AudioTrack.h revision 6dc365f0d5a92084517f0c3846e4f07fc7206bab
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/AudioTimestamp.h>
23#include <media/IAudioTrack.h>
24#include <utils/threads.h>
25
26namespace android {
27
28// ----------------------------------------------------------------------------
29
30class audio_track_cblk_t;
31class AudioTrackClientProxy;
32class StaticAudioTrackClientProxy;
33
34// ----------------------------------------------------------------------------
35
36class AudioTrack : public RefBase
37{
38public:
39    enum channel_index {
40        MONO   = 0,
41        LEFT   = 0,
42        RIGHT  = 1
43    };
44
45    /* Events used by AudioTrack callback function (callback_t).
46     * Keep in sync with frameworks/base/media/java/android/media/AudioTrack.java NATIVE_EVENT_*.
47     */
48    enum event_type {
49        EVENT_MORE_DATA = 0,        // Request to write more data to buffer.
50                                    // If this event is delivered but the callback handler
51                                    // does not want to write more data, the handler must explicitly
52                                    // ignore the event by setting frameCount to zero.
53        EVENT_UNDERRUN = 1,         // Buffer underrun occurred.
54        EVENT_LOOP_END = 2,         // Sample loop end was reached; playback restarted from
55                                    // loop start if loop count was not 0.
56        EVENT_MARKER = 3,           // Playback head is at the specified marker position
57                                    // (See setMarkerPosition()).
58        EVENT_NEW_POS = 4,          // Playback head is at a new position
59                                    // (See setPositionUpdatePeriod()).
60        EVENT_BUFFER_END = 5,       // Playback head is at the end of the buffer.
61                                    // Not currently used by android.media.AudioTrack.
62        EVENT_NEW_IAUDIOTRACK = 6,  // IAudioTrack was re-created, either due to re-routing and
63                                    // voluntary invalidation by mediaserver, or mediaserver crash.
64        EVENT_STREAM_END = 7,       // Sent after all the buffers queued in AF and HW are played
65                                    // back (after stop is called)
66        EVENT_NEW_TIMESTAMP = 8,    // Delivered periodically and when there's a significant change
67                                    // in the mapping from frame position to presentation time.
68                                    // See AudioTimestamp for the information included with event.
69    };
70
71    /* Client should declare Buffer on the stack and pass address to obtainBuffer()
72     * and releaseBuffer().  See also callback_t for EVENT_MORE_DATA.
73     */
74
75    class Buffer
76    {
77    public:
78        // FIXME use m prefix
79        size_t      frameCount;   // number of sample frames corresponding to size;
80                                  // on input it is the number of frames desired,
81                                  // on output is the number of frames actually filled
82                                  // (currently ignored, but will make the primary field in future)
83
84        size_t      size;         // input/output in bytes == frameCount * frameSize
85                                  // on output is the number of bytes actually filled
86                                  // FIXME this is redundant with respect to frameCount,
87                                  // and TRANSFER_OBTAIN mode is broken for 8-bit data
88                                  // since we don't define the frame format
89
90        union {
91            void*       raw;
92            short*      i16;      // signed 16-bit
93            int8_t*     i8;       // unsigned 8-bit, offset by 0x80
94        };
95    };
96
97    /* As a convenience, if a callback is supplied, a handler thread
98     * is automatically created with the appropriate priority. This thread
99     * invokes the callback when a new buffer becomes available or various conditions occur.
100     * Parameters:
101     *
102     * event:   type of event notified (see enum AudioTrack::event_type).
103     * user:    Pointer to context for use by the callback receiver.
104     * info:    Pointer to optional parameter according to event type:
105     *          - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write
106     *            more bytes than indicated by 'size' field and update 'size' if fewer bytes are
107     *            written.
108     *          - EVENT_UNDERRUN: unused.
109     *          - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining.
110     *          - EVENT_MARKER: pointer to const uint32_t containing the marker position in frames.
111     *          - EVENT_NEW_POS: pointer to const uint32_t containing the new position in frames.
112     *          - EVENT_BUFFER_END: unused.
