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 <media/AudioResamplerPublic.h>
25 #include <media/MediaMetricsItem.h>
26 #include <media/Modulo.h>
27 #include <utils/threads.h>
28 
29 #include "android/media/BnAudioTrackCallback.h"
30 #include "android/media/IAudioTrackCallback.h"
31 
32 namespace android {
33 
34 // ----------------------------------------------------------------------------
35 
36 struct audio_track_cblk_t;
37 class AudioTrackClientProxy;
38 class StaticAudioTrackClientProxy;
39 
40 // ----------------------------------------------------------------------------
41 
42 class AudioTrack : public AudioSystem::AudioDeviceCallback
43 {
44 public:
45 
46     /* Events used by AudioTrack callback function (callback_t).
47      * Keep in sync with frameworks/base/media/java/android/media/AudioTrack.java NATIVE_EVENT_*.
48      */
49     enum event_type {
50         EVENT_MORE_DATA = 0,        // Request to write more data to buffer.
51                                     // This event only occurs for TRANSFER_CALLBACK.
52                                     // If this event is delivered but the callback handler
53                                     // does not want to write more data, the handler must
54                                     // ignore the event by setting frameCount to zero.
55                                     // This might occur, for example, if the application is
56                                     // waiting for source data or is at the end of stream.
57                                     //
58                                     // For data filling, it is preferred that the callback
59                                     // does not block and instead returns a short count on
60                                     // the amount of data actually delivered
61                                     // (or 0, if no data is currently available).
62         EVENT_UNDERRUN = 1,         // Buffer underrun occurred. This will not occur for
63                                     // static tracks.
64         EVENT_LOOP_END = 2,         // Sample loop end was reached; playback restarted from
65                                     // loop start if loop count was not 0 for a static track.
66         EVENT_MARKER = 3,           // Playback head is at the specified marker position
67                                     // (See setMarkerPosition()).
68         EVENT_NEW_POS = 4,          // Playback head is at a new position
69                                     // (See setPositionUpdatePeriod()).
70         EVENT_BUFFER_END = 5,       // Playback has completed for a static track.
71         EVENT_NEW_IAUDIOTRACK = 6,  // IAudioTrack was re-created, either due to re-routing and
72                                     // voluntary invalidation by mediaserver, or mediaserver crash.
73         EVENT_STREAM_END = 7,       // Sent after all the buffers queued in AF and HW are played
74                                     // back (after stop is called) for an offloaded track.
75 #if 0   // FIXME not yet implemented
76         EVENT_NEW_TIMESTAMP = 8,    // Delivered periodically and when there's a significant change
77                                     // in the mapping from frame position to presentation time.
78                                     // See AudioTimestamp for the information included with event.
79 #endif
80         EVENT_CAN_WRITE_MORE_DATA = 9,// Notification that more data can be given by write()
81                                     // This event only occurs for TRANSFER_SYNC_NOTIF_CALLBACK.
82     };
83 
84     /* Client should declare a Buffer and pass the address to obtainBuffer()
85      * and releaseBuffer().  See also callback_t for EVENT_MORE_DATA.
86      */
87 
88     class Buffer
89     {
90     public:
91         // FIXME use m prefix
92         size_t      frameCount;   // number of sample frames corresponding to size;
93                                   // on input to obtainBuffer() it is the number of frames desired,
94                                   // on output from obtainBuffer() it is the number of available
95                                   //    [empty slots for] frames to be filled
96                                   // on input to releaseBuffer() it is currently ignored
97 
98         size_t      size;         // input/output in bytes == frameCount * frameSize
99                                   // on input to obtainBuffer() it is ignored
100                                   // on output from obtainBuffer() it is the number of available
101                                   //    [empty slots for] bytes to be filled,
102                                   //    which is frameCount * frameSize
103                                   // on input to releaseBuffer() it is the number of bytes to
104                                   //    release
105                                   // FIXME This is redundant with respect to frameCount.  Consider
106                                   //    removing size and making frameCount the primary field.
107 
108         union {
109             void*       raw;
110             int16_t*    i16;      // signed 16-bit
111             int8_t*     i8;       // unsigned 8-bit, offset by 0x80
112         };                        // input to obtainBuffer(): unused, output: pointer to buffer
113 
114         uint32_t    sequence;       // IAudioTrack instance sequence number, as of obtainBuffer().
115                                     // It is set by obtainBuffer() and confirmed by releaseBuffer().
116                                     // Not "user-serviceable".
117                                     // TODO Consider sp<IMemory> instead, or in addition to this.
118     };
119 
120     /* As a convenience, if a callback is supplied, a handler thread
121      * is automatically created with the appropriate priority. This thread
122      * invokes the callback when a new buffer becomes available or various conditions occur.
123      * Parameters:
124      *
125      * event:   type of event notified (see enum AudioTrack::event_type).
126      * user:    Pointer to context for use by the callback receiver.
127      * info:    Pointer to optional parameter according to event type:
128      *          - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write
129      *            more bytes than indicated by 'size' field and update 'size' if fewer bytes are
130      *            written.
131      *          - EVENT_UNDERRUN: unused.
132      *          - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining.
133      *          - EVENT_MARKER: pointer to const uint32_t containing the marker position in frames.
134      *          - EVENT_NEW_POS: pointer to const uint32_t containing the new position in frames.
135      *          - EVENT_BUFFER_END: unused.
136      *          - EVENT_NEW_IAUDIOTRACK: unused.
137      *          - EVENT_STREAM_END: unused.
138      *          - EVENT_NEW_TIMESTAMP: pointer to const AudioTimestamp.
139      */
140 
141     typedef void (*callback_t)(int event, void* user, void *info);
142 
143     /* Returns the minimum frame count required for the successful creation of
144      * an AudioTrack object.
145      * Returned status (from utils/Errors.h) can be:
146      *  - NO_ERROR: successful operation
147      *  - NO_INIT: audio server or audio hardware not initialized
148      *  - BAD_VALUE: unsupported configuration
149      * frameCount is guaranteed to be non-zero if status is NO_ERROR,
150      * and is undefined otherwise.
151      * FIXME This API assumes a route, and so should be deprecated.
152      */
153 
154     static status_t getMinFrameCount(size_t* frameCount,
155                                      audio_stream_type_t streamType,
156                                      uint32_t sampleRate);
157 
158     /* Check if direct playback is possible for the given audio configuration and attributes.
159      * Return true if output is possible for the given parameters. Otherwise returns false.
160      */
161     static bool isDirectOutputSupported(const audio_config_base_t& config,
162                                         const audio_attributes_t& attributes);
163 
164     /* How data is transferred to AudioTrack
165      */
166     enum transfer_type {
167         TRANSFER_DEFAULT,   // not specified explicitly; determine from the other parameters
168         TRANSFER_CALLBACK,  // callback EVENT_MORE_DATA
169         TRANSFER_OBTAIN,    // call obtainBuffer() and releaseBuffer()
170         TRANSFER_SYNC,      // synchronous write()
171         TRANSFER_SHARED,    // shared memory
172         TRANSFER_SYNC_NOTIF_CALLBACK, // synchronous write(), notif EVENT_CAN_WRITE_MORE_DATA
173     };
174 
175     /* Constructs an uninitialized AudioTrack. No connection with
176      * AudioFlinger takes place.  Use set() after this.
177      */
178                         AudioTrack();
179 
180     /* Creates an AudioTrack object and registers it with AudioFlinger.
