AudioTrack.h revision 520a9af9438c29b24e328dd2b7a287c7a96a4e6b
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 <stdint.h> 21#include <sys/types.h> 22 23#include <media/IAudioFlinger.h> 24#include <media/IAudioTrack.h> 25#include <media/AudioSystem.h> 26 27#include <utils/RefBase.h> 28#include <utils/Errors.h> 29#include <binder/IInterface.h> 30#include <binder/IMemory.h> 31#include <cutils/sched_policy.h> 32#include <utils/threads.h> 33 34namespace android { 35 36// ---------------------------------------------------------------------------- 37 38class audio_track_cblk_t; 39 40// ---------------------------------------------------------------------------- 41 42class AudioTrack : virtual public RefBase 43{ 44public: 45 enum channel_index { 46 MONO = 0, 47 LEFT = 0, 48 RIGHT = 1 49 }; 50 51 /* Events used by AudioTrack callback function (audio_track_cblk_t). 52 * Keep in sync with frameworks/base/media/java/android/media/AudioTrack.java NATIVE_EVENT_*. 53 */ 54 enum event_type { 55 EVENT_MORE_DATA = 0, // Request to write more data to PCM buffer. 56 EVENT_UNDERRUN = 1, // PCM buffer underrun occurred. 57 EVENT_LOOP_END = 2, // Sample loop end was reached; playback restarted from 58 // loop start if loop count was not 0. 59 EVENT_MARKER = 3, // Playback head is at the specified marker position 60 // (See setMarkerPosition()). 61 EVENT_NEW_POS = 4, // Playback head is at a new position 62 // (See setPositionUpdatePeriod()). 63 EVENT_BUFFER_END = 5 // Playback head is at the end of the buffer. 64 }; 65 66 /* Client should declare Buffer on the stack and pass address to obtainBuffer() 67 * and releaseBuffer(). See also callback_t for EVENT_MORE_DATA. 68 */ 69 70 class Buffer 71 { 72 public: 73 size_t frameCount; // number of sample frames corresponding to size; 74 // on input it is the number of frames desired, 75 // on output is the number of frames actually filled 76 77 size_t size; // input/output in byte units 78 union { 79 void* raw; 80 short* i16; // signed 16-bit 81 int8_t* i8; // unsigned 8-bit, offset by 0x80 82 }; 83 }; 84 85 86 /* As a convenience, if a callback is supplied, a handler thread 87 * is automatically created with the appropriate priority. This thread 88 * invokes the callback when a new buffer becomes available or various conditions occur. 89 * Parameters: 90 * 91 * event: type of event notified (see enum AudioTrack::event_type). 92 * user: Pointer to context for use by the callback receiver. 93 * info: Pointer to optional parameter according to event type: 94 * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write 95 * more bytes than indicated by 'size' field and update 'size' if fewer bytes are 96 * written. 97 * - EVENT_UNDERRUN: unused. 98 * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. 99 * - EVENT_MARKER: pointer to an uint32_t containing the marker position in frames. 100 * - EVENT_NEW_POS: pointer to an uint32_t containing the new position in frames. 101 * - EVENT_BUFFER_END: unused. 102 */ 103 104 typedef void (*callback_t)(int event, void* user, void *info); 105 106 /* Returns the minimum frame count required for the successful creation of 107 * an AudioTrack object. 108 * Returned status (from utils/Errors.h) can be: 109 * - NO_ERROR: successful operation 110 * - NO_INIT: audio server or audio hardware not initialized 111 */ 112 113 static status_t getMinFrameCount(int* frameCount, 114 audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 115 uint32_t sampleRate = 0); 116 117 /* Constructs an uninitialized AudioTrack. No connection with 118 * AudioFlinger takes place. 119 */ 120 AudioTrack(); 121 122 /* Creates an AudioTrack object and registers it with AudioFlinger. 123 * Once created, the track needs to be started before it can be used. 124 * Unspecified values are set to the audio hardware's current 125 * values. 126 * 127 * Parameters: 128 * 129 * streamType: Select the type of audio stream this track is attached to 130 * (e.g. AUDIO_STREAM_MUSIC). 131 * sampleRate: Track sampling rate in Hz. 132 * format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed 133 * 16 bits per sample). 