AudioTrack.h revision fb1fdc9d6603aa228362e7349451f6455c9849c2
1/*
2 * Copyright (C) 2007 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_AUDIOTRACK_H
18#define ANDROID_AUDIOTRACK_H
19
20#include <cutils/sched_policy.h>
21#include <media/AudioSystem.h>
22#include <media/IAudioTrack.h>
23#include <utils/threads.h>
24
25namespace android {
26
27// ----------------------------------------------------------------------------
28
29class audio_track_cblk_t;
30class AudioTrackClientProxy;
31class StaticAudioTrackClientProxy;
32
33// ----------------------------------------------------------------------------
34
35class AudioTrack : public RefBase
36{
37public:
38    enum channel_index {
39        MONO   = 0,
40        LEFT   = 0,
41        RIGHT  = 1
42    };
43
44    /* Events used by AudioTrack callback function (callback_t).
45     * Keep in sync with frameworks/base/media/java/android/media/AudioTrack.java NATIVE_EVENT_*.
46     */
47    enum event_type {
48        EVENT_MORE_DATA = 0,        // Request to write more data to buffer.
49                                    // If this event is delivered but the callback handler
50                                    // does not want to write more data, the handler must explicitly
51                                    // ignore the event by setting frameCount to zero.
52        EVENT_UNDERRUN = 1,         // Buffer underrun occurred.
53        EVENT_LOOP_END = 2,         // Sample loop end was reached; playback restarted from
54                                    // loop start if loop count was not 0.
55        EVENT_MARKER = 3,           // Playback head is at the specified marker position
56                                    // (See setMarkerPosition()).
57        EVENT_NEW_POS = 4,          // Playback head is at a new position
58                                    // (See setPositionUpdatePeriod()).
59        EVENT_BUFFER_END = 5,       // Playback head is at the end of the buffer.
60                                    // Not currently used by android.media.AudioTrack.
61        EVENT_NEW_IAUDIOTRACK = 6,  // IAudioTrack was re-created, either due to re-routing and
62                                    // voluntary invalidation by mediaserver, or mediaserver crash.
63        EVENT_STREAM_END = 7,       // Sent after all the buffers queued in AF and HW are played
64                                    // back (after stop is called)
65    };
66
67    /* Client should declare Buffer on the stack and pass address to obtainBuffer()
68     * and releaseBuffer().  See also callback_t for EVENT_MORE_DATA.
69     */
70
71    class Buffer
72    {
73    public:
74        // FIXME use m prefix
75        size_t      frameCount;   // number of sample frames corresponding to size;
76                                  // on input it is the number of frames desired,
77                                  // on output is the number of frames actually filled
78                                  // (currently ignored, but will make the primary field in future)
79
80        size_t      size;         // input/output in bytes == frameCount * frameSize
81                                  // on output is the number of bytes actually filled
82                                  // FIXME this is redundant with respect to frameCount,
83                                  // and TRANSFER_OBTAIN mode is broken for 8-bit data
84                                  // since we don't define the frame format
85
86        union {
87            void*       raw;
88            short*      i16;      // signed 16-bit
89            int8_t*     i8;       // unsigned 8-bit, offset by 0x80
90        };
91    };
92
93    /* As a convenience, if a callback is supplied, a handler thread
94     * is automatically created with the appropriate priority. This thread
95     * invokes the callback when a new buffer becomes available or various conditions occur.
96     * Parameters:
97     *
98     * event:   type of event notified (see enum AudioTrack::event_type).
99     * user:    Pointer to context for use by the callback receiver.
100     * info:    Pointer to optional parameter according to event type:
101     *          - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write
102     *            more bytes than indicated by 'size' field and update 'size' if fewer bytes are
103     *            written.
104     *          - EVENT_UNDERRUN: unused.
105     *          - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining.
106     *          - EVENT_MARKER: pointer to const uint32_t containing the marker position in frames.
107     *          - EVENT_NEW_POS: pointer to const uint32_t containing the new position in frames.
108     *          - EVENT_BUFFER_END: unused.