113     *          - EVENT_NEW_IAUDIOTRACK: unused.
114     *          - EVENT_STREAM_END: unused.
115     *          - EVENT_NEW_TIMESTAMP: pointer to const AudioTimestamp.
116     */
117
118    typedef void (*callback_t)(int event, void* user, void *info);
119
120    /* Returns the minimum frame count required for the successful creation of
121     * an AudioTrack object.
122     * Returned status (from utils/Errors.h) can be:
123     *  - NO_ERROR: successful operation
124     *  - NO_INIT: audio server or audio hardware not initialized
125     *  - BAD_VALUE: unsupported configuration
126     */
127
128    static status_t getMinFrameCount(size_t* frameCount,
129                                     audio_stream_type_t streamType,
130                                     uint32_t sampleRate);
131
132    /* How data is transferred to AudioTrack
133     */
134    enum transfer_type {
135        TRANSFER_DEFAULT,   // not specified explicitly; determine from the other parameters
136        TRANSFER_CALLBACK,  // callback EVENT_MORE_DATA
137        TRANSFER_OBTAIN,    // FIXME deprecated: call obtainBuffer() and releaseBuffer()
138        TRANSFER_SYNC,      // synchronous write()
139        TRANSFER_SHARED,    // shared memory
140    };
141
142    /* Constructs an uninitialized AudioTrack. No connection with
143     * AudioFlinger takes place.  Use set() after this.
144     */
145                        AudioTrack();
146
147    /* Creates an AudioTrack object and registers it with AudioFlinger.
148     * Once created, the track needs to be started before it can be used.
149     * Unspecified values are set to appropriate default values.
150     * With this constructor, the track is configured for streaming mode.
151     * Data to be rendered is supplied by write() or by the callback EVENT_MORE_DATA.
152     * Intermixing a combination of write() and non-ignored EVENT_MORE_DATA is not allowed.
153     *
154     * Parameters:
155     *
156     * streamType:         Select the type of audio stream this track is attached to
157     *                     (e.g. AUDIO_STREAM_MUSIC).
158     * sampleRate:         Data source sampling rate in Hz.
159     * format:             Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed
160     *                     16 bits per sample).
161     * channelMask:        Channel mask.
162     * frameCount:         Minimum size of track PCM buffer in frames. This defines the
163     *                     application's contribution to the
164     *                     latency of the track. The actual size selected by the AudioTrack could be
165     *                     larger if the requested size is not compatible with current audio HAL
166     *                     configuration.  Zero means to use a default value.
167     * flags:              See comments on audio_output_flags_t in <system/audio.h>.
168     * cbf:                Callback function. If not null, this function is called periodically
169     *                     to provide new data and inform of marker, position updates, etc.
170     * user:               Context for use by the callback receiver.
171     * notificationFrames: The callback function is called each time notificationFrames PCM
172     *                     frames have been consumed from track input buffer.
173     *                     This is expressed in units of frames at the initial source sample rate.
174     * sessionId:          Specific session ID, or zero to use default.
175     * transferType:       How data is transferred to AudioTrack.
176     * threadCanCallJava:  Not present in parameter list, and so is fixed at false.
177     */
178
179                        AudioTrack( audio_stream_type_t streamType,
180                                    uint32_t sampleRate,
181                                    audio_format_t format,
182                                    audio_channel_mask_t,
183                                    int frameCount       = 0,
184                                    audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
185                                    callback_t cbf       = NULL,
186                                    void* user           = NULL,
187                                    int notificationFrames = 0,
188                                    int sessionId        = 0,
189                                    transfer_type transferType = TRANSFER_DEFAULT,
190                                    const audio_offload_info_t *offloadInfo = NULL);
191
192    /* Creates an audio track and registers it with AudioFlinger.
193     * With this constructor, the track is configured for static buffer mode.
194     * The format must not be 8-bit linear PCM.
195     * Data to be rendered is passed in a shared memory buffer
196     * identified by the argument sharedBuffer, which must be non-0.
197     * The memory should be initialized to the desired data before calling start().