181      * Once created, the track needs to be started before it can be used.
182      * Unspecified values are set to appropriate default values.
183      *
184      * Parameters:
185      *
186      * streamType:         Select the type of audio stream this track is attached to
187      *                     (e.g. AUDIO_STREAM_MUSIC).
188      * sampleRate:         Data source sampling rate in Hz.  Zero means to use the sink sample rate.
189      *                     A non-zero value must be specified if AUDIO_OUTPUT_FLAG_DIRECT is set.
190      *                     0 will not work with current policy implementation for direct output
191      *                     selection where an exact match is needed for sampling rate.
192      * format:             Audio format. For mixed tracks, any PCM format supported by server is OK.
193      *                     For direct and offloaded tracks, the possible format(s) depends on the
194      *                     output sink.
195      * channelMask:        Channel mask, such that audio_is_output_channel(channelMask) is true.
196      * frameCount:         Minimum size of track PCM buffer in frames. This defines the
197      *                     application's contribution to the
198      *                     latency of the track. The actual size selected by the AudioTrack could be
199      *                     larger if the requested size is not compatible with current audio HAL
200      *                     configuration.  Zero means to use a default value.
201      * flags:              See comments on audio_output_flags_t in <system/audio.h>.
202      * cbf:                Callback function. If not null, this function is called periodically
203      *                     to provide new data in TRANSFER_CALLBACK mode
204      *                     and inform of marker, position updates, etc.
205      * user:               Context for use by the callback receiver.
206      * notificationFrames: The callback function is called each time notificationFrames PCM
207      *                     frames have been consumed from track input buffer by server.
208      *                     Zero means to use a default value, which is typically:
209      *                      - fast tracks: HAL buffer size, even if track frameCount is larger
210      *                      - normal tracks: 1/2 of track frameCount
211      *                     A positive value means that many frames at initial source sample rate.
212      *                     A negative value for this parameter specifies the negative of the
213      *                     requested number of notifications (sub-buffers) in the entire buffer.
214      *                     For fast tracks, the FastMixer will process one sub-buffer at a time.
215      *                     The size of each sub-buffer is determined by the HAL.
216      *                     To get "double buffering", for example, one should pass -2.
217      *                     The minimum number of sub-buffers is 1 (expressed as -1),
218      *                     and the maximum number of sub-buffers is 8 (expressed as -8).
219      *                     Negative is only permitted for fast tracks, and if frameCount is zero.
220      *                     TODO It is ugly to overload a parameter in this way depending on
221      *                     whether it is positive, negative, or zero.  Consider splitting apart.
222      * sessionId:          Specific session ID, or zero to use default.
223      * transferType:       How data is transferred to AudioTrack.
224      * offloadInfo:        If not NULL, provides offload parameters for
225      *                     AudioSystem::getOutputForAttr().
226      * uid:                User ID of the app which initially requested this AudioTrack
227      *                     for power management tracking, or -1 for current user ID.
228      * pid:                Process ID of the app which initially requested this AudioTrack
229      *                     for power management tracking, or -1 for current process ID.
230      * pAttributes:        If not NULL, supersedes streamType for use case selection.
231      * doNotReconnect:     If set to true, AudioTrack won't automatically recreate the IAudioTrack
232                            binder to AudioFlinger.
233                            It will return an error instead.  The application will recreate
234                            the track based on offloading or different channel configuration, etc.
235      * maxRequiredSpeed:   For PCM tracks, this creates an appropriate buffer size that will allow
236      *                     maxRequiredSpeed playback. Values less than 1.0f and greater than
237      *                     AUDIO_TIMESTRETCH_SPEED_MAX will be clamped.  For non-PCM tracks
238      *                     and direct or offloaded tracks, this parameter is ignored.
239      * selectedDeviceId:   Selected device id of the app which initially requested the AudioTrack
240      *                     to open with a specific device.
241      * threadCanCallJava:  Not present in parameter list, and so is fixed at false.
242      */
243 
244                         AudioTrack( audio_stream_type_t streamType,
245                                     uint32_t sampleRate,
246                                     audio_format_t format,
247                                     audio_channel_mask_t channelMask,
248                                     size_t frameCount    = 0,
249                                     audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
250                                     callback_t cbf       = NULL,
251                                     void* user           = NULL,
252                                     int32_t notificationFrames = 0,
253                                     audio_session_t sessionId  = AUDIO_SESSION_ALLOCATE,
254                                     transfer_type transferType = TRANSFER_DEFAULT,
255                                     const audio_offload_info_t *offloadInfo = NULL,
256                                     uid_t uid = AUDIO_UID_INVALID,
257                                     pid_t pid = -1,
258                                     const audio_attributes_t* pAttributes = NULL,
259                                     bool doNotReconnect = false,
260                                     float maxRequiredSpeed = 1.0f,
261                                     audio_port_handle_t selectedDeviceId = AUDIO_PORT_HANDLE_NONE);
262 
263     /* Creates an audio track and registers it with AudioFlinger.
264      * With this constructor, the track is configured for static buffer mode.
265      * Data to be rendered is passed in a shared memory buffer
266      * identified by the argument sharedBuffer, which should be non-0.
267      * If sharedBuffer is zero, this constructor is equivalent to the previous constructor
268      * but without the ability to specify a non-zero value for the frameCount parameter.
269      * The memory should be initialized to the desired data before calling start().
270      * The write() method is not supported in this case.
271      * It is recommended to pass a callback function to be notified of playback end by an
272      * EVENT_UNDERRUN event.
273      */
274 
275                         AudioTrack( audio_stream_type_t streamType,
276                                     uint32_t sampleRate,
277                                     audio_format_t format,
278                                     audio_channel_mask_t channelMask,
279                                     const sp<IMemory>& sharedBuffer,
280                                     audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
281                                     callback_t cbf      = NULL,
282                                     void* user          = NULL,
283                                     int32_t notificationFrames = 0,
284                                     audio_session_t sessionId   = AUDIO_SESSION_ALLOCATE,
285                                     transfer_type transferType = TRANSFER_DEFAULT,
286                                     const audio_offload_info_t *offloadInfo = NULL,
287                                     uid_t uid = AUDIO_UID_INVALID,
288                                     pid_t pid = -1,
289                                     const audio_attributes_t* pAttributes = NULL,
290                                     bool doNotReconnect = false,
291                                     float maxRequiredSpeed = 1.0f);
292 
293     /* Terminates the AudioTrack and unregisters it from AudioFlinger.
294      * Also destroys all resources associated with the AudioTrack.
295      */
296 protected:
297                         virtual ~AudioTrack();
298 public:
299 
300     /* Initialize an AudioTrack that was created using the AudioTrack() constructor.
301      * Don't call set() more than once, or after the AudioTrack() constructors that take parameters.
302      * set() is not multi-thread safe.
303      * Returned status (from utils/Errors.h) can be:
304      *  - NO_ERROR: successful initialization
305      *  - INVALID_OPERATION: AudioTrack is already initialized
306      *  - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...)
307      *  - NO_INIT: audio server or audio hardware not initialized
308      * If status is not equal to NO_ERROR, don't call any other APIs on this AudioTrack.
309      * If sharedBuffer is non-0, the frameCount parameter is ignored and
310      * replaced by the shared buffer's total allocated size in frame units.
311      *
312      * Parameters not listed in the AudioTrack constructors above:
313      *
314      * threadCanCallJava:  Whether callbacks are made from an attached thread and thus can call JNI.