109     *          - EVENT_NEW_IAUDIOTRACK: unused.
110     */
111
112    typedef void (*callback_t)(int event, void* user, void *info);
113
114    /* Returns the minimum frame count required for the successful creation of
115     * an AudioTrack object.
116     * Returned status (from utils/Errors.h) can be:
117     *  - NO_ERROR: successful operation
118     *  - NO_INIT: audio server or audio hardware not initialized
119     */
120
121    static status_t getMinFrameCount(size_t* frameCount,
122                                     audio_stream_type_t streamType,
123                                     uint32_t sampleRate);
124
125    /* How data is transferred to AudioTrack
126     */
127    enum transfer_type {
128        TRANSFER_DEFAULT,   // not specified explicitly; determine from the other parameters
129        TRANSFER_CALLBACK,  // callback EVENT_MORE_DATA
130        TRANSFER_OBTAIN,    // FIXME deprecated: call obtainBuffer() and releaseBuffer()
131        TRANSFER_SYNC,      // synchronous write()
132        TRANSFER_SHARED,    // shared memory
133    };
134
135    /* Constructs an uninitialized AudioTrack. No connection with
136     * AudioFlinger takes place.  Use set() after this.
137     */
138                        AudioTrack();
139
140    /* Creates an AudioTrack object and registers it with AudioFlinger.
141     * Once created, the track needs to be started before it can be used.
142     * Unspecified values are set to appropriate default values.
143     * With this constructor, the track is configured for streaming mode.
144     * Data to be rendered is supplied by write() or by the callback EVENT_MORE_DATA.
145     * Intermixing a combination of write() and non-ignored EVENT_MORE_DATA is not allowed.
146     *
147     * Parameters:
148     *
149     * streamType:         Select the type of audio stream this track is attached to
150     *                     (e.g. AUDIO_STREAM_MUSIC).
151     * sampleRate:         Data source sampling rate in Hz.
152     * format:             Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed
153     *                     16 bits per sample).
154     * channelMask:        Channel mask.
155     * frameCount:         Minimum size of track PCM buffer in frames. This defines the
156     *                     application's contribution to the
157     *                     latency of the track. The actual size selected by the AudioTrack could be
158     *                     larger if the requested size is not compatible with current audio HAL
159     *                     configuration.  Zero means to use a default value.
160     * flags:              See comments on audio_output_flags_t in <system/audio.h>.
161     * cbf:                Callback function. If not null, this function is called periodically
162     *                     to provide new data and inform of marker, position updates, etc.
163     * user:               Context for use by the callback receiver.
164     * notificationFrames: The callback function is called each time notificationFrames PCM
165     *                     frames have been consumed from track input buffer.
166     *                     This is expressed in units of frames at the initial source sample rate.
167     * sessionId:          Specific session ID, or zero to use default.
168     * transferType:       How data is transferred to AudioTrack.
169     * threadCanCallJava:  Not present in parameter list, and so is fixed at false.
170     */
171
172                        AudioTrack( audio_stream_type_t streamType,
173                                    uint32_t sampleRate  = 0,
174                                    audio_format_t format = AUDIO_FORMAT_DEFAULT,
175                                    audio_channel_mask_t channelMask = 0,
176                                    int frameCount       = 0,
177                                    audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
178                                    callback_t cbf       = NULL,
179                                    void* user           = NULL,
180                                    int notificationFrames = 0,
181                                    int sessionId        = 0,
182                                    transfer_type transferType = TRANSFER_DEFAULT,
183                                    const audio_offload_info_t *offloadInfo = NULL);
184
185    /* Creates an audio track and registers it with AudioFlinger.
186     * With this constructor, the track is configured for static buffer mode.
187     * The format must not be 8-bit linear PCM.
188     * Data to be rendered is passed in a shared memory buffer
189     * identified by the argument sharedBuffer, which must be non-0.
190     * The memory should be initialized to the desired data before calling start().
191     * The write() method is not supported in this case.