198     * The write() method is not supported in this case.
199     * It is recommended to pass a callback function to be notified of playback end by an
200     * EVENT_UNDERRUN event.
201     */
202
203                        AudioTrack( audio_stream_type_t streamType,
204                                    uint32_t sampleRate,
205                                    audio_format_t format,
206                                    audio_channel_mask_t channelMask,
207                                    const sp<IMemory>& sharedBuffer,
208                                    audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
209                                    callback_t cbf      = NULL,
210                                    void* user          = NULL,
211                                    int notificationFrames = 0,
212                                    int sessionId       = 0,
213                                    transfer_type transferType = TRANSFER_DEFAULT,
214                                    const audio_offload_info_t *offloadInfo = NULL);
215
216    /* Terminates the AudioTrack and unregisters it from AudioFlinger.
217     * Also destroys all resources associated with the AudioTrack.
218     */
219protected:
220                        virtual ~AudioTrack();
221public:
222
223    /* Initialize an AudioTrack that was created using the AudioTrack() constructor.
224     * Don't call set() more than once, or after the AudioTrack() constructors that take parameters.
225     * Returned status (from utils/Errors.h) can be:
226     *  - NO_ERROR: successful initialization
227     *  - INVALID_OPERATION: AudioTrack is already initialized
228     *  - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...)
229     *  - NO_INIT: audio server or audio hardware not initialized
230     * If sharedBuffer is non-0, the frameCount parameter is ignored and
231     * replaced by the shared buffer's total allocated size in frame units.
232     *
233     * Parameters not listed in the AudioTrack constructors above:
234     *
235     * threadCanCallJava:  Whether callbacks are made from an attached thread and thus can call JNI.
236     */
237            status_t    set(audio_stream_type_t streamType,
238                            uint32_t sampleRate,
239                            audio_format_t format,
240                            audio_channel_mask_t channelMask,
241                            int frameCount      = 0,
242                            audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
243                            callback_t cbf      = NULL,
244                            void* user          = NULL,
245                            int notificationFrames = 0,
246                            const sp<IMemory>& sharedBuffer = 0,
247                            bool threadCanCallJava = false,
248                            int sessionId       = 0,
249                            transfer_type transferType = TRANSFER_DEFAULT,
250                            const audio_offload_info_t *offloadInfo = NULL);
251
252    /* Result of constructing the AudioTrack. This must be checked
253     * before using any AudioTrack API (except for set()), because using
254     * an uninitialized AudioTrack produces undefined results.
255     * See set() method above for possible return codes.
256     */
257            status_t    initCheck() const   { return mStatus; }
258
259    /* Returns this track's estimated latency in milliseconds.
260     * This includes the latency due to AudioTrack buffer size, AudioMixer (if any)
261     * and audio hardware driver.
262     */
263            uint32_t    latency() const     { return mLatency; }
264
265    /* getters, see constructors and set() */
266
267            audio_stream_type_t streamType() const { return mStreamType; }
268            audio_format_t format() const   { return mFormat; }
269
270    /* Return frame size in bytes, which for linear PCM is
271     * channelCount * (bit depth per channel / 8).
272     * channelCount is determined from channelMask, and bit depth comes from format.
273     * For non-linear formats, the frame size is typically 1 byte.
274     */
275            size_t      frameSize() const   { return mFrameSize; }
276
277            uint32_t    channelCount() const { return mChannelCount; }
278            uint32_t    frameCount() const  { return mFrameCount; }
279
280    /* Return the static buffer specified in constructor or set(), or 0 for streaming mode */
281            sp<IMemory> sharedBuffer() const { return mSharedBuffer; }
282
283    /* After it's created the track is not active. Call start() to
284     * make it active. If set, the callback will start being called.
285     * If the track was previously paused, volume is ramped up over the first mix buffer.
286     */
287            status_t        start();
288
289    /* Stop a track.
290     * In static buffer mode, the track is stopped immediately.
291     * In streaming mode, the callback will cease being called.  Note that obtainBuffer() still
292     * works and will fill up buffers until the pool is exhausted, and then will return WOULD_BLOCK.
