGV("%s: Exit", __FUNCTION__);
97    deleteStream();
98}
99
100void ZslProcessor3::onResultAvailable(const CaptureResult &result) {
101    ATRACE_CALL();
102    ALOGV("%s:", __FUNCTION__);
103    Mutex::Autolock l(mInputMutex);
104    camera_metadata_ro_entry_t entry;
105    entry = result.mMetadata.find(ANDROID_SENSOR_TIMESTAMP);
106    nsecs_t timestamp = entry.data.i64[0];
107    if (entry.count == 0) {
108        ALOGE("%s: metadata doesn't have timestamp, skip this result", __FUNCTION__);
109        return;
110    }
111
112    entry = result.mMetadata.find(ANDROID_REQUEST_FRAME_COUNT);
113    if (entry.count == 0) {
114        ALOGE("%s: metadata doesn't have frame number, skip this result", __FUNCTION__);
115        return;
116    }
117    int32_t frameNumber = entry.data.i32[0];
118
119    ALOGVV("Got preview metadata for frame %d with timestamp %" PRId64, frameNumber, timestamp);
120
121    if (mState != RUNNING) return;
122
123    // Corresponding buffer has been cleared. No need to push into mFrameList
124    if (timestamp <= mLatestClearedBufferTimestamp) return;
125
126    mFrameList.editItemAt(mFrameListHead) = result.mMetadata;
127    mFrameListHead = (mFrameListHead + 1) % mFrameListDepth;
128}
129
130status_t ZslProcessor3::updateStream(const Parameters &params) {
131    ATRACE_CALL();
132    ALOGV("%s: Configuring ZSL streams", __FUNCTION__);
133    status_t res;
134
135    Mutex::Autolock l(mInputMutex);
136
137    sp<Camera2Client> client = mClient.promote();
138    if (client == 0) {
139        ALOGE("%s: Camera %d: Client does not exist", __FUNCTION__, mId);
140        return INVALID_OPERATION;
141    }
142    sp<Camera3Device> device =
143        static_cast<Camera3Device*>(client->getCameraDevice().get());
144    if (device == 0) {
145        ALOGE("%s: Camera %d: Device does not exist", __FUNCTION__, mId);
146        return INVALID_OPERATION;
147    }
148
149    if (mZslStreamId != NO_STREAM) {
150        // Check if stream parameters have to change
151        uint32_t currentWidth, currentHeight;
152        res = device->getStreamInfo(mZslStreamId,
153                &currentWidth, &currentHeight, 0);
154        if (res != OK) {
155            ALOGE("%s: Camera %d: Error querying capture output stream info: "
156                    "%s (%d)", __FUNCTION__,
157                    client->getCameraId(), strerror(-res), res);
158            return res;
159        }
160        if (currentWidth != (uint32_t)params.fastInfo.arrayWidth ||
161                currentHeight != (uint32_t)params.fastInfo.arrayHeight) {
162            ALOGV("%s: Camera %d: Deleting stream %d since the buffer "
163                  "dimensions changed",
164                __FUNCTION__, client->getCameraId(), mZslStreamId);
165            res = device->deleteStream(mZslStreamId);
166            if (res == -EBUSY) {
167                ALOGV("%s: Camera %d: Device is busy, call updateStream again "
168                      " after it becomes idle", __FUNCTION__, mId);
169                return res;
170            } else if(res != OK) {
171                ALOGE("%s: Camera %d: Unable to delete old output stream "
172                        "for ZSL: %s (%d)", __FUNCTION__,
173                        client->getCameraId(), strerror(-res), res);
174                return res;
175            }
176            mZslStreamId = NO_STREAM;
177        }
178    }
179
180    if (mZslStreamId == NO_STREAM) {
181        // Create stream for HAL production
182        // TODO: Sort out better way to select resolution for ZSL
183
184        // Note that format specified internally in Camera3ZslStream
185        res = device->createZslStream(
186                params.fastInfo.arrayWidth, params.fastInfo.arrayHeight,
187                mBufferQueueDepth,
188                &mZslStreamId,
189                &mZslStream);
190        if (res != OK) {
191            ALOGE("%s: Camera %d: Can't create ZSL stream: "
192                    "%s (%d)", __FUNCTION__, client->getCameraId(),
193                    strerror(-res), res);
194            return res;
195        }
196
197        // Only add the camera3 buffer listener when the stream is created.