192     * It is recommended to pass a callback function to be notified of playback end by an
193     * EVENT_UNDERRUN event.
194     */
195
196                        AudioTrack( audio_stream_type_t streamType,
197                                    uint32_t sampleRate = 0,
198                                    audio_format_t format = AUDIO_FORMAT_DEFAULT,
199                                    audio_channel_mask_t channelMask = 0,
200                                    const sp<IMemory>& sharedBuffer = 0,
201                                    audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
202                                    callback_t cbf      = NULL,
203                                    void* user          = NULL,
204                                    int notificationFrames = 0,
205                                    int sessionId       = 0,
206                                    transfer_type transferType = TRANSFER_DEFAULT,
207                                    const audio_offload_info_t *offloadInfo = NULL);
208
209    /* Terminates the AudioTrack and unregisters it from AudioFlinger.
210     * Also destroys all resources associated with the AudioTrack.
211     */
212protected:
213                        virtual ~AudioTrack();
214public:
215
216    /* Initialize an AudioTrack that was created using the AudioTrack() constructor.
217     * Don't call set() more than once, or after the AudioTrack() constructors that take parameters.
218     * Returned status (from utils/Errors.h) can be:
219     *  - NO_ERROR: successful initialization
220     *  - INVALID_OPERATION: AudioTrack is already initialized
221     *  - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...)
222     *  - NO_INIT: audio server or audio hardware not initialized
223     * If sharedBuffer is non-0, the frameCount parameter is ignored and
224     * replaced by the shared buffer's total allocated size in frame units.
225     *
226     * Parameters not listed in the AudioTrack constructors above:
227     *
228     * threadCanCallJava:  Whether callbacks are made from an attached thread and thus can call JNI.
229     */
230            status_t    set(audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT,
231                            uint32_t sampleRate = 0,
232                            audio_format_t format = AUDIO_FORMAT_DEFAULT,
233                            audio_channel_mask_t channelMask = 0,
234                            int frameCount      = 0,
235                            audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
236                            callback_t cbf      = NULL,
237                            void* user          = NULL,
238                            int notificationFrames = 0,
239                            const sp<IMemory>& sharedBuffer = 0,
240                            bool threadCanCallJava = false,
241                            int sessionId       = 0,
242                            transfer_type transferType = TRANSFER_DEFAULT,
243                            const audio_offload_info_t *offloadInfo = NULL);
244
245    /* Result of constructing the AudioTrack. This must be checked
246     * before using any AudioTrack API (except for set()), because using
247     * an uninitialized AudioTrack produces undefined results.
248     * See set() method above for possible return codes.
249     */
250            status_t    initCheck() const   { return mStatus; }
251
252    /* Returns this track's estimated latency in milliseconds.
253     * This includes the latency due to AudioTrack buffer size, AudioMixer (if any)
254     * and audio hardware driver.
255     */
256            uint32_t    latency() const     { return mLatency; }
257
258    /* getters, see constructors and set() */
259
260            audio_stream_type_t streamType() const { return mStreamType; }
261            audio_format_t format() const   { return mFormat; }
262
263    /* Return frame size in bytes, which for linear PCM is
264     * channelCount * (bit depth per channel / 8).
265     * channelCount is determined from channelMask, and bit depth comes from format.
266     * For non-linear formats, the frame size is typically 1 byte.
267     */
268            size_t      frameSize() const   { return mFrameSize; }
269
270            uint32_t    channelCount() const { return mChannelCount; }
271            uint32_t    frameCount() const  { return mFrameCount; }
272
273    /* Return the static buffer specified in constructor or set(), or 0 for streaming mode */
274            sp<IMemory> sharedBuffer() const { return mSharedBuffer; }
275
276    /* After it's created the track is not active. Call start() to
277     * make it active. If set, the callback will start being called.
278     * If the track was previously paused, volume is ramped up over the first mix buffer.
279     */
280            void        start();
281
282    /* Stop a track.
283     * In static buffer mode, the track is stopped immediately.