293     * In streaming mode the stop does not occur immediately: any data remaining in the buffer
294     * is first drained, mixed, and output, and only then is the track marked as stopped.
295     */
296            void        stop();
297            bool        stopped() const;
298
299    /* Flush a stopped or paused track. All previously buffered data is discarded immediately.
300     * This has the effect of draining the buffers without mixing or output.
301     * Flush is intended for streaming mode, for example before switching to non-contiguous content.
302     * This function is a no-op if the track is not stopped or paused, or uses a static buffer.
303     */
304            void        flush();
305
306    /* Pause a track. After pause, the callback will cease being called and
307     * obtainBuffer returns WOULD_BLOCK. Note that obtainBuffer() still works
308     * and will fill up buffers until the pool is exhausted.
309     * Volume is ramped down over the next mix buffer following the pause request,
310     * and then the track is marked as paused.  It can be resumed with ramp up by start().
311     */
312            void        pause();
313
314    /* Set volume for this track, mostly used for games' sound effects
315     * left and right volumes. Levels must be >= 0.0 and <= 1.0.
316     * This is the older API.  New applications should use setVolume(float) when possible.
317     */
318            status_t    setVolume(float left, float right);
319
320    /* Set volume for all channels.  This is the preferred API for new applications,
321     * especially for multi-channel content.
322     */
323            status_t    setVolume(float volume);
324
325    /* Set the send level for this track. An auxiliary effect should be attached
326     * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0.
327     */
328            status_t    setAuxEffectSendLevel(float level);
329            void        getAuxEffectSendLevel(float* level) const;
330
331    /* Set source sample rate for this track in Hz, mostly used for games' sound effects
332     */
333            status_t    setSampleRate(uint32_t sampleRate);
334
335    /* Return current source sample rate in Hz, or 0 if unknown */
336            uint32_t    getSampleRate() const;
337
338    /* Enables looping and sets the start and end points of looping.
339     * Only supported for static buffer mode.
340     *
341     * Parameters:
342     *
343     * loopStart:   loop start in frames relative to start of buffer.
344     * loopEnd:     loop end in frames relative to start of buffer.
345     * loopCount:   number of loops to execute. Calling setLoop() with loopCount == 0 cancels any
346     *              pending or active loop. loopCount == -1 means infinite looping.
347     *
348     * For proper operation the following condition must be respected:
349     *      loopCount != 0 implies 0 <= loopStart < loopEnd <= frameCount().
350     *
351     * If the loop period (loopEnd - loopStart) is too small for the implementation to support,
352     * setLoop() will return BAD_VALUE.  loopCount must be >= -1.
353     *
354     */
355            status_t    setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount);
356
357    /* Sets marker position. When playback reaches the number of frames specified, a callback with
358     * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker
359     * notification callback.  To set a marker at a position which would compute as 0,
360     * a workaround is to the set the marker at a nearby position such as ~0 or 1.
361     * If the AudioTrack has been opened with no callback function associated, the operation will
362     * fail.
363     *
364     * Parameters:
365     *
366     * marker:   marker position expressed in wrapping (overflow) frame units,
367     *           like the return value of getPosition().
368     *
369     * Returned status (from utils/Errors.h) can be:
370     *  - NO_ERROR: successful operation
371     *  - INVALID_OPERATION: the AudioTrack has no callback installed.
372     */
373            status_t    setMarkerPosition(uint32_t marker);
374            status_t    getMarkerPosition(uint32_t *marker) const;
375
376    /* Sets position update period. Every time the number of frames specified has been played,
377     * a callback with event type EVENT_NEW_POS is called.
378     * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification
379     * callback.
380     * If the AudioTrack has been opened with no callback function associated, the operation will
381     * fail.
382     * Extremely small values may be rounded up to a value the implementation can support.
383     *
384     * Parameters:
385     *
386     * updatePeriod:  position update notification period expressed in frames.