198        mZslStream->addBufferListener(this);
199    }
200
201    client->registerFrameListener(Camera2Client::kPreviewRequestIdStart,
202            Camera2Client::kPreviewRequestIdEnd,
203            this,
204            /*sendPartials*/false);
205
206    return OK;
207}
208
209status_t ZslProcessor3::deleteStream() {
210    ATRACE_CALL();
211    status_t res;
212
213    Mutex::Autolock l(mInputMutex);
214
215    if (mZslStreamId != NO_STREAM) {
216        sp<Camera2Client> client = mClient.promote();
217        if (client == 0) {
218            ALOGE("%s: Camera %d: Client does not exist", __FUNCTION__, mId);
219            return INVALID_OPERATION;
220        }
221
222        sp<Camera3Device> device =
223            reinterpret_cast<Camera3Device*>(client->getCameraDevice().get());
224        if (device == 0) {
225            ALOGE("%s: Camera %d: Device does not exist", __FUNCTION__, mId);
226            return INVALID_OPERATION;
227        }
228
229        res = device->deleteStream(mZslStreamId);
230        if (res != OK) {
231            ALOGE("%s: Camera %d: Cannot delete ZSL output stream %d: "
232                    "%s (%d)", __FUNCTION__, client->getCameraId(),
233                    mZslStreamId, strerror(-res), res);
234            return res;
235        }
236
237        mZslStreamId = NO_STREAM;
238    }
239    return OK;
240}
241
242int ZslProcessor3::getStreamId() const {
243    Mutex::Autolock l(mInputMutex);
244    return mZslStreamId;
245}
246
247status_t ZslProcessor3::updateRequestWithDefaultStillRequest(CameraMetadata &request) const {
248    sp<Camera2Client> client = mClient.promote();
249    if (client == 0) {
250        ALOGE("%s: Camera %d: Client does not exist", __FUNCTION__, mId);
251        return INVALID_OPERATION;
252    }
253    sp<Camera3Device> device =
254        static_cast<Camera3Device*>(client->getCameraDevice().get());
255    if (device == 0) {
256        ALOGE("%s: Camera %d: Device does not exist", __FUNCTION__, mId);
257        return INVALID_OPERATION;
258    }
259
260    CameraMetadata stillTemplate;
261    device->createDefaultRequest(CAMERA3_TEMPLATE_STILL_CAPTURE, &stillTemplate);
262
263    // Find some of the post-processing tags, and assign the value from template to the request.
264    // Only check the aberration mode and noise reduction mode for now, as they are very important
265    // for image quality.