284     * In streaming mode, the callback will cease being called.  Note that obtainBuffer() still
285     * works and will fill up buffers until the pool is exhausted, and then will return WOULD_BLOCK.
286     * In streaming mode the stop does not occur immediately: any data remaining in the buffer
287     * is first drained, mixed, and output, and only then is the track marked as stopped.
288     */
289            void        stop();
290            bool        stopped() const;
291
292    /* Flush a stopped or paused track. All previously buffered data is discarded immediately.
293     * This has the effect of draining the buffers without mixing or output.
294     * Flush is intended for streaming mode, for example before switching to non-contiguous content.
295     * This function is a no-op if the track is not stopped or paused, or uses a static buffer.
296     */
297            void        flush();
298
299    /* Pause a track. After pause, the callback will cease being called and
300     * obtainBuffer returns WOULD_BLOCK. Note that obtainBuffer() still works
301     * and will fill up buffers until the pool is exhausted.
302     * Volume is ramped down over the next mix buffer following the pause request,
303     * and then the track is marked as paused.  It can be resumed with ramp up by start().
304     */
305            void        pause();
306
307    /* Set volume for this track, mostly used for games' sound effects
308     * left and right volumes. Levels must be >= 0.0 and <= 1.0.
309     * This is the older API.  New applications should use setVolume(float) when possible.
310     */
311            status_t    setVolume(float left, float right);
312
313    /* Set volume for all channels.  This is the preferred API for new applications,
314     * especially for multi-channel content.
315     */
316            status_t    setVolume(float volume);
317
318    /* Set the send level for this track. An auxiliary effect should be attached
319     * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0.
320     */
321            status_t    setAuxEffectSendLevel(float level);
322            void        getAuxEffectSendLevel(float* level) const;
323
324    /* Set source sample rate for this track in Hz, mostly used for games' sound effects
325     */
326            status_t    setSampleRate(uint32_t sampleRate);
327
328    /* Return current source sample rate in Hz, or 0 if unknown */
329            uint32_t    getSampleRate() const;
330
331    /* Enables looping and sets the start and end points of looping.
332     * Only supported for static buffer mode.
333     *
334     * FIXME The comments below are for the new planned interpretation which is not yet implemented.
335     * Currently the legacy behavior is still implemented, where loopStart and loopEnd
336     * are in wrapping (overflow) frame units like the return value of getPosition().
337     * The plan is to fix all callers to use the new version at same time implementation changes.
338     *
339     * Parameters:
340     *
341     * loopStart:   loop start in frames relative to start of buffer.
342     * loopEnd:     loop end in frames relative to start of buffer.
343     * loopCount:   number of loops to execute. Calling setLoop() with loopCount == 0 cancels any
344     *              pending or active loop. loopCount == -1 means infinite looping.
345     *
346     * For proper operation the following condition must be respected:
347     *      loopCount != 0 implies 0 <= loopStart < loopEnd <= frameCount().
348     *
349     * If the loop period (loopEnd - loopStart) is too small for the implementation to support,
350     * setLoop() will return BAD_VALUE.  loopCount must be >= -1.
351     *
352     */
353            status_t    setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount);
354
355    /* Sets marker position. When playback reaches the number of frames specified, a callback with
356     * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker
357     * notification callback.  To set a marker at a position which would compute as 0,
358     * a workaround is to the set the marker at a nearby position such as ~0 or 1.
359     * If the AudioTrack has been opened with no callback function associated, the operation will
360     * fail.
361     *
362     * Parameters:
363     *
364     * marker:   marker position expressed in wrapping (overflow) frame units,
365     *           like the return value of getPosition().
366     *
367     * Returned status (from utils/Errors.h) can be:
368     *  - NO_ERROR: successful operation
369     *  - INVALID_OPERATION: the AudioTrack has no callback installed.
370     */
371            status_t    setMarkerPosition(uint32_t marker);
372            status_t    getMarkerPosition(uint32_t *marker) const;
373
374    /* Sets position update period. Every time the number of frames specified has been played,
375     * a callback with event type EVENT_NEW_POS is called.