387     *
388     * Returned status (from utils/Errors.h) can be:
389     *  - NO_ERROR: successful operation
390     *  - INVALID_OPERATION: the AudioTrack has no callback installed.
391     */
392            status_t    setPositionUpdatePeriod(uint32_t updatePeriod);
393            status_t    getPositionUpdatePeriod(uint32_t *updatePeriod) const;
394
395    /* Sets playback head position.
396     * Only supported for static buffer mode.
397     *
398     * Parameters:
399     *
400     * position:  New playback head position in frames relative to start of buffer.
401     *            0 <= position <= frameCount().  Note that end of buffer is permitted,
402     *            but will result in an immediate underrun if started.
403     *
404     * Returned status (from utils/Errors.h) can be:
405     *  - NO_ERROR: successful operation
406     *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
407     *  - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack
408     *               buffer
409     */
410            status_t    setPosition(uint32_t position);
411
412    /* Return the total number of frames played since playback start.
413     * The counter will wrap (overflow) periodically, e.g. every ~27 hours at 44.1 kHz.
414     * It is reset to zero by flush(), reload(), and stop().
415     *
416     * Parameters:
417     *
418     *  position:  Address where to return play head position.
419     *
420     * Returned status (from utils/Errors.h) can be:
421     *  - NO_ERROR: successful operation
422     *  - BAD_VALUE:  position is NULL
423     */
424            status_t    getPosition(uint32_t *position) const;
425
426    /* For static buffer mode only, this returns the current playback position in frames
427     * relative to start of buffer.  It is analogous to the position units used by
428     * setLoop() and setPosition().  After underrun, the position will be at end of buffer.
429     */
430            status_t    getBufferPosition(uint32_t *position);
431
432    /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids
433     * rewriting the buffer before restarting playback after a stop.
434     * This method must be called with the AudioTrack in paused or stopped state.
435     * Not allowed in streaming mode.
436     *
437     * Returned status (from utils/Errors.h) can be:
438     *  - NO_ERROR: successful operation
439     *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
440     */
441            status_t    reload();
442
443    /* Returns a handle on the audio output used by this AudioTrack.
444     *
445     * Parameters:
446     *  none.
447     *
448     * Returned value:
449     *  handle on audio hardware output
450     */
451            audio_io_handle_t    getOutput();
452
453    /* Returns the unique session ID associated with this track.
454     *
455     * Parameters:
456     *  none.
457     *
458     * Returned value:
459     *  AudioTrack session ID.
460     */
461            int    getSessionId() const { return mSessionId; }
462
463    /* Attach track auxiliary output to specified effect. Use effectId = 0
464     * to detach track from effect.
465     *
466     * Parameters:
467     *
468     * effectId:  effectId obtained from AudioEffect::id().
469     *
470     * Returned status (from utils/Errors.h) can be:
471     *  - NO_ERROR: successful operation
472     *  - INVALID_OPERATION: the effect is not an auxiliary effect.
473     *  - BAD_VALUE: The specified effect ID is invalid
474     */
475            status_t    attachAuxEffect(int effectId);
476
477    /* Obtains a buffer of up to "audioBuffer->frameCount" empty slots for frames.
478     * After filling these slots with data, the caller should release them with releaseBuffer().
479     * If the track buffer is not full, obtainBuffer() returns as many contiguous
480     * [empty slots for] frames as are available immediately.
481     * If the track buffer is full and track is stopped, obtainBuffer() returns WOULD_BLOCK
482     * regardless of the value of waitCount.
483     * If the track buffer is full and track is not stopped, obtainBuffer() blocks with a
484     * maximum timeout based on waitCount; see chart below.
485     * Buffers will be returned until the pool
486     * is exhausted, at which point obtainBuffer() will either block
487     * or return WOULD_BLOCK depending on the value of the "waitCount"
488     * parameter.
489     * Each sample is 16-bit signed PCM.
490     *
491     * obtainBuffer() and releaseBuffer() are deprecated for direct use by applications,
492     * which should use write() or callback EVENT_MORE_DATA instead.