266    uint32_t postProcessingTags[] = {
267            ANDROID_NOISE_REDUCTION_MODE,
268            ANDROID_COLOR_CORRECTION_ABERRATION_MODE,
269            ANDROID_COLOR_CORRECTION_MODE,
270            ANDROID_TONEMAP_MODE,
271            ANDROID_SHADING_MODE,
272            ANDROID_HOT_PIXEL_MODE,
273            ANDROID_EDGE_MODE
274    };
275
276    camera_metadata_entry_t entry;
277    for (size_t i = 0; i < sizeof(postProcessingTags) / sizeof(uint32_t); i++) {
278        entry = stillTemplate.find(postProcessingTags[i]);
279        if (entry.count > 0) {
280            request.update(postProcessingTags[i], entry.data.u8, 1);
281        }
282    }
283
284    return OK;
285}
286
287status_t ZslProcessor3::pushToReprocess(int32_t requestId) {
288    ALOGV("%s: Send in reprocess request with id %d",
289            __FUNCTION__, requestId);
290    Mutex::Autolock l(mInputMutex);
291    status_t res;
292    sp<Camera2Client> client = mClient.promote();
293
294    if (client == 0) {
295        ALOGE("%s: Camera %d: Client does not exist", __FUNCTION__, mId);
296        return INVALID_OPERATION;
297    }
298
299    IF_ALOGV() {
300        dumpZslQueue(-1);
301    }
302
303    size_t metadataIdx;
304    nsecs_t candidateTimestamp = getCandidateTimestampLocked(&metadataIdx);
305
306    if (candidateTimestamp == -1) {
307        ALOGE("%s: Could not find good candidate for ZSL reprocessing",
308              __FUNCTION__);
309        return NOT_ENOUGH_DATA;
310    }
311
312    res = mZslStream->enqueueInputBufferByTimestamp(candidateTimestamp,
313                                                    /*actualTimestamp*/NULL);
314
315    if (res == mZslStream->NO_BUFFER_AVAILABLE) {
316        ALOGV("%s: No ZSL buffers yet", __FUNCTION__);
317        return NOT_ENOUGH_DATA;
318    } else if (res != OK) {
319        ALOGE("%s: Unable to push buffer for reprocessing: %s (%d)",
320                __FUNCTION__, strerror(-res), res);
321        return res;
322    }
323
324    {
325        CameraMetadata request = mFrameList[metadataIdx];
326
327        // Verify that the frame is reasonable for reprocessing
328
329        camera_metadata_entry_t entry;
330        entry = request.find(ANDROID_CONTROL_AE_STATE);
331        if (entry.count == 0) {
332            ALOGE("%s: ZSL queue frame has no AE state field!",
333                    __FUNCTION__);
334            return BAD_VALUE;
335        }
336        if (entry.data.u8[0] != ANDROID_CONTROL_AE_STATE_CONVERGED &&
337                entry.data.u8[0] != ANDROID_CONTROL_AE_STATE_LOCKED) {
338            ALOGV("%s: ZSL queue frame AE state is %d, need full capture",
339                    __FUNCTION__, entry.data.u8[0]);
340            return NOT_ENOUGH_DATA;
341        }
342
343        uint8_t requestType = ANDROID_REQUEST_TYPE_REPROCESS;
344        res = request.update(ANDROID_REQUEST_TYPE,
345                &requestType, 1);
346        if (res != OK) {
347            ALOGE("%s: Unable to update request type",
348                  __FUNCTION__);
349            return INVALID_OPERATION;
350        }
351
352        int32_t inputStreams[1] =
353                { mZslStreamId };
354        res = request.update(ANDROID_REQUEST_INPUT_STREAMS,
355                inputStreams, 1);
356        if (res != OK) {
357            ALOGE("%s: Unable to update request input streams",
358                  __FUNCTION__);
359            return INVALID_OPERATION;
360        }
361
362        uint8_t captureIntent =
363                static_cast<uint8_t>(ANDROID_CONTROL_CAPTURE_INTENT_STILL_CAPTURE);
364        res = request.update(ANDROID_CONTROL_CAPTURE_INTENT,
365                &captureIntent, 1);
366        if (res != OK ) {
367            ALOGE("%s: Unable to update request capture intent",
368                  __FUNCTION__);
369            return INVALID_OPERATION;
370        }
371
372        // TODO: Shouldn't we also update the latest preview frame?