376     * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification
377     * callback.
378     * If the AudioTrack has been opened with no callback function associated, the operation will
379     * fail.
380     * Extremely small values may be rounded up to a value the implementation can support.
381     *
382     * Parameters:
383     *
384     * updatePeriod:  position update notification period expressed in frames.
385     *
386     * Returned status (from utils/Errors.h) can be:
387     *  - NO_ERROR: successful operation
388     *  - INVALID_OPERATION: the AudioTrack has no callback installed.
389     */
390            status_t    setPositionUpdatePeriod(uint32_t updatePeriod);
391            status_t    getPositionUpdatePeriod(uint32_t *updatePeriod) const;
392
393    /* Sets playback head position.
394     * Only supported for static buffer mode.
395     *
396     * FIXME The comments below are for the new planned interpretation which is not yet implemented.
397     * Currently the legacy behavior is still implemented, where the new position
398     * is in wrapping (overflow) frame units like the return value of getPosition().
399     * The plan is to fix all callers to use the new version at same time implementation changes.
400     *
401     * Parameters:
402     *
403     * position:  New playback head position in frames relative to start of buffer.
404     *            0 <= position <= frameCount().  Note that end of buffer is permitted,
405     *            but will result in an immediate underrun if started.
406     *
407     * Returned status (from utils/Errors.h) can be:
408     *  - NO_ERROR: successful operation
409     *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
410     *  - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack
411     *               buffer
412     */
413            status_t    setPosition(uint32_t position);
414
415    /* Return the total number of frames played since playback start.
416     * The counter will wrap (overflow) periodically, e.g. every ~27 hours at 44.1 kHz.
417     * It is reset to zero by flush(), reload(), and stop().
418     *
419     * Parameters:
420     *
421     *  position:  Address where to return play head position.
422     *
423     * Returned status (from utils/Errors.h) can be:
424     *  - NO_ERROR: successful operation
425     *  - BAD_VALUE:  position is NULL
426     */
427            status_t    getPosition(uint32_t *position) const;
428
429    /* For static buffer mode only, this returns the current playback position in frames
430     * relative to start of buffer.  It is analogous to the new API for
431     * setLoop() and setPosition().  After underrun, the position will be at end of buffer.
432     */
433            status_t    getBufferPosition(uint32_t *position);
434
435    /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids
436     * rewriting the buffer before restarting playback after a stop.
437     * This method must be called with the AudioTrack in paused or stopped state.
438     * Not allowed in streaming mode.
439     *
440     * Returned status (from utils/Errors.h) can be:
441     *  - NO_ERROR: successful operation
442     *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
443     */
444            status_t    reload();
445
446    /* Returns a handle on the audio output used by this AudioTrack.
447     *
448     * Parameters:
449     *  none.
450     *
451     * Returned value:
452     *  handle on audio hardware output
453     */
454            audio_io_handle_t    getOutput();
455
456    /* Returns the unique session ID associated with this track.
457     *
458     * Parameters:
459     *  none.
460     *
461     * Returned value:
462     *  AudioTrack session ID.
463     */
464            int    getSessionId() const { return mSessionId; }
465
466    /* Attach track auxiliary output to specified effect. Use effectId = 0
467     * to detach track from effect.
468     *
469     * Parameters:
470     *
471     * effectId:  effectId obtained from AudioEffect::id().
472     *
473     * Returned status (from utils/Errors.h) can be:
474     *  - NO_ERROR: successful operation
475     *  - INVALID_OPERATION: the effect is not an auxiliary effect.
476     *  - BAD_VALUE: The specified effect ID is invalid
477     */
478            status_t    attachAuxEffect(int effectId);
479
480    /* Obtains a buffer of up to "audioBuffer->frameCount" empty slots for frames.
481     * After filling these slots with data, the caller should release them with releaseBuffer().
482     * If the track buffer is not full, obtainBuffer() returns as many contiguous
483     * [empty slots for] frames as are available immediately.
484     * If the track buffer is full and track is stopped, obtainBuffer() returns WOULD_BLOCK
485     * regardless of the value of waitCount.