493     *
494     * Interpretation of waitCount:
495     *  +n  limits wait time to n * WAIT_PERIOD_MS,
496     *  -1  causes an (almost) infinite wait time,
497     *   0  non-blocking.
498     *
499     * Buffer fields
500     * On entry:
501     *  frameCount  number of frames requested
502     * After error return:
503     *  frameCount  0
504     *  size        0
505     *  raw         undefined
506     * After successful return:
507     *  frameCount  actual number of frames available, <= number requested
508     *  size        actual number of bytes available
509     *  raw         pointer to the buffer
510     */
511
512    /* FIXME Deprecated public API for TRANSFER_OBTAIN mode */
513            status_t    obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
514                                __attribute__((__deprecated__));
515
516private:
517    /* If nonContig is non-NULL, it is an output parameter that will be set to the number of
518     * additional non-contiguous frames that are available immediately.
519     * FIXME We could pass an array of Buffers instead of only one Buffer to obtainBuffer(),
520     * in case the requested amount of frames is in two or more non-contiguous regions.
521     * FIXME requested and elapsed are both relative times.  Consider changing to absolute time.
522     */
523            status_t    obtainBuffer(Buffer* audioBuffer, const struct timespec *requested,
524                                     struct timespec *elapsed = NULL, size_t *nonContig = NULL);
525public:
526
527//EL_FIXME to be reconciled with new obtainBuffer() return codes and control block proxy
528//            enum {
529//            NO_MORE_BUFFERS = 0x80000001,   // same name in AudioFlinger.h, ok to be different value
530//            TEAR_DOWN       = 0x80000002,
531//            STOPPED = 1,
532//            STREAM_END_WAIT,
533//            STREAM_END
534//        };
535
536    /* Release a filled buffer of "audioBuffer->frameCount" frames for AudioFlinger to process. */
537    // FIXME make private when obtainBuffer() for TRANSFER_OBTAIN is removed
538            void        releaseBuffer(Buffer* audioBuffer);
539
540    /* As a convenience we provide a write() interface to the audio buffer.
541     * Input parameter 'size' is in byte units.
542     * This is implemented on top of obtainBuffer/releaseBuffer. For best
543     * performance use callbacks. Returns actual number of bytes written >= 0,
544     * or one of the following negative status codes:
545     *      INVALID_OPERATION   AudioTrack is configured for static buffer or streaming mode
546     *      BAD_VALUE           size is invalid
547     *      WOULD_BLOCK         when obtainBuffer() returns same, or
548     *                          AudioTrack was stopped during the write
549     *      or any other error code returned by IAudioTrack::start() or restoreTrack_l().
550     */
551            ssize_t     write(const void* buffer, size_t size);
552
553    /*
554     * Dumps the state of an audio track.
555     */
556            status_t    dump(int fd, const Vector<String16>& args) const;
557
558    /*
559     * Return the total number of frames which AudioFlinger desired but were unavailable,
560     * and thus which resulted in an underrun.  Reset to zero by stop().
561     */
562            uint32_t    getUnderrunFrames() const;
563
564    /* Get the flags */
565            audio_output_flags_t getFlags() const { return mFlags; }
566
567    /* Set parameters - only possible when using direct output */
568            status_t    setParameters(const String8& keyValuePairs);
569
570    /* Get parameters */
571            String8     getParameters(const String8& keys);
572
573    /* Poll for a timestamp on demand.
574     * Use if EVENT_NEW_TIMESTAMP is not delivered often enough for your needs,
575     * or if you need to get the most recent timestamp outside of the event callback handler.
576     * Caution: calling this method too often may be inefficient;
577     * if you need a high resolution mapping between frame position and presentation time,
578     * consider implementing that at application level, based on the low resolution timestamps.
579     * Returns NO_ERROR if timestamp is valid.
580     */
581            status_t    getTimestamp(AudioTimestamp& timestamp);
582
583protected:
584    /* copying audio tracks is not allowed */
585                        AudioTrack(const AudioTrack& other);
586            AudioTrack& operator = (const AudioTrack& other);
587
588    /* a small internal class to handle the callback */
589    class AudioTrackThread : public Thread
590    {
591    public:
592        AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false);
593
594        // Do not call Thread::requestExitAndWait() without first calling requestExit().