315      *      Only set to true when AudioTrack object is used for a java android.media.AudioTrack
316      *      in its JNI code.
317      *
318      * Internal state post condition:
319      *      (mStreamType == AUDIO_STREAM_DEFAULT) implies this AudioTrack has valid attributes
320      */
321             status_t    set(audio_stream_type_t streamType,
322                             uint32_t sampleRate,
323                             audio_format_t format,
324                             audio_channel_mask_t channelMask,
325                             size_t frameCount   = 0,
326                             audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE,
327                             callback_t cbf      = NULL,
328                             void* user          = NULL,
329                             int32_t notificationFrames = 0,
330                             const sp<IMemory>& sharedBuffer = 0,
331                             bool threadCanCallJava = false,
332                             audio_session_t sessionId  = AUDIO_SESSION_ALLOCATE,
333                             transfer_type transferType = TRANSFER_DEFAULT,
334                             const audio_offload_info_t *offloadInfo = NULL,
335                             uid_t uid = AUDIO_UID_INVALID,
336                             pid_t pid = -1,
337                             const audio_attributes_t* pAttributes = NULL,
338                             bool doNotReconnect = false,
339                             float maxRequiredSpeed = 1.0f,
340                             audio_port_handle_t selectedDeviceId = AUDIO_PORT_HANDLE_NONE);
341 
342     /* Result of constructing the AudioTrack. This must be checked for successful initialization
343      * before using any AudioTrack API (except for set()), because using
344      * an uninitialized AudioTrack produces undefined results.
345      * See set() method above for possible return codes.
346      */
initCheck()347             status_t    initCheck() const   { return mStatus; }
348 
349     /* Returns this track's estimated latency in milliseconds.
350      * This includes the latency due to AudioTrack buffer size, AudioMixer (if any)
351      * and audio hardware driver.
352      */
353             uint32_t    latency();
354 
355     /* Returns the number of application-level buffer underruns
356      * since the AudioTrack was created.
357      */
358             uint32_t    getUnderrunCount() const;
359 
360     /* getters, see constructors and set() */
361 
362             audio_stream_type_t streamType() const;
format()363             audio_format_t format() const   { return mFormat; }
364 
365     /* Return frame size in bytes, which for linear PCM is
366      * channelCount * (bit depth per channel / 8).
367      * channelCount is determined from channelMask, and bit depth comes from format.
368      * For non-linear formats, the frame size is typically 1 byte.
369      */
frameSize()370             size_t      frameSize() const   { return mFrameSize; }
371 
channelCount()372             uint32_t    channelCount() const { return mChannelCount; }
frameCount()373             size_t      frameCount() const  { return mFrameCount; }
374 
375     /*
376      * Return the period of the notification callback in frames.
377      * This value is set when the AudioTrack is constructed.
378      * It can be modified if the AudioTrack is rerouted.
379      */
getNotificationPeriodInFrames()380             uint32_t    getNotificationPeriodInFrames() const { return mNotificationFramesAct; }
381 
382     /* Return effective size of audio buffer that an application writes to
383      * or a negative error if the track is uninitialized.
384      */
385             ssize_t     getBufferSizeInFrames();
386 
387     /* Returns the buffer duration in microseconds at current playback rate.
388      */
389             status_t    getBufferDurationInUs(int64_t *duration);
390 
391     /* Set the effective size of audio buffer that an application writes to.
392      * This is used to determine the amount of available room in the buffer,
393      * which determines when a write will block.
394      * This allows an application to raise and lower the audio latency.
395      * The requested size may be adjusted so that it is
396      * greater or equal to the absolute minimum and
397      * less than or equal to the getBufferCapacityInFrames().
398      * It may also be adjusted slightly for internal reasons.
399      *
400      * Return the final size or a negative error if the track is unitialized
401      * or does not support variable sizes.
402      */
403             ssize_t     setBufferSizeInFrames(size_t size);
404 
405     /* Return the static buffer specified in constructor or set(), or 0 for streaming mode */
sharedBuffer()406             sp<IMemory> sharedBuffer() const { return mSharedBuffer; }
407 
408     /*
409      * return metrics information for the current track.
410      */
411             status_t getMetrics(mediametrics::Item * &item);
412 
413     /*
414      * Set name of API that is using this object.
415      * For example "aaudio" or "opensles".
416      * This may be logged or reported as part of MediaMetrics.
417      */
setCallerName(const std::string & name)418             void setCallerName(const std::string &name) {
419                 mCallerName = name;
420             }
421 
getCallerName()422             std::string getCallerName() const {
423                 return mCallerName;
424             };
425 
426     /* After it's created the track is not active. Call start() to
427      * make it active. If set, the callback will start being called.
428      * If the track was previously paused, volume is ramped up over the first mix buffer.
429      */
430             status_t        start();
431 
432     /* Stop a track.
433      * In static buffer mode, the track is stopped immediately.
434      * In streaming mode, the callback will cease being called.  Note that obtainBuffer() still
435      * works and will fill up buffers until the pool is exhausted, and then will return WOULD_BLOCK.
436      * In streaming mode the stop does not occur immediately: any data remaining in the buffer
437      * is first drained, mixed, and output, and only then is the track marked as stopped.
438      */
439             void        stop();
440             bool        stopped() const;
441 
442     /* Flush a stopped or paused track. All previously buffered data is discarded immediately.
443      * This has the effect of draining the buffers without mixing or output.
444      * Flush is intended for streaming mode, for example before switching to non-contiguous content.
445      * This function is a no-op if the track is not stopped or paused, or uses a static buffer.
446      */
447             void        flush();
448 
449     /* Pause a track. After pause, the callback will cease being called and
450      * obtainBuffer returns WOULD_BLOCK. Note that obtainBuffer() still works
451      * and will fill up buffers until the pool is exhausted.
452      * Volume is ramped down over the next mix buffer following the pause request,
453      * and then the track is marked as paused.  It can be resumed with ramp up by start().
454      */
455             void        pause();
456 
457     /* Set volume for this track, mostly used for games' sound effects
458      * left and right volumes. Levels must be >= 0.0 and <= 1.0.
459      * This is the older API.  New applications should use setVolume(float) when possible.
460      */
461             status_t    setVolume(float left, float right);
462 
463     /* Set volume for all channels.  This is the preferred API for new applications,
464      * especially for multi-channel content.
465      */
466             status_t    setVolume(float volume);
467 
468     /* Set the send level for this track. An auxiliary effect should be attached
469      * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0.
470      */
471             status_t    setAuxEffectSendLevel(float level);
472             void        getAuxEffectSendLevel(float* level) const;
473 
474     /* Set source sample rate for this track in Hz, mostly used for games' sound effects.
475      * Zero is not permitted.
476      */
477             status_t    setSampleRate(uint32_t sampleRate);
478 
479     /* Return current source sample rate in Hz.
480      * If specified as zero in constructor or set(), this will be the sink sample rate.
481      */
482             uint32_t    getSampleRate() const;
483 
484     /* Return the original source sample rate in Hz. This corresponds to the sample rate
485      * if playback rate had normal speed and pitch.
486      */
487             uint32_t    getOriginalSampleRate() const;
488 
489     /* Set source playback rate for timestretch
490      * 1.0 is normal speed: < 1.0 is slower, > 1.0 is faster
491      * 1.0 is normal pitch: < 1.0 is lower pitch, > 1.0 is higher pitch
492      *
493      * AUDIO_TIMESTRETCH_SPEED_MIN <= speed <= AUDIO_TIMESTRETCH_SPEED_MAX
494      * AUDIO_TIMESTRETCH_PITCH_MIN <= pitch <= AUDIO_TIMESTRETCH_PITCH_MAX
495      *
496      * Speed increases the playback rate of media, but does not alter pitch.