373        int32_t outputStreams[1] =
374                { client->getCaptureStreamId() };
375        res = request.update(ANDROID_REQUEST_OUTPUT_STREAMS,
376                outputStreams, 1);
377        if (res != OK) {
378            ALOGE("%s: Unable to update request output streams",
379                  __FUNCTION__);
380            return INVALID_OPERATION;
381        }
382
383        res = request.update(ANDROID_REQUEST_ID,
384                &requestId, 1);
385        if (res != OK ) {
386            ALOGE("%s: Unable to update frame to a reprocess request",
387                  __FUNCTION__);
388            return INVALID_OPERATION;
389        }
390
391        res = client->stopStream();
392        if (res != OK) {
393            ALOGE("%s: Camera %d: Unable to stop preview for ZSL capture: "
394                "%s (%d)",
395                __FUNCTION__, client->getCameraId(), strerror(-res), res);
396            return INVALID_OPERATION;
397        }
398
399        // Update JPEG settings
400        {
401            SharedParameters::Lock l(client->getParameters());
402            res = l.mParameters.updateRequestJpeg(&request);
403            if (res != OK) {
404                ALOGE("%s: Camera %d: Unable to update JPEG entries of ZSL "
405                        "capture request: %s (%d)", __FUNCTION__,
406                        client->getCameraId(),
407                        strerror(-res), res);
408                return res;
409            }
410        }
411
412        // Update post-processing settings
413        res = updateRequestWithDefaultStillRequest(request);
414        if (res != OK) {
415            ALOGW("%s: Unable to update post-processing tags, the reprocessed image quality "
416                    "may be compromised", __FUNCTION__);
417        }
418
419        mLatestCapturedRequest = request;
420        res = client->getCameraDevice()->capture(request);
421        if (res != OK ) {
422            ALOGE("%s: Unable to send ZSL reprocess request to capture: %s"
423                  " (%d)", __FUNCTION__, strerror(-res), res);
424            return res;
425        }
426
427        mState = LOCKED;
428    }
429
430    return OK;
431}
432
433status_t ZslProcessor3::clearZslQueue() {
434    Mutex::Autolock l(mInputMutex);
435    // If in middle of capture, can't clear out queue
436    if (mState == LOCKED) return OK;
437
438    return clearZslQueueLocked();
439}
440
441status_t ZslProcessor3::clearZslQueueLocked() {
442    if (mZslStream != 0) {
443        // clear result metadata list first.
444        clearZslResultQueueLocked();
445        return mZslStream->clearInputRingBuffer(&mLatestClearedBufferTimestamp);
446    }
447    return OK;
448}
449
450void ZslProcessor3::clearZslResultQueueLocked() {
451    mFrameList.clear();
452    mFrameListHead = 0;
453    mFrameList.insertAt(0, mFrameListDepth);
454}
455
456void ZslProcessor3::dump(int fd, const Vector<String16>& /*args*/) const {
457    Mutex::Autolock l(mInputMutex);
458    if (!mLatestCapturedRequest.isEmpty()) {
459        String8 result("    Latest ZSL capture request:\n");
460        write(fd, result.string(), result.size());
461        mLatestCapturedRequest.dump(fd, 2, 6);
462    } else {
463        String8 result("    Latest ZSL capture request: none yet\n");
464        write(fd, result.string(), result.size());
465    }
466    dumpZslQueue(fd);
467}
468
469bool ZslProcessor3::threadLoop() {
470    // TODO: remove dependency on thread. For now, shut thread down right
471    // away.