595        // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough.
596        virtual void        requestExit();
597
598                void        pause();    // suspend thread from execution at next loop boundary
599                void        resume();   // allow thread to execute, if not requested to exit
600                void        pauseConditional();
601                                        // like pause(), but only if prior resume() wasn't latched
602
603    private:
604        friend class AudioTrack;
605        virtual bool        threadLoop();
606        AudioTrack&         mReceiver;
607        virtual ~AudioTrackThread();
608        Mutex               mMyLock;    // Thread::mLock is private
609        Condition           mMyCond;    // Thread::mThreadExitedCondition is private
610        bool                mPaused;    // whether thread is currently paused
611        bool                mResumeLatch;   // whether next pauseConditional() will be a nop
612    };
613
614            // body of AudioTrackThread::threadLoop()
615            // returns the maximum amount of time before we would like to run again, where:
616            //      0           immediately
617            //      > 0         no later than this many nanoseconds from now
618            //      NS_WHENEVER still active but no particular deadline
619            //      NS_INACTIVE inactive so don't run again until re-started
620            //      NS_NEVER    never again
621            static const nsecs_t NS_WHENEVER = -1, NS_INACTIVE = -2, NS_NEVER = -3;
622            nsecs_t processAudioBuffer(const sp<AudioTrackThread>& thread);
623            status_t processStreamEnd(int32_t waitCount);
624
625
626            // caller must hold lock on mLock for all _l methods
627
628            status_t createTrack_l(audio_stream_type_t streamType,
629                                 uint32_t sampleRate,
630                                 audio_format_t format,
631                                 size_t frameCount,
632                                 audio_output_flags_t flags,
633                                 const sp<IMemory>& sharedBuffer,
634                                 audio_io_handle_t output,
635                                 size_t epoch);
636
637            // can only be called when mState != STATE_ACTIVE
638            void flush_l();
639
640            void setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);
641            audio_io_handle_t getOutput_l();
642
643            // FIXME enum is faster than strcmp() for parameter 'from'
644            status_t restoreTrack_l(const char *from);
645
646            bool     isOffloaded() const
647                { return (mFlags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) != 0; }
648
649    // may be changed if IAudioTrack is re-created
650    sp<IAudioTrack>         mAudioTrack;
651    sp<IMemory>             mCblkMemory;
652    audio_track_cblk_t*     mCblk;                  // re-load after mLock.unlock()
653
654    sp<AudioTrackThread>    mAudioTrackThread;
655    float                   mVolume[2];
656    float                   mSendLevel;
657    uint32_t                mSampleRate;
658    size_t                  mFrameCount;            // corresponds to current IAudioTrack
659    size_t                  mReqFrameCount;         // frame count to request the next time a new
660                                                    // IAudioTrack is needed
661
662    // constant after constructor or set()
663    audio_format_t          mFormat;                // as requested by client, not forced to 16-bit
664    audio_stream_type_t     mStreamType;
665    uint32_t                mChannelCount;
666    audio_channel_mask_t    mChannelMask;
667    transfer_type           mTransfer;
668
669    // mFrameSize is equal to mFrameSizeAF for non-PCM or 16-bit PCM data.  For 8-bit PCM data, it's
670    // twice as large as mFrameSize because data is expanded to 16-bit before it's stored in buffer.
671    size_t                  mFrameSize;             // app-level frame size
672    size_t                  mFrameSizeAF;           // AudioFlinger frame size
673
674    status_t                mStatus;
675
676    // can change dynamically when IAudioTrack invalidated
677    uint32_t                mLatency;               // in ms
678
679    // Indicates the current track state.  Protected by mLock.