486     * If the track buffer is full and track is not stopped, obtainBuffer() blocks with a
487     * maximum timeout based on waitCount; see chart below.
488     * Buffers will be returned until the pool
489     * is exhausted, at which point obtainBuffer() will either block
490     * or return WOULD_BLOCK depending on the value of the "waitCount"
491     * parameter.
492     * Each sample is 16-bit signed PCM.
493     *
494     * obtainBuffer() and releaseBuffer() are deprecated for direct use by applications,
495     * which should use write() or callback EVENT_MORE_DATA instead.
496     *
497     * Interpretation of waitCount:
498     *  +n  limits wait time to n * WAIT_PERIOD_MS,
499     *  -1  causes an (almost) infinite wait time,
500     *   0  non-blocking.
501     *
502     * Buffer fields
503     * On entry:
504     *  frameCount  number of frames requested
505     * After error return:
506     *  frameCount  0
507     *  size        0
508     *  raw         undefined
509     * After successful return:
510     *  frameCount  actual number of frames available, <= number requested
511     *  size        actual number of bytes available
512     *  raw         pointer to the buffer
513     */
514
515    /* FIXME Deprecated public API for TRANSFER_OBTAIN mode */
516            status_t    obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
517                                __attribute__((__deprecated__));
518
519private:
520    /* New internal API
521     * If nonContig is non-NULL, it is an output parameter that will be set to the number of
522     * additional non-contiguous frames that are available immediately.
523     * FIXME We could pass an array of Buffers instead of only one Buffer to obtainBuffer(),
524     * in case the requested amount of frames is in two or more non-contiguous regions.
525     * FIXME requested and elapsed are both relative times.  Consider changing to absolute time.
526     */
527            status_t    obtainBuffer(Buffer* audioBuffer, const struct timespec *requested,
528                                     struct timespec *elapsed = NULL, size_t *nonContig = NULL);
529public:
530
531//EL_FIXME to be reconciled with new obtainBuffer() return codes and control block proxy
532//            enum {
533//            NO_MORE_BUFFERS = 0x80000001,   // same name in AudioFlinger.h, ok to be different value
534//            TEAR_DOWN       = 0x80000002,
535//            STOPPED = 1,
536//            STREAM_END_WAIT,
537//            STREAM_END
538//        };
539
540    /* Release a filled buffer of "audioBuffer->frameCount" frames for AudioFlinger to process. */
541    // FIXME make private when obtainBuffer() for TRANSFER_OBTAIN is removed
542            void        releaseBuffer(Buffer* audioBuffer);
543
544    /* As a convenience we provide a write() interface to the audio buffer.
545     * Input parameter 'size' is in byte units.
546     * This is implemented on top of obtainBuffer/releaseBuffer. For best
547     * performance use callbacks. Returns actual number of bytes written >= 0,
548     * or one of the following negative status codes:
549     *      INVALID_OPERATION   AudioTrack is configured for shared buffer mode
550     *      BAD_VALUE           size is invalid
551     *      WOULD_BLOCK         when obtainBuffer() returns same, or
552     *                          AudioTrack was stopped during the write
553     *      or any other error code returned by IAudioTrack::start() or restoreTrack_l().
554     * Not supported for static buffer mode.
555     */
556            ssize_t     write(const void* buffer, size_t size);
557
558    /*
559     * Dumps the state of an audio track.
560     */
561            status_t    dump(int fd, const Vector<String16>& args) const;
562
563    /*
564     * Return the total number of frames which AudioFlinger desired but were unavailable,
565     * and thus which resulted in an underrun.  Reset to zero by stop().