497      * Pitch increases the "tonal frequency" of media, but does not affect the playback rate.
498      */
499             status_t    setPlaybackRate(const AudioPlaybackRate &playbackRate);
500 
501     /* Return current playback rate */
502             const AudioPlaybackRate& getPlaybackRate() const;
503 
504     /* Enables looping and sets the start and end points of looping.
505      * Only supported for static buffer mode.
506      *
507      * Parameters:
508      *
509      * loopStart:   loop start in frames relative to start of buffer.
510      * loopEnd:     loop end in frames relative to start of buffer.
511      * loopCount:   number of loops to execute. Calling setLoop() with loopCount == 0 cancels any
512      *              pending or active loop. loopCount == -1 means infinite looping.
513      *
514      * For proper operation the following condition must be respected:
515      *      loopCount != 0 implies 0 <= loopStart < loopEnd <= frameCount().
516      *
517      * If the loop period (loopEnd - loopStart) is too small for the implementation to support,
518      * setLoop() will return BAD_VALUE.  loopCount must be >= -1.
519      *
520      */
521             status_t    setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount);
522 
523     /* Sets marker position. When playback reaches the number of frames specified, a callback with
524      * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker
525      * notification callback.  To set a marker at a position which would compute as 0,
526      * a workaround is to set the marker at a nearby position such as ~0 or 1.
527      * If the AudioTrack has been opened with no callback function associated, the operation will
528      * fail.
529      *
530      * Parameters:
531      *
532      * marker:   marker position expressed in wrapping (overflow) frame units,
533      *           like the return value of getPosition().
534      *
535      * Returned status (from utils/Errors.h) can be:
536      *  - NO_ERROR: successful operation
537      *  - INVALID_OPERATION: the AudioTrack has no callback installed.
538      */
539             status_t    setMarkerPosition(uint32_t marker);
540             status_t    getMarkerPosition(uint32_t *marker) const;
541 
542     /* Sets position update period. Every time the number of frames specified has been played,
543      * a callback with event type EVENT_NEW_POS is called.
544      * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification
545      * callback.
546      * If the AudioTrack has been opened with no callback function associated, the operation will
547      * fail.
548      * Extremely small values may be rounded up to a value the implementation can support.
549      *
550      * Parameters:
551      *
552      * updatePeriod:  position update notification period expressed in frames.
553      *
554      * Returned status (from utils/Errors.h) can be:
555      *  - NO_ERROR: successful operation
556      *  - INVALID_OPERATION: the AudioTrack has no callback installed.
557      */
558             status_t    setPositionUpdatePeriod(uint32_t updatePeriod);
559             status_t    getPositionUpdatePeriod(uint32_t *updatePeriod) const;
560 
561     /* Sets playback head position.
562      * Only supported for static buffer mode.
563      *
564      * Parameters:
565      *
566      * position:  New playback head position in frames relative to start of buffer.
567      *            0 <= position <= frameCount().  Note that end of buffer is permitted,
568      *            but will result in an immediate underrun if started.
569      *
570      * Returned status (from utils/Errors.h) can be:
571      *  - NO_ERROR: successful operation
572      *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
573      *  - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack
574      *               buffer
575      */
576             status_t    setPosition(uint32_t position);
577 
578     /* Return the total number of frames played since playback start.
579      * The counter will wrap (overflow) periodically, e.g. every ~27 hours at 44.1 kHz.
580      * It is reset to zero by flush(), reload(), and stop().
581      *
582      * Parameters:
583      *
584      *  position:  Address where to return play head position.
585      *
586      * Returned status (from utils/Errors.h) can be:
587      *  - NO_ERROR: successful operation
588      *  - BAD_VALUE:  position is NULL
589      */
590             status_t    getPosition(uint32_t *position);
591 
592     /* For static buffer mode only, this returns the current playback position in frames
593      * relative to start of buffer.  It is analogous to the position units used by
594      * setLoop() and setPosition().  After underrun, the position will be at end of buffer.
595      */
596             status_t    getBufferPosition(uint32_t *position);
597 
598     /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids
599      * rewriting the buffer before restarting playback after a stop.
600      * This method must be called with the AudioTrack in paused or stopped state.
601      * Not allowed in streaming mode.
602      *
603      * Returned status (from utils/Errors.h) can be:
604      *  - NO_ERROR: successful operation
605      *  - INVALID_OPERATION: the AudioTrack is not stopped or paused, or is streaming mode.
606      */
607             status_t    reload();
608 
609     /**
610      * @param transferType
611      * @return text string that matches the enum name
612      */
613             static const char * convertTransferToText(transfer_type transferType);
614 
615     /* Returns a handle on the audio output used by this AudioTrack.
616      *
617      * Parameters:
618      *  none.
619      *
620      * Returned value:
621      *  handle on audio hardware output, or AUDIO_IO_HANDLE_NONE if the
622      *  track needed to be re-created but that failed
623      */
624 private:
625             audio_io_handle_t    getOutput() const;
626 public:
627 
628     /* Selects the audio device to use for output of this AudioTrack. A value of
629      * AUDIO_PORT_HANDLE_NONE indicates default (AudioPolicyManager) routing.
630      *
631      * Parameters:
632      *  The device ID of the selected device (as returned by the AudioDevicesManager API).
633      *
634      * Returned value:
635      *  - NO_ERROR: successful operation
636      *    TODO: what else can happen here?
637      */
638             status_t    setOutputDevice(audio_port_handle_t deviceId);
639 
640     /* Returns the ID of the audio device selected for this AudioTrack.
641      * A value of AUDIO_PORT_HANDLE_NONE indicates default (AudioPolicyManager) routing.
642      *
643      * Parameters:
644      *  none.
645      */
646      audio_port_handle_t getOutputDevice();
647 
648      /* Returns the ID of the audio device actually used by the output to which this AudioTrack is
649       * attached.
650       * When the AudioTrack is inactive, the device ID returned can be either:
651       * - AUDIO_PORT_HANDLE_NONE if the AudioTrack is not attached to any output.
652       * - The device ID used before paused or stopped.
653       * - The device ID selected by audio policy manager of setOutputDevice() if the AudioTrack
654       * has not been started yet.
655       *
656       * Parameters:
657       *  none.
658       */
659      audio_port_handle_t getRoutedDeviceId();
660 
661     /* Returns the unique session ID associated with this track.
662      *
663      * Parameters:
664      *  none.
665      *
666      * Returned value:
667      *  AudioTrack session ID.
668      */
getSessionId()669             audio_session_t getSessionId() const { return mSessionId; }
670 
671     /* Attach track auxiliary output to specified effect. Use effectId = 0
672      * to detach track from effect.
673      *
674      * Parameters:
675      *
676      * effectId:  effectId obtained from AudioEffect::id().
677      *
678      * Returned status (from utils/Errors.h) can be:
679      *  - NO_ERROR: successful operation
680      *  - INVALID_OPERATION: the effect is not an auxiliary effect.
681      *  - BAD_VALUE: The specified effect ID is invalid
682      */
683             status_t    attachAuxEffect(int effectId);
684 
685     /* Public API for TRANSFER_OBTAIN mode.