680    enum State {
681        STATE_ACTIVE,
682        STATE_STOPPED,
683        STATE_PAUSED,
684        STATE_PAUSED_STOPPING,
685        STATE_FLUSHED,
686        STATE_STOPPING,
687    }                       mState;
688
689    // for client callback handler
690    callback_t              mCbf;                   // callback handler for events, or NULL
691    void*                   mUserData;
692
693    // for notification APIs
694    uint32_t                mNotificationFramesReq; // requested number of frames between each
695                                                    // notification callback,
696                                                    // at initial source sample rate
697    uint32_t                mNotificationFramesAct; // actual number of frames between each
698                                                    // notification callback,
699                                                    // at initial source sample rate
700    bool                    mRefreshRemaining;      // processAudioBuffer() should refresh
701                                                    // mRemainingFrames and mRetryOnPartialBuffer
702
703    // These are private to processAudioBuffer(), and are not protected by a lock
704    uint32_t                mRemainingFrames;       // number of frames to request in obtainBuffer()
705    bool                    mRetryOnPartialBuffer;  // sleep and retry after partial obtainBuffer()
706    uint32_t                mObservedSequence;      // last observed value of mSequence
707
708    sp<IMemory>             mSharedBuffer;
709    uint32_t                mLoopPeriod;            // in frames, zero means looping is disabled
710    uint32_t                mMarkerPosition;        // in wrapping (overflow) frame units
711    bool                    mMarkerReached;
712    uint32_t                mNewPosition;           // in frames
713    uint32_t                mUpdatePeriod;          // in frames, zero means no EVENT_NEW_POS
714
715    audio_output_flags_t    mFlags;
716    int                     mSessionId;
717    int                     mAuxEffectId;
718
719    mutable Mutex           mLock;
720
721    bool                    mIsTimed;
722    int                     mPreviousPriority;          // before start()
723    SchedPolicy             mPreviousSchedulingGroup;
724    bool                    mAwaitBoost;    // thread should wait for priority boost before running
725
726    // The proxy should only be referenced while a lock is held because the proxy isn't
727    // multi-thread safe, especially the SingleStateQueue part of the proxy.
728    // An exception is that a blocking ClientProxy::obtainBuffer() may be called without a lock,
729    // provided that the caller also holds an extra reference to the proxy and shared memory to keep
730    // them around in case they are replaced during the obtainBuffer().
731    sp<StaticAudioTrackClientProxy> mStaticProxy;   // for type safety only
732    sp<AudioTrackClientProxy>       mProxy;         // primary owner of the memory
733
734    bool                    mInUnderrun;            // whether track is currently in underrun state
735    String8                 mName;                  // server's name for this IAudioTrack
736
737private:
738    class DeathNotifier : public IBinder::DeathRecipient {
739    public:
740        DeathNotifier(AudioTrack* audioTrack) : mAudioTrack(audioTrack) { }
741    protected:
742        virtual void        binderDied(const wp<IBinder>& who);
743    private:
744        const wp<AudioTrack> mAudioTrack;
745    };
746
747    sp<DeathNotifier>       mDeathNotifier;
748    uint32_t                mSequence;              // incremented for each new IAudioTrack attempt
749    audio_io_handle_t       mOutput;                // cached output io handle
750};
751
752class TimedAudioTrack : public AudioTrack
753{
754public:
755    TimedAudioTrack();
756
757    /* allocate a shared memory buffer that can be passed to queueTimedBuffer */
758    status_t allocateTimedBuffer(size_t size, sp<IMemory>* buffer);
759
760    /* queue a buffer obtained via allocateTimedBuffer for playback at the
761       given timestamp.  PTS units are microseconds on the media time timeline.
762       The media time transform (set with setMediaTimeTransform) set by the
763       audio producer will handle converting from media time to local time
764       (perhaps going through the common time timeline in the case of
765       synchronized multiroom audio case) */
766    status_t queueTimedBuffer(const sp<IMemory>& buffer, int64_t pts);
767
768    /* define a transform between media time and either common time or
769       local time */
770    enum TargetTimeline {LOCAL_TIME, COMMON_TIME};
771    status_t setMediaTimeTransform(const LinearTransform& xform,
772                                   TargetTimeline target);
773};
774
775}; // namespace android
776
777#endif // ANDROID_AUDIOTRACK_H
778