134 * channelMask: Channel mask. 135 * frameCount: Minimum size of track PCM buffer in frames. This defines the 136 * application's contribution to the 137 * latency of the track. The actual size selected by the AudioTrack could be 138 * larger if the requested size is not compatible with current audio HAL 139 * latency. Zero means to use a default value. 140 * flags: See comments on audio_output_flags_t in <system/audio.h>. 141 * cbf: Callback function. If not null, this function is called periodically 142 * to provide new PCM data. 143 * user: Context for use by the callback receiver. 144 * notificationFrames: The callback function is called each time notificationFrames PCM 145 * frames have been consumed from track input buffer. 146 * sessionId: Specific session ID, or zero to use default. 147 * threadCanCallJava: Whether callbacks are made from an attached thread and thus can call JNI. 148 * If not present in parameter list, then fixed at false. 149 */ 150 151 AudioTrack( audio_stream_type_t streamType, 152 uint32_t sampleRate = 0, 153 audio_format_t format = AUDIO_FORMAT_DEFAULT, 154 audio_channel_mask_t channelMask = 0, 155 int frameCount = 0, 156 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 157 callback_t cbf = NULL, 158 void* user = NULL, 159 int notificationFrames = 0, 160 int sessionId = 0); 161 162 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 163 * the PCM data to be rendered by AudioTrack is passed in a shared memory buffer 164 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 165 * PCM data must be present in memory before the AudioTrack is started. 166 * The write() and flush() methods are not supported in this case. 167 * It is recommended to pass a callback function to be notified of playback end by an 168 * EVENT_UNDERRUN event. 169 */ 170 171 AudioTrack( audio_stream_type_t streamType, 172 uint32_t sampleRate = 0, 173 audio_format_t format = AUDIO_FORMAT_DEFAULT, 174 audio_channel_mask_t channelMask = 0, 175 const sp<IMemory>& sharedBuffer = 0, 176 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 177 callback_t cbf = NULL, 178 void* user = NULL, 179 int notificationFrames = 0, 180 int sessionId = 0); 181 182 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 183 * Also destroys all resources associated with the AudioTrack. 184 */ 185 ~AudioTrack(); 186 187 188 /* Initialize an uninitialized AudioTrack. 189 * Returned status (from utils/Errors.h) can be: 190 * - NO_ERROR: successful initialization 191 * - INVALID_OPERATION: AudioTrack is already initialized 192 * - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...) 193 * - NO_INIT: audio server or audio hardware not initialized 194 */ 195 status_t set(audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 196 uint32_t sampleRate = 0, 197 audio_format_t format = AUDIO_FORMAT_DEFAULT, 198 audio_channel_mask_t channelMask = 0, 199 int frameCount = 0, 200 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 201 callback_t cbf = NULL, 202 void* user = NULL, 203 int notificationFrames = 0, 204 const sp<IMemory>& sharedBuffer = 0, 205 bool threadCanCallJava = false, 206 int sessionId = 0); 207 208 209 /* Result of constructing the AudioTrack. This must be checked 210 * before using any AudioTrack API (except for set()), because using 211 * an uninitialized AudioTrack produces undefined results. 212 * See set() method above for possible return codes. 213 */ 214 status_t initCheck() const; 215 216 /* Returns this track's estimated latency in milliseconds. 217 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 218 * and audio hardware driver. 219 */ 220 uint32_t latency() const; 221 222 /* getters, see constructors and set() */ 223 224 audio_stream_type_t streamType() const; 225 audio_format_t format() const; 226 int channelCount() const; 227 uint32_t frameCount() const; 228 229 /* Return channelCount * (bit depth per channel / 8). 230 * channelCount is determined from channelMask, and bit depth comes from format. 231 */ 232 size_t frameSize() const { return mFrameSize; } 233 234 sp<IMemory>& sharedBuffer(); 235 236 237 /* After it's created the track is not active. Call start() to 238 * make it active. If set, the callback will start being called. 239 */ 240 void start(); 241 242 /* Stop a track. If set, the callback will cease being called and 243 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 244 * and will fill up buffers until the pool is exhausted. 