686      * Obtains a buffer of up to "audioBuffer->frameCount" empty slots for frames.
687      * After filling these slots with data, the caller should release them with releaseBuffer().
688      * If the track buffer is not full, obtainBuffer() returns as many contiguous
689      * [empty slots for] frames as are available immediately.
690      *
691      * If nonContig is non-NULL, it is an output parameter that will be set to the number of
692      * additional non-contiguous frames that are predicted to be available immediately,
693      * if the client were to release the first frames and then call obtainBuffer() again.
694      * This value is only a prediction, and needs to be confirmed.
695      * It will be set to zero for an error return.
696      *
697      * If the track buffer is full and track is stopped, obtainBuffer() returns WOULD_BLOCK
698      * regardless of the value of waitCount.
699      * If the track buffer is full and track is not stopped, obtainBuffer() blocks with a
700      * maximum timeout based on waitCount; see chart below.
701      * Buffers will be returned until the pool
702      * is exhausted, at which point obtainBuffer() will either block
703      * or return WOULD_BLOCK depending on the value of the "waitCount"
704      * parameter.
705      *
706      * Interpretation of waitCount:
707      *  +n  limits wait time to n * WAIT_PERIOD_MS,
708      *  -1  causes an (almost) infinite wait time,
709      *   0  non-blocking.
710      *
711      * Buffer fields
712      * On entry:
713      *  frameCount  number of [empty slots for] frames requested
714      *  size        ignored
715      *  raw         ignored
716      *  sequence    ignored
717      * After error return:
718      *  frameCount  0
719      *  size        0
720      *  raw         undefined
721      *  sequence    undefined
722      * After successful return:
723      *  frameCount  actual number of [empty slots for] frames available, <= number requested
724      *  size        actual number of bytes available
725      *  raw         pointer to the buffer
726      *  sequence    IAudioTrack instance sequence number, as of obtainBuffer()
727      */
728             status_t    obtainBuffer(Buffer* audioBuffer, int32_t waitCount,
729                                 size_t *nonContig = NULL);
730 
731 private:
732     /* If nonContig is non-NULL, it is an output parameter that will be set to the number of
733      * additional non-contiguous frames that are predicted to be available immediately,
734      * if the client were to release the first frames and then call obtainBuffer() again.
735      * This value is only a prediction, and needs to be confirmed.
736      * It will be set to zero for an error return.
737      * FIXME We could pass an array of Buffers instead of only one Buffer to obtainBuffer(),
738      * in case the requested amount of frames is in two or more non-contiguous regions.
739      * FIXME requested and elapsed are both relative times.  Consider changing to absolute time.
740      */
741             status_t    obtainBuffer(Buffer* audioBuffer, const struct timespec *requested,
742                                      struct timespec *elapsed = NULL, size_t *nonContig = NULL);
743 public:
744 
745     /* Public API for TRANSFER_OBTAIN mode.
746      * Release a filled buffer of frames for AudioFlinger to process.
747      *
748      * Buffer fields:
749      *  frameCount  currently ignored but recommend to set to actual number of frames filled
750      *  size        actual number of bytes filled, must be multiple of frameSize
751      *  raw         ignored
752      */
753             void        releaseBuffer(const Buffer* audioBuffer);
754 
755     /* As a convenience we provide a write() interface to the audio buffer.
756      * Input parameter 'size' is in byte units.
757      * This is implemented on top of obtainBuffer/releaseBuffer. For best
758      * performance use callbacks. Returns actual number of bytes written >= 0,
759      * or one of the following negative status codes:
760      *      INVALID_OPERATION   AudioTrack is configured for static buffer or streaming mode
761      *      BAD_VALUE           size is invalid
762      *      WOULD_BLOCK         when obtainBuffer() returns same, or
763      *                          AudioTrack was stopped during the write
764      *      DEAD_OBJECT         when AudioFlinger dies or the output device changes and
765      *                          the track cannot be automatically restored.
766      *                          The application needs to recreate the AudioTrack
767      *                          because the audio device changed or AudioFlinger died.
768      *                          This typically occurs for direct or offload tracks
769      *                          or if mDoNotReconnect is true.
770      *      or any other error code returned by IAudioTrack::start() or restoreTrack_l().
771      * Default behavior is to only return when all data has been transferred. Set 'blocking' to
772      * false for the method to return immediately without waiting to try multiple times to write
773      * the full content of the buffer.
774      */
775             ssize_t     write(const void* buffer, size_t size, bool blocking = true);
776 
777     /*
778      * Dumps the state of an audio track.
779      * Not a general-purpose API; intended only for use by media player service to dump its tracks.
780      */
781             status_t    dump(int fd, const Vector<String16>& args) const;
782 
783     /*
784      * Return the total number of frames which AudioFlinger desired but were unavailable,
785      * and thus which resulted in an underrun.  Reset to zero by stop().
786      */
787             uint32_t    getUnderrunFrames() const;
788 
789     /* Get the flags */
getFlags()790             audio_output_flags_t getFlags() const { AutoMutex _l(mLock); return mFlags; }
791 
792     /* Set parameters - only possible when using direct output */
793             status_t    setParameters(const String8& keyValuePairs);
794 
795     /* Sets the volume shaper object */
796             media::VolumeShaper::Status applyVolumeShaper(
797                     const sp<media::VolumeShaper::Configuration>& configuration,
798                     const sp<media::VolumeShaper::Operation>& operation);
799 
800     /* Gets the volume shaper state */
801             sp<media::VolumeShaper::State> getVolumeShaperState(int id);
802 
803     /* Selects the presentation (if available) */
804             status_t    selectPresentation(int presentationId, int programId);
805 
806     /* Get parameters */
807             String8     getParameters(const String8& keys);
808 
809     /* Poll for a timestamp on demand.
810      * Use if EVENT_NEW_TIMESTAMP is not delivered often enough for your needs,
811      * or if you need to get the most recent timestamp outside of the event callback handler.
812      * Caution: calling this method too often may be inefficient;
813      * if you need a high resolution mapping between frame position and presentation time,
814      * consider implementing that at application level, based on the low resolution timestamps.
815      * Returns NO_ERROR    if timestamp is valid.
816      *         WOULD_BLOCK if called in STOPPED or FLUSHED state, or if called immediately after
817      *                     start/ACTIVE, when the number of frames consumed is less than the
818      *                     overall hardware latency to physical output. In WOULD_BLOCK cases,
819      *                     one might poll again, or use getPosition(), or use 0 position and
820      *                     current time for the timestamp.
821      *         DEAD_OBJECT if AudioFlinger dies or the output device changes and
822      *                     the track cannot be automatically restored.
823      *                     The application needs to recreate the AudioTrack
824      *                     because the audio device changed or AudioFlinger died.
825      *                     This typically occurs for direct or offload tracks
826      *                     or if mDoNotReconnect is true.
827      *         INVALID_OPERATION  wrong state, or some other error.
828      *
829      * The timestamp parameter is undefined on return, if status is not NO_ERROR.
830      */
831             status_t    getTimestamp(AudioTimestamp& timestamp);
832 private:
833             status_t    getTimestamp_l(AudioTimestamp& timestamp);
834 public:
835 
836     /* Return the extended timestamp, with additional timebase info and improved drain behavior.
837      *
838      * This is similar to the AudioTrack.java API:
839      * getTimestamp(@NonNull AudioTimestamp timestamp, @AudioTimestamp.Timebase int timebase)
840      *
841      * Some differences between this method and the getTimestamp(AudioTimestamp& timestamp) method
842      *
843      *   1. stop() by itself does not reset the frame position.