566     */
567            uint32_t    getUnderrunFrames() const;
568
569    /* Get the flags */
570            audio_output_flags_t getFlags() const { return mFlags; }
571
572    /* Set parameters - only possible when using direct output */
573            status_t    setParameters(const String8& keyValuePairs);
574
575    /* Get parameters */
576            String8     getParameters(const String8& keys);
577
578protected:
579    /* copying audio tracks is not allowed */
580                        AudioTrack(const AudioTrack& other);
581            AudioTrack& operator = (const AudioTrack& other);
582
583    /* a small internal class to handle the callback */
584    class AudioTrackThread : public Thread
585    {
586    public:
587        AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false);
588
589        // Do not call Thread::requestExitAndWait() without first calling requestExit().
590        // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough.
591        virtual void        requestExit();
592
593                void        pause();    // suspend thread from execution at next loop boundary
594                void        resume();   // allow thread to execute, if not requested to exit
595                void        pauseConditional();
596                                        // like pause(), but only if prior resume() wasn't latched
597
598    private:
599        friend class AudioTrack;
600        virtual bool        threadLoop();
601        AudioTrack&         mReceiver;
602        virtual ~AudioTrackThread();
603        Mutex               mMyLock;    // Thread::mLock is private
604        Condition           mMyCond;    // Thread::mThreadExitedCondition is private
605        bool                mPaused;    // whether thread is currently paused
606        bool                mResumeLatch;   // whether next pauseConditional() will be a nop
607    };
608
609            // body of AudioTrackThread::threadLoop()
610            // returns the maximum amount of time before we would like to run again, where:
611            //      0           immediately
612            //      > 0         no later than this many nanoseconds from now
613            //      NS_WHENEVER still active but no particular deadline
614            //      NS_INACTIVE inactive so don't run again until re-started
615            //      NS_NEVER    never again
616            static const nsecs_t NS_WHENEVER = -1, NS_INACTIVE = -2, NS_NEVER = -3;
617            nsecs_t processAudioBuffer(const sp<AudioTrackThread>& thread);
618            status_t processStreamEnd(int32_t waitCount);
619
620
621            // caller must hold lock on mLock for all _l methods
622
623            status_t createTrack_l(audio_stream_type_t streamType,
624                                 uint32_t sampleRate,
625                                 audio_format_t format,
626                                 size_t frameCount,
627                                 audio_output_flags_t flags,
628                                 const sp<IMemory>& sharedBuffer,
629                                 audio_io_handle_t output,
630                                 size_t epoch);
631
632            // can only be called when mState != STATE_ACTIVE
633            void flush_l();
634
635            void setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);
636            audio_io_handle_t getOutput_l();
637
638            status_t getPosition_l(uint32_t *position);
639
640            // FIXME enum is faster than strcmp() for parameter 'from'
641            status_t restoreTrack_l(const char *from);
642
643    // may be changed if IAudioTrack is re-created
644    sp<IAudioTrack>         mAudioTrack;
645    sp<IMemory>             mCblkMemory;
646    audio_track_cblk_t*     mCblk;                  // re-load after mLock.unlock()
647
648    sp<AudioTrackThread>    mAudioTrackThread;
649    float                   mVolume[2];
650    float                   mSendLevel;
651    uint32_t                mSampleRate;
652    size_t                  mFrameCount;            // corresponds to current IAudioTrack
653    size_t                  mReqFrameCount;         // frame count to request the next time a new
654                                                    // IAudioTrack is needed
655
656
657    // constant after constructor or set()
658    audio_format_t          mFormat;                // as requested by client, not forced to 16-bit
659    audio_stream_type_t     mStreamType;
660    uint32_t                mChannelCount;
661    audio_channel_mask_t    mChannelMask;
662    transfer_type           mTransfer;
663
664    // mFrameSize is equal to mFrameSizeAF for non-PCM or 16-bit PCM data.  For 8-bit PCM data, it's
665    // twice as large as mFrameSize because data is expanded to 16-bit before it's stored in buffer.
666    size_t                  mFrameSize;             // app-level frame size
667    size_t                  mFrameSizeAF;           // AudioFlinger frame size
668
669    status_t                mStatus;
670
671    // can change dynamically when IAudioTrack invalidated
672    uint32_t                mLatency;               // in ms
673
674    // Indicates the current track state.  Protected by mLock.