245 */ 246 void stop(); 247 bool stopped() const; 248 249 /* Flush a stopped track. All pending buffers are discarded. 250 * This function has no effect if the track is not stopped. 251 */ 252 void flush(); 253 254 /* Pause a track. If set, the callback will cease being called and 255 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 256 * and will fill up buffers until the pool is exhausted. 257 */ 258 void pause(); 259 260 /* Mute or unmute this track. 261 * While muted, the callback, if set, is still called. 262 */ 263 void mute(bool); 264 bool muted() const; 265 266 /* Set volume for this track, mostly used for games' sound effects 267 * left and right volumes. Levels must be >= 0.0 and <= 1.0. 268 * This is the older API. New applications should use setVolume(float) when possible. 269 */ 270 status_t setVolume(float left, float right); 271 272 /* Set volume for all channels. This is the preferred API for new applications, 273 * especially for multi-channel content. 274 */ 275 status_t setVolume(float volume); 276 277 /* Set the send level for this track. An auxiliary effect should be attached 278 * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0. 279 */ 280 status_t setAuxEffectSendLevel(float level); 281 void getAuxEffectSendLevel(float* level) const; 282 283 /* Set sample rate for this track in Hz, mostly used for games' sound effects 284 */ 285 status_t setSampleRate(uint32_t sampleRate); 286 287 /* Return current sample rate in Hz, or 0 if unknown */ 288 uint32_t getSampleRate() const; 289 290 /* Enables looping and sets the start and end points of looping. 291 * 292 * Parameters: 293 * 294 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 295 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 296 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any 297 * pending or active loop. loopCount = -1 means infinite looping. 298 * 299 * For proper operation the following condition must be respected: 300 * (loopEnd-loopStart) <= framecount() 301 */ 302 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 303 304 /* Sets marker position. When playback reaches the number of frames specified, a callback with 305 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 306 * notification callback. 307 * If the AudioTrack has been opened with no callback function associated, the operation will 308 * fail. 309 * 310 * Parameters: 311 * 312 * marker: marker position expressed in frames. 313 * 314 * Returned status (from utils/Errors.h) can be: 315 * - NO_ERROR: successful operation 316 * - INVALID_OPERATION: the AudioTrack has no callback installed. 317 */ 318 status_t setMarkerPosition(uint32_t marker); 319 status_t getMarkerPosition(uint32_t *marker) const; 320 321 322 /* Sets position update period. Every time the number of frames specified has been played, 323 * a callback with event type EVENT_NEW_POS is called. 324 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 325 * callback. 326 * If the AudioTrack has been opened with no callback function associated, the operation will 327 * fail. 328 * 329 * Parameters: 330 * 331 * updatePeriod: position update notification period expressed in frames. 332 * 333 * Returned status (from utils/Errors.h) can be: 334 * - NO_ERROR: successful operation 335 * - INVALID_OPERATION: the AudioTrack has no callback installed. 336 */ 337 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 338 status_t getPositionUpdatePeriod(uint32_t *updatePeriod) const; 339 340 /* Sets playback head position within AudioTrack buffer. The new position is specified 341 * in number of frames. 342 * This method must be called with the AudioTrack in paused or stopped state. 343 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 344 * Therefore using this method makes sense only when playing a "static" audio buffer 345 * as opposed to streaming. 346 * The getPosition() method on the other hand returns the total number of frames played since 347 * playback start. 348 * 349 * Parameters: 350 * 351 * position: New playback head position within AudioTrack buffer. 352 * 353 * Returned status (from utils/Errors.h) can be: 354 * - NO_ERROR: successful operation 355 * - INVALID_OPERATION: the AudioTrack is not stopped. 