844      *      A following start() resets the frame position to 0.
845      *   2. flush() by itself does not reset the frame position.
846      *      The frame position advances by the number of frames flushed,
847      *      when the first frame after flush reaches the audio sink.
848      *   3. BOOTTIME clock offsets are provided to help synchronize with
849      *      non-audio streams, e.g. sensor data.
850      *   4. Position is returned with 64 bits of resolution.
851      *
852      * Parameters:
853      *  timestamp: A pointer to the caller allocated ExtendedTimestamp.
854      *
855      * Returns NO_ERROR    on success; timestamp is filled with valid data.
856      *         BAD_VALUE   if timestamp is NULL.
857      *         WOULD_BLOCK if called immediately after start() when the number
858      *                     of frames consumed is less than the
859      *                     overall hardware latency to physical output. In WOULD_BLOCK cases,
860      *                     one might poll again, or use getPosition(), or use 0 position and
861      *                     current time for the timestamp.
862      *                     If WOULD_BLOCK is returned, the timestamp is still
863      *                     modified with the LOCATION_CLIENT portion filled.
864      *         DEAD_OBJECT if AudioFlinger dies or the output device changes and
865      *                     the track cannot be automatically restored.
866      *                     The application needs to recreate the AudioTrack
867      *                     because the audio device changed or AudioFlinger died.
868      *                     This typically occurs for direct or offloaded tracks
869      *                     or if mDoNotReconnect is true.
870      *         INVALID_OPERATION  if called on a offloaded or direct track.
871      *                     Use getTimestamp(AudioTimestamp& timestamp) instead.
872      */
873             status_t getTimestamp(ExtendedTimestamp *timestamp);
874 private:
875             status_t getTimestamp_l(ExtendedTimestamp *timestamp);
876 public:
877 
878     /* Add an AudioDeviceCallback. The caller will be notified when the audio device to which this
879      * AudioTrack is routed is updated.
880      * Replaces any previously installed callback.
881      * Parameters:
882      *  callback:  The callback interface
883      * Returns NO_ERROR if successful.
884      *         INVALID_OPERATION if the same callback is already installed.
885      *         NO_INIT or PREMISSION_DENIED if AudioFlinger service is not reachable
886      *         BAD_VALUE if the callback is NULL
887      */
888             status_t addAudioDeviceCallback(const sp<AudioSystem::AudioDeviceCallback>& callback);
889 
890     /* remove an AudioDeviceCallback.
891      * Parameters:
892      *  callback:  The callback interface
893      * Returns NO_ERROR if successful.
894      *         INVALID_OPERATION if the callback is not installed
895      *         BAD_VALUE if the callback is NULL
896      */
897             status_t removeAudioDeviceCallback(
898                     const sp<AudioSystem::AudioDeviceCallback>& callback);
899 
900             // AudioSystem::AudioDeviceCallback> virtuals
901             virtual void onAudioDeviceUpdate(audio_io_handle_t audioIo,
902                                              audio_port_handle_t deviceId);
903 
904     /* Obtain the pending duration in milliseconds for playback of pure PCM
905      * (mixable without embedded timing) data remaining in AudioTrack.
906      *
907      * This is used to estimate the drain time for the client-server buffer
908      * so the choice of ExtendedTimestamp::LOCATION_SERVER is default.
909      * One may optionally request to find the duration to play through the HAL
910      * by specifying a location ExtendedTimestamp::LOCATION_KERNEL; however,
911      * INVALID_OPERATION may be returned if the kernel location is unavailable.
912      *
913      * Returns NO_ERROR  if successful.
914      *         INVALID_OPERATION if ExtendedTimestamp::LOCATION_KERNEL cannot be obtained
915      *                   or the AudioTrack does not contain pure PCM data.
916      *         BAD_VALUE if msec is nullptr or location is invalid.
917      */
918             status_t pendingDuration(int32_t *msec,
919                     ExtendedTimestamp::Location location = ExtendedTimestamp::LOCATION_SERVER);
920 
921     /* hasStarted() is used to determine if audio is now audible at the device after
922      * a start() command. The underlying implementation checks a nonzero timestamp position
923      * or increment for the audible assumption.
924      *
925      * hasStarted() returns true if the track has been started() and audio is audible
926      * and no subsequent pause() or flush() has been called.  Immediately after pause() or
927      * flush() hasStarted() will return false.
928      *
929      * If stop() has been called, hasStarted() will return true if audio is still being
930      * delivered or has finished delivery (even if no audio was written) for both offloaded
931      * and normal tracks. This property removes a race condition in checking hasStarted()
932      * for very short clips, where stop() must be called to finish drain.
933      *
934      * In all cases, hasStarted() may turn false briefly after a subsequent start() is called
935      * until audio becomes audible again.
936      */
937             bool hasStarted(); // not const
938 
isPlaying()939             bool isPlaying() {
940                 AutoMutex lock(mLock);
941                 return mState == STATE_ACTIVE || mState == STATE_STOPPING;
942             }
943 
944     /* Get the unique port ID assigned to this AudioTrack instance by audio policy manager.
945      * The ID is unique across all audioserver clients and can change during the life cycle
946      * of a given AudioTrack instance if the connection to audioserver is restored.
947      */
getPortId()948             audio_port_handle_t getPortId() const { return mPortId; };
949 
setAudioTrackCallback(const sp<media::IAudioTrackCallback> & callback)950             void setAudioTrackCallback(const sp<media::IAudioTrackCallback>& callback) {
951                 mAudioTrackCallback->setAudioTrackCallback(callback);
952             }
953 
954  protected:
955     /* copying audio tracks is not allowed */
956                         AudioTrack(const AudioTrack& other);
957             AudioTrack& operator = (const AudioTrack& other);
958 
959     /* a small internal class to handle the callback */
960     class AudioTrackThread : public Thread
961     {
962     public:
963         explicit AudioTrackThread(AudioTrack& receiver);
964 
965         // Do not call Thread::requestExitAndWait() without first calling requestExit().
966         // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough.
967         virtual void        requestExit();
968 
969                 void        pause();    // suspend thread from execution at next loop boundary
970                 void        resume();   // allow thread to execute, if not requested to exit
971                 void        wake();     // wake to handle changed notification conditions.
972 
973     private:
974                 void        pauseInternal(nsecs_t ns = 0LL);
975                                         // like pause(), but only used internally within thread
976 
977         friend class AudioTrack;
978         virtual bool        threadLoop();
979         AudioTrack&         mReceiver;
980         virtual ~AudioTrackThread();
981         Mutex               mMyLock;    // Thread::mLock is private
982         Condition           mMyCond;    // Thread::mThreadExitedCondition is private
983         bool                mPaused;    // whether thread is requested to pause at next loop entry
984         bool                mPausedInt; // whether thread internally requests pause
985         nsecs_t             mPausedNs;  // if mPausedInt then associated timeout, otherwise ignored
986         bool                mIgnoreNextPausedInt;   // skip any internal pause and go immediately
987                                         // to processAudioBuffer() as state may have changed
988                                         // since pause time calculated.