472    return false;
473}
474
475void ZslProcessor3::dumpZslQueue(int fd) const {
476    String8 header("ZSL queue contents:");
477    String8 indent("    ");
478    ALOGV("%s", header.string());
479    if (fd != -1) {
480        header = indent + header + "\n";
481        write(fd, header.string(), header.size());
482    }
483    for (size_t i = 0; i < mZslQueue.size(); i++) {
484        const ZslPair &queueEntry = mZslQueue[i];
485        nsecs_t bufferTimestamp = queueEntry.buffer.mTimestamp;
486        camera_metadata_ro_entry_t entry;
487        nsecs_t frameTimestamp = 0;
488        int frameAeState = -1;
489        if (!queueEntry.frame.isEmpty()) {
490            entry = queueEntry.frame.find(ANDROID_SENSOR_TIMESTAMP);
491            if (entry.count > 0) frameTimestamp = entry.data.i64[0];
492            entry = queueEntry.frame.find(ANDROID_CONTROL_AE_STATE);
493            if (entry.count > 0) frameAeState = entry.data.u8[0];
494        }
495        String8 result =
496                String8::format("   %zu: b: %" PRId64 "\tf: %" PRId64 ", AE state: %d", i,
497                        bufferTimestamp, frameTimestamp, frameAeState);
498        ALOGV("%s", result.string());
499        if (fd != -1) {
500            result = indent + result + "\n";
501            write(fd, result.string(), result.size());
502        }
503
504    }
505}
506
507bool ZslProcessor3::isFixedFocusMode(uint8_t afMode) const {
508    switch (afMode) {
509        case ANDROID_CONTROL_AF_MODE_AUTO:
510        case ANDROID_CONTROL_AF_MODE_CONTINUOUS_VIDEO:
511        case ANDROID_CONTROL_AF_MODE_CONTINUOUS_PICTURE:
512        case ANDROID_CONTROL_AF_MODE_MACRO:
513            return false;
514            break;
515        case ANDROID_CONTROL_AF_MODE_OFF:
516        case ANDROID_CONTROL_AF_MODE_EDOF:
517            return true;
518        default:
519            ALOGE("%s: unknown focus mode %d", __FUNCTION__, afMode);
520            return false;
521    }
522}
523
524nsecs_t ZslProcessor3::getCandidateTimestampLocked(size_t* metadataIdx) const {
525    /**
526     * Find the smallest timestamp we know about so far
527     * - ensure that aeState is either converged or locked
528     */
529
530    size_t idx = 0;
531    nsecs_t minTimestamp = -1;
532
533    size_t emptyCount = mFrameList.size();
534
535    for (size_t j = 0; j < mFrameList.size(); j++) {
536        const CameraMetadata &frame = mFrameList[j];
537        if (!frame.isEmpty()) {
538
539            emptyCount--;
540
541            camera_metadata_ro_entry_t entry;
542            entry = frame.find(ANDROID_SENSOR_TIMESTAMP);
543            if (entry.count == 0) {
544                ALOGE("%s: Can't find timestamp in frame!",
545                        __FUNCTION__);
546                continue;
547            }
548            nsecs_t frameTimestamp = entry.data.i64[0];
549            if (minTimestamp > frameTimestamp || minTimestamp == -1) {
550
551                entry = frame.find(ANDROID_CONTROL_AE_STATE);
552
553                if (entry.count == 0) {
554                    /**
555                     * This is most likely a HAL bug. The aeState field is
556                     * mandatory, so it should always be in a metadata packet.
557                     */
558                    ALOGW("%s: ZSL queue frame has no AE state field!",
559                            __FUNCTION__);
560                    continue;
561                }
562                if (entry.data.u8[0] != ANDROID_CONTROL_AE_STATE_CONVERGED &&
563                        entry.data.u8[0] != ANDROID_CONTROL_AE_STATE_LOCKED) {
564                    ALOGVV("%s: ZSL queue frame AE state is %d, need "
565                           "full capture",  __FUNCTION__, entry.data.u8[0]);
566                    continue;
567                }
568
569                entry = frame.find(ANDROID_CONTROL_AF_MODE);
570                if (entry.count == 0) {
571                    ALOGW("%s: ZSL queue frame has no AF mode field!",
572                            __FUNCTION__);
573                    continue;
574                }
575                uint8_t afMode = entry.data.u8[0];
576                if (afMode == ANDROID_CONTROL_AF_MODE_OFF) {
577                    // Skip all the ZSL buffer for manual AF mode, as we don't really
578                    // know the af state.
579                    continue;
580                }
581
582                // Check AF state if device has focuser and focus mode isn't fixed
583                if (mHasFocuser && !isFixedFocusMode(afMode)) {
584                    // Make sure the candidate frame has good focus.