356 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack 357 * buffer 358 */ 359 status_t setPosition(uint32_t position); 360 status_t getPosition(uint32_t *position); 361 362 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 363 * rewriting the buffer before restarting playback after a stop. 364 * This method must be called with the AudioTrack in paused or stopped state. 365 * 366 * Returned status (from utils/Errors.h) can be: 367 * - NO_ERROR: successful operation 368 * - INVALID_OPERATION: the AudioTrack is not stopped. 369 */ 370 status_t reload(); 371 372 /* Returns a handle on the audio output used by this AudioTrack. 373 * 374 * Parameters: 375 * none. 376 * 377 * Returned value: 378 * handle on audio hardware output 379 */ 380 audio_io_handle_t getOutput(); 381 382 /* Returns the unique session ID associated with this track. 383 * 384 * Parameters: 385 * none. 386 * 387 * Returned value: 388 * AudioTrack session ID. 389 */ 390 int getSessionId() const; 391 392 /* Attach track auxiliary output to specified effect. Use effectId = 0 393 * to detach track from effect. 394 * 395 * Parameters: 396 * 397 * effectId: effectId obtained from AudioEffect::id(). 398 * 399 * Returned status (from utils/Errors.h) can be: 400 * - NO_ERROR: successful operation 401 * - INVALID_OPERATION: the effect is not an auxiliary effect. 402 * - BAD_VALUE: The specified effect ID is invalid 403 */ 404 status_t attachAuxEffect(int effectId); 405 406 /* Obtains a buffer of "frameCount" frames. The buffer must be 407 * filled entirely, and then released with releaseBuffer(). 408 * If the track is stopped, obtainBuffer() returns 409 * STOPPED instead of NO_ERROR as long as there are buffers available, 410 * at which point NO_MORE_BUFFERS is returned. 411 * Buffers will be returned until the pool 412 * is exhausted, at which point obtainBuffer() will either block 413 * or return WOULD_BLOCK depending on the value of the "blocking" 414 * parameter. 415 * 416 * Interpretation of waitCount: 417 * +n limits wait time to n * WAIT_PERIOD_MS, 418 * -1 causes an (almost) infinite wait time, 419 * 0 non-blocking. 420 * 421 * Buffer fields 422 * On entry: 423 * frameCount number of frames requested 424 * After error return: 425 * frameCount 0 426 * size 0 427 * raw undefined 428 * After successful return: 429 * frameCount actual number of frames available, <= number requested 430 * size actual number of bytes available 431 * raw pointer to the buffer 432 */ 433 434 enum { 435 NO_MORE_BUFFERS = 0x80000001, // same name in AudioFlinger.h, ok to be different value 436 STOPPED = 1 437 }; 438 439 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 440 441 /* Release a filled buffer of "frameCount" frames for AudioFlinger to process. */ 442 void releaseBuffer(Buffer* audioBuffer); 443 444 /* As a convenience we provide a write() interface to the audio buffer. 445 * This is implemented on top of obtainBuffer/releaseBuffer. For best 446 * performance use callbacks. Returns actual number of bytes written >= 0, 447 * or one of the following negative status codes: 448 * INVALID_OPERATION AudioTrack is configured for shared buffer mode 449 * BAD_VALUE size is invalid 450 * STOPPED AudioTrack was stopped during the write 451 * NO_MORE_BUFFERS when obtainBuffer() returns same 452 * or any other error code returned by IAudioTrack::start() or restoreTrack_l(). 453 */ 454 ssize_t write(const void* buffer, size_t size); 455 456 /* 457 * Dumps the state of an audio track. 458 */ 459 status_t dump(int fd, const Vector<String16>& args) const; 460 461protected: 462 /* copying audio tracks is not allowed */ 463 AudioTrack(const AudioTrack& other); 464 AudioTrack& operator = (const AudioTrack& other); 465 466 /* a small internal class to handle the callback */ 467 class AudioTrackThread : public Thread 468 { 469 public: 470 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 471 472 // Do not call Thread::requestExitAndWait() without first calling requestExit(). 