989     };
990 
991             // body of AudioTrackThread::threadLoop()
992             // returns the maximum amount of time before we would like to run again, where:
993             //      0           immediately
994             //      > 0         no later than this many nanoseconds from now
995             //      NS_WHENEVER still active but no particular deadline
996             //      NS_INACTIVE inactive so don't run again until re-started
997             //      NS_NEVER    never again
998             static const nsecs_t NS_WHENEVER = -1, NS_INACTIVE = -2, NS_NEVER = -3;
999             nsecs_t processAudioBuffer();
1000 
1001             // caller must hold lock on mLock for all _l methods
1002 
1003             void updateLatency_l(); // updates mAfLatency and mLatency from AudioSystem cache
1004 
1005             status_t createTrack_l();
1006 
1007             // can only be called when mState != STATE_ACTIVE
1008             void flush_l();
1009 
1010             void setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);
1011 
1012             // FIXME enum is faster than strcmp() for parameter 'from'
1013             status_t restoreTrack_l(const char *from);
1014 
1015             uint32_t    getUnderrunCount_l() const;
1016 
1017             bool     isOffloaded() const;
1018             bool     isDirect() const;
1019             bool     isOffloadedOrDirect() const;
1020 
isOffloaded_l()1021             bool     isOffloaded_l() const
1022                 { return (mFlags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) != 0; }
1023 
isOffloadedOrDirect_l()1024             bool     isOffloadedOrDirect_l() const
1025                 { return (mFlags & (AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD|
1026                                                 AUDIO_OUTPUT_FLAG_DIRECT)) != 0; }
1027 
isDirect_l()1028             bool     isDirect_l() const
1029                 { return (mFlags & AUDIO_OUTPUT_FLAG_DIRECT) != 0; }
1030 
1031             // pure pcm data is mixable (which excludes HW_AV_SYNC, with embedded timing)
isPurePcmData_l()1032             bool     isPurePcmData_l() const
1033                 { return audio_is_linear_pcm(mFormat)
1034                         && (mAttributes.flags & AUDIO_FLAG_HW_AV_SYNC) == 0; }
1035 
1036             // increment mPosition by the delta of mServer, and return new value of mPosition
1037             Modulo<uint32_t> updateAndGetPosition_l();
1038 
1039             // check sample rate and speed is compatible with AudioTrack
1040             bool     isSampleRateSpeedAllowed_l(uint32_t sampleRate, float speed);
1041 
1042             void     restartIfDisabled();
1043 
1044             void     updateRoutedDeviceId_l();
1045 
1046     // Next 4 fields may be changed if IAudioTrack is re-created, but always != 0
1047     sp<IAudioTrack>         mAudioTrack;
1048     sp<IMemory>             mCblkMemory;
1049     audio_track_cblk_t*     mCblk;                  // re-load after mLock.unlock()
1050     audio_io_handle_t       mOutput = AUDIO_IO_HANDLE_NONE; // from AudioSystem::getOutputForAttr()
1051 
1052     sp<AudioTrackThread>    mAudioTrackThread;
1053     bool                    mThreadCanCallJava;
1054 
1055     float                   mVolume[2];
1056     float                   mSendLevel;
1057     mutable uint32_t        mSampleRate;            // mutable because getSampleRate() can update it
1058     uint32_t                mOriginalSampleRate;
1059     AudioPlaybackRate       mPlaybackRate;
1060     float                   mMaxRequiredSpeed;      // use PCM buffer size to allow this speed
1061 
1062     // Corresponds to current IAudioTrack, value is reported back by AudioFlinger to the client.
1063     // This allocated buffer size is maintained by the proxy.
1064     size_t                  mFrameCount;            // maximum size of buffer
1065 
1066     size_t                  mReqFrameCount;         // frame count to request the first or next time
1067                                                     // a new IAudioTrack is needed, non-decreasing
1068 
1069     // The following AudioFlinger server-side values are cached in createAudioTrack_l().
1070     // These values can be used for informational purposes until the track is invalidated,
1071     // whereupon restoreTrack_l() calls createTrack_l() to update the values.
1072     uint32_t                mAfLatency;             // AudioFlinger latency in ms
1073     size_t                  mAfFrameCount;          // AudioFlinger frame count
1074     uint32_t                mAfSampleRate;          // AudioFlinger sample rate
1075 
1076     // constant after constructor or set()
1077     audio_format_t          mFormat;                // as requested by client, not forced to 16-bit
1078     audio_stream_type_t     mStreamType;            // mStreamType == AUDIO_STREAM_DEFAULT implies
1079                                                     // this AudioTrack has valid attributes
1080     uint32_t                mChannelCount;
1081     audio_channel_mask_t    mChannelMask;
1082     sp<IMemory>             mSharedBuffer;
1083     transfer_type           mTransfer;
1084     audio_offload_info_t    mOffloadInfoCopy;
1085     const audio_offload_info_t* mOffloadInfo;
1086     audio_attributes_t      mAttributes;
1087 
1088     size_t                  mFrameSize;             // frame size in bytes
1089 
1090     status_t                mStatus;
1091 
1092     // can change dynamically when IAudioTrack invalidated
1093     uint32_t                mLatency;               // in ms
1094 
1095     // Indicates the current track state.  Protected by mLock.
1096     enum State {
1097         STATE_ACTIVE,
1098         STATE_STOPPED,
1099         STATE_PAUSED,
1100         STATE_PAUSED_STOPPING,
1101         STATE_FLUSHED,
1102         STATE_STOPPING,
1103     }                       mState;
1104 
stateToString(State state)1105     static constexpr const char *stateToString(State state)
1106     {
1107         switch (state) {
1108         case STATE_ACTIVE:          return "STATE_ACTIVE";
1109         case STATE_STOPPED:         return "STATE_STOPPED";
1110         case STATE_PAUSED:          return "STATE_PAUSED";
1111         case STATE_PAUSED_STOPPING: return "STATE_PAUSED_STOPPING";
1112         case STATE_FLUSHED:         return "STATE_FLUSHED";
1113         case STATE_STOPPING:        return "STATE_STOPPING";
1114         default:                    return "UNKNOWN";
1115         }
1116     }
1117 
1118     // for client callback handler
1119     callback_t              mCbf;                   // callback handler for events, or NULL
1120     void*                   mUserData;
1121 
1122     // for notification APIs
1123 
1124     // next 2 fields are const after constructor or set()
1125     uint32_t                mNotificationFramesReq; // requested number of frames between each
1126                                                     // notification callback,
1127                                                     // at initial source sample rate
1128     uint32_t                mNotificationsPerBufferReq;
1129                                                     // requested number of notifications per buffer,
1130                                                     // currently only used for fast tracks with
1131                                                     // default track buffer size
1132 
1133     uint32_t                mNotificationFramesAct; // actual number of frames between each
1134                                                     // notification callback,
1135                                                     // at initial source sample rate
1136     bool                    mRefreshRemaining;      // processAudioBuffer() should refresh
1137                                                     // mRemainingFrames and mRetryOnPartialBuffer
1138 
1139                                                     // used for static track cbf and restoration
1140     int32_t                 mLoopCount;             // last setLoop loopCount; zero means disabled
1141     uint32_t                mLoopStart;             // last setLoop loopStart
1142     uint32_t                mLoopEnd;               // last setLoop loopEnd
1143     int32_t                 mLoopCountNotified;     // the last loopCount notified by callback.
1144                                                     // mLoopCountNotified counts down, matching
1145                                                     // the remaining loop count for static track
1146                                                     // playback.