585                    entry = frame.find(ANDROID_CONTROL_AF_STATE);
586                    if (entry.count == 0) {
587                        ALOGW("%s: ZSL queue frame has no AF state field!",
588                                __FUNCTION__);
589                        continue;
590                    }
591                    uint8_t afState = entry.data.u8[0];
592                    if (afState != ANDROID_CONTROL_AF_STATE_PASSIVE_FOCUSED &&
593                            afState != ANDROID_CONTROL_AF_STATE_FOCUSED_LOCKED &&
594                            afState != ANDROID_CONTROL_AF_STATE_NOT_FOCUSED_LOCKED) {
595                        ALOGVV("%s: ZSL queue frame AF state is %d is not good for capture, skip it",
596                                __FUNCTION__, afState);
597                        continue;
598                    }
599                }
600
601                minTimestamp = frameTimestamp;
602                idx = j;
603            }
604
605            ALOGVV("%s: Saw timestamp %" PRId64, __FUNCTION__, frameTimestamp);
606        }
607    }
608
609    if (emptyCount == mFrameList.size()) {
610        /**
611         * This could be mildly bad and means our ZSL was triggered before
612         * there were any frames yet received by the camera framework.
613         *
614         * This is a fairly corner case which can happen under:
615         * + a user presses the shutter button real fast when the camera starts
616         *     (startPreview followed immediately by takePicture).
617         * + burst capture case (hitting shutter button as fast possible)
618         *
619         * If this happens in steady case (preview running for a while, call
620         *     a single takePicture) then this might be a fwk bug.
621         */
622        ALOGW("%s: ZSL queue has no metadata frames", __FUNCTION__);
623    }
624
625    ALOGV("%s: Candidate timestamp %" PRId64 " (idx %zu), empty frames: %zu",
626          __FUNCTION__, minTimestamp, idx, emptyCount);
627
628    if (metadataIdx) {
629        *metadataIdx = idx;
630    }
631
632    return minTimestamp;
633}
634
635void ZslProcessor3::onBufferAcquired(const BufferInfo& /*bufferInfo*/) {
636    // Intentionally left empty
637    // Although theoretically we could use this to get better dump info
638}
639
640void ZslProcessor3::onBufferReleased(const BufferInfo& bufferInfo) {
641
642    // ignore output buffers
643    if (bufferInfo.mOutput) {
644        return;
645    }
646
647    // Lock mutex only once we know this is an input buffer returned to avoid
648    // potential deadlock
649    Mutex::Autolock l(mInputMutex);
650    // TODO: Verify that the buffer is in our queue by looking at timestamp
651    // theoretically unnecessary unless we change the following assumptions:
652    // -- only 1 buffer reprocessed at a time (which is the case now)
653
654    // Erase entire ZSL queue since we've now completed the capture and preview
655    // is stopped.
656    //
657    // We need to guarantee that if we do two back-to-back captures,
658    // the second won't use a buffer that's older/the same as the first, which
659    // is theoretically possible if we don't clear out the queue and the
660    // selection criteria is something like 'newest'. Clearing out the result
661    // metadata queue on a completed capture ensures we'll only use new timestamp.
662    // Calling clearZslQueueLocked is a guaranteed deadlock because this callback
663    // holds the Camera3Stream internal lock (mLock), and clearZslQueueLocked requires
664    // to hold the same lock.
665    // TODO: need figure out a way to clear the Zsl buffer queue properly. Right now
666    // it is safe not to do so, as back to back ZSL capture requires stop and start
667    // preview, which will flush ZSL queue automatically.
668    ALOGV("%s: Memory optimization, clearing ZSL queue",
669          __FUNCTION__);
670    clearZslResultQueueLocked();
671
672    // Required so we accept more ZSL requests
673    mState = RUNNING;
674}
675
676}; // namespace camera2
677}; // namespace android
678