473 // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough. 474 virtual void requestExit(); 475 476 void pause(); // suspend thread from execution at next loop boundary 477 void resume(); // allow thread to execute, if not requested to exit 478 479 private: 480 friend class AudioTrack; 481 virtual bool threadLoop(); 482 AudioTrack& mReceiver; 483 ~AudioTrackThread(); 484 Mutex mMyLock; // Thread::mLock is private 485 Condition mMyCond; // Thread::mThreadExitedCondition is private 486 bool mPaused; // whether thread is currently paused 487 }; 488 489 // body of AudioTrackThread::threadLoop() 490 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 491 492 // caller must hold lock on mLock for all _l methods 493 status_t createTrack_l(audio_stream_type_t streamType, 494 uint32_t sampleRate, 495 audio_format_t format, 496 audio_channel_mask_t channelMask, 497 int frameCount, 498 audio_output_flags_t flags, 499 const sp<IMemory>& sharedBuffer, 500 audio_io_handle_t output); 501 void flush_l(); 502 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 503 audio_io_handle_t getOutput_l(); 504 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 505 bool stopped_l() const { return !mActive; } 506 507 sp<IAudioTrack> mAudioTrack; 508 sp<IMemory> mCblkMemory; 509 sp<AudioTrackThread> mAudioTrackThread; 510 511 float mVolume[2]; 512 float mSendLevel; 513 uint32_t mFrameCount; 514 515 audio_track_cblk_t* mCblk; // re-load after mLock.unlock() 516 517 // Starting address of buffers in shared memory. If there is a shared buffer, mBuffers 518 // is the value of pointer() for the shared buffer, otherwise mBuffers points 519 // immediately after the control block. This address is for the mapping within client 520 // address space. AudioFlinger::TrackBase::mBuffer is for the server address space. 521 void* mBuffers; 522 523 audio_format_t mFormat; // as requested by client, not forced to 16-bit 524 audio_stream_type_t mStreamType; 525 uint8_t mChannelCount; 526 uint8_t mMuted; 527 uint8_t mReserved; 528 audio_channel_mask_t mChannelMask; 529 530 // mFrameSize is equal to mFrameSizeAF for non-PCM or 16-bit PCM data. 531 // For 8-bit PCM data, mFrameSizeAF is 532 // twice as large because data is expanded to 16-bit before being stored in buffer. 533 size_t mFrameSize; // app-level frame size 534 size_t mFrameSizeAF; // AudioFlinger frame size 535 536 status_t mStatus; 537 uint32_t mLatency; 538 539 bool mActive; // protected by mLock 540 541 callback_t mCbf; // callback handler for events, or NULL 542 void* mUserData; // for client callback handler 543 544 // for notification APIs 545 uint32_t mNotificationFramesReq; // requested number of frames between each 546 // notification callback 547 uint32_t mNotificationFramesAct; // actual number of frames between each 548 // notification callback 549 sp<IMemory> mSharedBuffer; 550 int mLoopCount; 551 uint32_t mRemainingFrames; 552 uint32_t mMarkerPosition; // in frames 553 bool mMarkerReached; 554 uint32_t mNewPosition; // in frames 555 uint32_t mUpdatePeriod; // in frames 556 557 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 558 audio_output_flags_t mFlags; 559 int mSessionId; 560 int mAuxEffectId; 561 562 // When locking both mLock and mCblk->lock, must lock in this order to avoid deadlock: 563 // 1. mLock 564 // 2. mCblk->lock 565 // It is OK to lock only mCblk->lock. 566 mutable Mutex mLock; 567 568 bool mIsTimed; 569 int mPreviousPriority; // before start() 570 SchedPolicy mPreviousSchedulingGroup; 571}; 572 573class TimedAudioTrack : public AudioTrack 574{ 575public: 576 TimedAudioTrack(); 577 578 /* allocate a shared memory buffer that can be passed to queueTimedBuffer */ 579 status_t allocateTimedBuffer(size_t size, sp<IMemory>* buffer); 580 581 /* queue a buffer obtained via allocateTimedBuffer for playback at the 582 given timestamp. PTS units are microseconds on the media time timeline. 583 The media time transform (set with setMediaTimeTransform) set by the 584 audio producer will handle converting from media time to local time 585 (perhaps going through the common time timeline in the case of 586 synchronized multiroom audio case) */ 587 status_t queueTimedBuffer(const sp<IMemory>& buffer, int64_t pts); 588 589 /* define a transform between media time and either common time or 590 local time */ 591 enum TargetTimeline {LOCAL_TIME, COMMON_TIME}; 592 status_t setMediaTimeTransform(const LinearTransform& xform, 593 TargetTimeline target); 594}; 595 596}; // namespace android 597 598#endif // ANDROID_AUDIOTRACK_H 599