1147 
1148     // These are private to processAudioBuffer(), and are not protected by a lock
1149     uint32_t                mRemainingFrames;       // number of frames to request in obtainBuffer()
1150     bool                    mRetryOnPartialBuffer;  // sleep and retry after partial obtainBuffer()
1151     uint32_t                mObservedSequence;      // last observed value of mSequence
1152 
1153     Modulo<uint32_t>        mMarkerPosition;        // in wrapping (overflow) frame units
1154     bool                    mMarkerReached;
1155     Modulo<uint32_t>        mNewPosition;           // in frames
1156     uint32_t                mUpdatePeriod;          // in frames, zero means no EVENT_NEW_POS
1157 
1158     Modulo<uint32_t>        mServer;                // in frames, last known mProxy->getPosition()
1159                                                     // which is count of frames consumed by server,
1160                                                     // reset by new IAudioTrack,
1161                                                     // whether it is reset by stop() is TBD
1162     Modulo<uint32_t>        mPosition;              // in frames, like mServer except continues
1163                                                     // monotonically after new IAudioTrack,
1164                                                     // and could be easily widened to uint64_t
1165     Modulo<uint32_t>        mReleased;              // count of frames released to server
1166                                                     // but not necessarily consumed by server,
1167                                                     // reset by stop() but continues monotonically
1168                                                     // after new IAudioTrack to restore mPosition,
1169                                                     // and could be easily widened to uint64_t
1170     int64_t                 mStartFromZeroUs;       // the start time after flush or stop,
1171                                                     // when position should be 0.
1172                                                     // only used for offloaded and direct tracks.
1173     int64_t                 mStartNs;               // the time when start() is called.
1174     ExtendedTimestamp       mStartEts;              // Extended timestamp at start for normal
1175                                                     // AudioTracks.
1176     AudioTimestamp          mStartTs;               // Timestamp at start for offloaded or direct
1177                                                     // AudioTracks.
1178 
1179     bool                    mPreviousTimestampValid;// true if mPreviousTimestamp is valid
1180     bool                    mTimestampStartupGlitchReported;      // reduce log spam
1181     bool                    mTimestampRetrogradePositionReported; // reduce log spam
1182     bool                    mTimestampRetrogradeTimeReported;     // reduce log spam
1183     bool                    mTimestampStallReported;              // reduce log spam
1184     bool                    mTimestampStaleTimeReported;          // reduce log spam
1185     AudioTimestamp          mPreviousTimestamp;     // used to detect retrograde motion
1186     ExtendedTimestamp::Location mPreviousLocation;  // location used for previous timestamp
1187 
1188     uint32_t                mUnderrunCountOffset;   // updated when restoring tracks
1189 
1190     int64_t                 mFramesWritten;         // total frames written. reset to zero after
1191                                                     // the start() following stop(). It is not
1192                                                     // changed after restoring the track or
1193                                                     // after flush.
1194     int64_t                 mFramesWrittenServerOffset; // An offset to server frames due to
1195                                                     // restoring AudioTrack, or stop/start.
1196                                                     // This offset is also used for static tracks.
1197     int64_t                 mFramesWrittenAtRestore; // Frames written at restore point (or frames
1198                                                     // delivered for static tracks).
1199                                                     // -1 indicates no previous restore point.
1200 
1201     audio_output_flags_t    mFlags;                 // same as mOrigFlags, except for bits that may
1202                                                     // be denied by client or server, such as
1203                                                     // AUDIO_OUTPUT_FLAG_FAST.  mLock must be
1204                                                     // held to read or write those bits reliably.
1205     audio_output_flags_t    mOrigFlags;             // as specified in constructor or set(), const
1206 
1207     bool                    mDoNotReconnect;
1208 
1209     audio_session_t         mSessionId;
1210     int                     mAuxEffectId;
1211     audio_port_handle_t     mPortId;                    // Id from Audio Policy Manager
1212 
1213     mutable Mutex           mLock;
1214 
1215     int                     mPreviousPriority;          // before start()
1216     SchedPolicy             mPreviousSchedulingGroup;
1217     bool                    mAwaitBoost;    // thread should wait for priority boost before running
1218 
1219     // The proxy should only be referenced while a lock is held because the proxy isn't
1220     // multi-thread safe, especially the SingleStateQueue part of the proxy.
1221     // An exception is that a blocking ClientProxy::obtainBuffer() may be called without a lock,
1222     // provided that the caller also holds an extra reference to the proxy and shared memory to keep
1223     // them around in case they are replaced during the obtainBuffer().
1224     sp<StaticAudioTrackClientProxy> mStaticProxy;   // for type safety only
1225     sp<AudioTrackClientProxy>       mProxy;         // primary owner of the memory
1226 
1227     bool                    mInUnderrun;            // whether track is currently in underrun state
1228     uint32_t                mPausedPosition;
1229 
1230     // For Device Selection API
1231     //  a value of AUDIO_PORT_HANDLE_NONE indicated default (AudioPolicyManager) routing.
1232     audio_port_handle_t    mSelectedDeviceId; // Device requested by the application.
1233     audio_port_handle_t    mRoutedDeviceId;   // Device actually selected by audio policy manager:
1234                                               // May not match the app selection depending on other
1235                                               // activity and connected devices.
1236 
1237     sp<media::VolumeHandler>       mVolumeHandler;
1238 
1239 private:
1240     class DeathNotifier : public IBinder::DeathRecipient {
1241     public:
DeathNotifier(AudioTrack * audioTrack)1242         explicit DeathNotifier(AudioTrack* audioTrack) : mAudioTrack(audioTrack) { }
1243     protected:
1244         virtual void        binderDied(const wp<IBinder>& who);
1245     private:
1246         const wp<AudioTrack> mAudioTrack;
1247     };
1248 
1249     sp<DeathNotifier>       mDeathNotifier;
1250     uint32_t                mSequence;              // incremented for each new IAudioTrack attempt
1251     uid_t                   mClientUid;
1252     pid_t                   mClientPid;
1253 
1254     wp<AudioSystem::AudioDeviceCallback> mDeviceCallback;
1255 
1256 private:
1257     class MediaMetrics {
1258       public:
MediaMetrics()1259         MediaMetrics() : mMetricsItem(mediametrics::Item::create("audiotrack")) {
1260         }
~MediaMetrics()1261         ~MediaMetrics() {
1262             // mMetricsItem alloc failure will be flagged in the constructor
1263             // don't log empty records
1264             if (mMetricsItem->count() > 0) {
1265                 mMetricsItem->selfrecord();
1266             }
1267         }
1268         void gather(const AudioTrack *track);
dup()1269         mediametrics::Item *dup() { return mMetricsItem->dup(); }
1270       private:
1271         std::unique_ptr<mediametrics::Item> mMetricsItem;
1272     };
1273     MediaMetrics mMediaMetrics;
1274     std::string mMetricsId;  // GUARDED_BY(mLock), could change in createTrack_l().
1275     std::string mCallerName; // for example "aaudio"
1276 
1277 private:
1278     class AudioTrackCallback : public media::BnAudioTrackCallback {
1279     public:
1280         binder::Status onCodecFormatChanged(const std::vector<uint8_t>& audioMetadata) override;
1281 
1282         void setAudioTrackCallback(const sp<media::IAudioTrackCallback>& callback);
1283     private:
1284         Mutex mAudioTrackCbLock;
1285         wp<media::IAudioTrackCallback> mCallback;
1286     };
1287     sp<AudioTrackCallback> mAudioTrackCallback;
1288 };
1289 
1290 }; // namespace android
1291 
1292 #endif // ANDROID_AUDIOTRACK_H
1293