675    enum State {
676        STATE_ACTIVE,
677        STATE_STOPPED,
678        STATE_PAUSED,
679        STATE_FLUSHED,
680    }                       mState;
681
682    callback_t              mCbf;                   // callback handler for events, or NULL
683    void*                   mUserData;              // for client callback handler
684
685    // for notification APIs
686    uint32_t                mNotificationFramesReq; // requested number of frames between each
687                                                    // notification callback,
688                                                    // at initial source sample rate
689    uint32_t                mNotificationFramesAct; // actual number of frames between each
690                                                    // notification callback,
691                                                    // at initial source sample rate
692    bool                    mRefreshRemaining;      // processAudioBuffer() should refresh next 2
693
694    // These are private to processAudioBuffer(), and are not protected by a lock
695    uint32_t                mRemainingFrames;       // number of frames to request in obtainBuffer()
696    bool                    mRetryOnPartialBuffer;  // sleep and retry after partial obtainBuffer()
697    int                     mObservedSequence;      // last observed value of mSequence
698
699    sp<IMemory>             mSharedBuffer;
700    uint32_t                mLoopPeriod;            // in frames, zero means looping is disabled
701    uint32_t                mMarkerPosition;        // in wrapping (overflow) frame units
702    bool                    mMarkerReached;
703    uint32_t                mNewPosition;           // in frames
704    uint32_t                mUpdatePeriod;          // in frames, zero means no EVENT_NEW_POS
705
706    audio_output_flags_t    mFlags;
707    int                     mSessionId;
708    int                     mAuxEffectId;
709
710    mutable Mutex           mLock;
711
712    bool                    mIsTimed;
713    int                     mPreviousPriority;          // before start()
714    SchedPolicy             mPreviousSchedulingGroup;
715    bool                    mAwaitBoost;    // thread should wait for priority boost before running
716
717    // The proxy should only be referenced while a lock is held because the proxy isn't
718    // multi-thread safe, especially the SingleStateQueue part of the proxy.
719    // An exception is that a blocking ClientProxy::obtainBuffer() may be called without a lock,
720    // provided that the caller also holds an extra reference to the proxy and shared memory to keep
721    // them around in case they are replaced during the obtainBuffer().
722    sp<StaticAudioTrackClientProxy> mStaticProxy;   // for type safety only
723    sp<AudioTrackClientProxy>       mProxy;         // primary owner of the memory
724
725    bool                    mInUnderrun;            // whether track is currently in underrun state
726
727private:
728    class DeathNotifier : public IBinder::DeathRecipient {
729    public:
730        DeathNotifier(AudioTrack* audioTrack) : mAudioTrack(audioTrack) { }
731    protected:
732        virtual void        binderDied(const wp<IBinder>& who);
733    private:
734        const wp<AudioTrack> mAudioTrack;
735    };
736
737    sp<DeathNotifier>       mDeathNotifier;
738    uint32_t                mSequence;              // incremented for each new IAudioTrack attempt
739};
740
741class TimedAudioTrack : public AudioTrack
742{
743public:
744    TimedAudioTrack();
745
746    /* allocate a shared memory buffer that can be passed to queueTimedBuffer */
747    status_t allocateTimedBuffer(size_t size, sp<IMemory>* buffer);
748
749    /* queue a buffer obtained via allocateTimedBuffer for playback at the
750       given timestamp.  PTS units are microseconds on the media time timeline.
751       The media time transform (set with setMediaTimeTransform) set by the
752       audio producer will handle converting from media time to local time
753       (perhaps going through the common time timeline in the case of
754       synchronized multiroom audio case) */
755    status_t queueTimedBuffer(const sp<IMemory>& buffer, int64_t pts);
756
757    /* define a transform between media time and either common time or
758       local time */
759    enum TargetTimeline {LOCAL_TIME, COMMON_TIME};
760    status_t setMediaTimeTransform(const LinearTransform& xform,
761                                   TargetTimeline target);
762};
763
764}; // namespace android
765
766#endif // ANDROID_AUDIOTRACK_H
767