AudioTrack.h revision a96bd95dcfe886436652debbda77ceb634729da0
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; 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 */ 269 status_t setVolume(float left, float right); 270 void getVolume(float* left, float* right) const; 271 272 /* Set the send level for this track. An auxiliary effect should be attached 273 * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0. 274 */ 275 status_t setAuxEffectSendLevel(float level); 276 void getAuxEffectSendLevel(float* level) const; 277 278 /* Set sample rate for this track in Hz, mostly used for games' sound effects 279 */ 280 status_t setSampleRate(int sampleRate); 281 uint32_t getSampleRate() const; 282 283 /* Enables looping and sets the start and end points of looping. 284 * 285 * Parameters: 286 * 287 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 288 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 289 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any 290 * pending or active loop. loopCount = -1 means infinite looping. 291 * 292 * For proper operation the following condition must be respected: 293 * (loopEnd-loopStart) <= framecount() 294 */ 295 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 296 297 /* Sets marker position. When playback reaches the number of frames specified, a callback with 298 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 299 * notification callback. 300 * If the AudioTrack has been opened with no callback function associated, the operation will 301 * fail. 302 * 303 * Parameters: 304 * 305 * marker: marker position expressed in frames. 306 * 307 * Returned status (from utils/Errors.h) can be: 308 * - NO_ERROR: successful operation 309 * - INVALID_OPERATION: the AudioTrack has no callback installed. 310 */ 311 status_t setMarkerPosition(uint32_t marker); 312 status_t getMarkerPosition(uint32_t *marker) const; 313 314 315 /* Sets position update period. Every time the number of frames specified has been played, 316 * a callback with event type EVENT_NEW_POS is called. 317 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 318 * callback. 319 * If the AudioTrack has been opened with no callback function associated, the operation will 320 * fail. 321 * 322 * Parameters: 323 * 324 * updatePeriod: position update notification period expressed in frames. 325 * 326 * Returned status (from utils/Errors.h) can be: 327 * - NO_ERROR: successful operation 328 * - INVALID_OPERATION: the AudioTrack has no callback installed. 329 */ 330 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 331 status_t getPositionUpdatePeriod(uint32_t *updatePeriod) const; 332 333 /* Sets playback head position within AudioTrack buffer. The new position is specified 334 * in number of frames. 335 * This method must be called with the AudioTrack in paused or stopped state. 336 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 337 * Therefore using this method makes sense only when playing a "static" audio buffer 338 * as opposed to streaming. 339 * The getPosition() method on the other hand returns the total number of frames played since 340 * playback start. 341 * 342 * Parameters: 343 * 344 * position: New playback head position within AudioTrack buffer. 345 * 346 * Returned status (from utils/Errors.h) can be: 347 * - NO_ERROR: successful operation 348 * - INVALID_OPERATION: the AudioTrack is not stopped. 349 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack 350 * buffer 351 */ 352 status_t setPosition(uint32_t position); 353 status_t getPosition(uint32_t *position); 354 355 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 356 * rewriting the buffer before restarting playback after a stop. 357 * This method must be called with the AudioTrack in paused or stopped state. 358 * 359 * Returned status (from utils/Errors.h) can be: 360 * - NO_ERROR: successful operation 361 * - INVALID_OPERATION: the AudioTrack is not stopped. 362 */ 363 status_t reload(); 364 365 /* Returns a handle on the audio output used by this AudioTrack. 366 * 367 * Parameters: 368 * none. 369 * 370 * Returned value: 371 * handle on audio hardware output 372 */ 373 audio_io_handle_t getOutput(); 374 375 /* Returns the unique session ID associated with this track. 376 * 377 * Parameters: 378 * none. 379 * 380 * Returned value: 381 * AudioTrack session ID. 382 */ 383 int getSessionId() const; 384 385 /* Attach track auxiliary output to specified effect. Use effectId = 0 386 * to detach track from effect. 387 * 388 * Parameters: 389 * 390 * effectId: effectId obtained from AudioEffect::id(). 391 * 392 * Returned status (from utils/Errors.h) can be: 393 * - NO_ERROR: successful operation 394 * - INVALID_OPERATION: the effect is not an auxiliary effect. 395 * - BAD_VALUE: The specified effect ID is invalid 396 */ 397 status_t attachAuxEffect(int effectId); 398 399 /* Obtains a buffer of "frameCount" frames. The buffer must be 400 * filled entirely, and then released with releaseBuffer(). 401 * If the track is stopped, obtainBuffer() returns 402 * STOPPED instead of NO_ERROR as long as there are buffers available, 403 * at which point NO_MORE_BUFFERS is returned. 404 * Buffers will be returned until the pool 405 * is exhausted, at which point obtainBuffer() will either block 406 * or return WOULD_BLOCK depending on the value of the "blocking" 407 * parameter. 408 * 409 * Interpretation of waitCount: 410 * +n limits wait time to n * WAIT_PERIOD_MS, 411 * -1 causes an (almost) infinite wait time, 412 * 0 non-blocking. 413 * 414 * Buffer fields 415 * On entry: 416 * frameCount number of frames requested 417 * After error return: 418 * frameCount 0 419 * size 0 420 * After successful return: 421 * frameCount actual number of frames available, <= number requested 422 * size actual number of bytes available 423 * raw pointer to the buffer 424 */ 425 426 enum { 427 NO_MORE_BUFFERS = 0x80000001, // same name in AudioFlinger.h, ok to be different value 428 STOPPED = 1 429 }; 430 431 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 432 433 /* Release a filled buffer of "frameCount" frames for AudioFlinger to process. */ 434 void releaseBuffer(Buffer* audioBuffer); 435 436 /* As a convenience we provide a write() interface to the audio buffer. 437 * This is implemented on top of obtainBuffer/releaseBuffer. For best 438 * performance use callbacks. Returns actual number of bytes written >= 0, 439 * or one of the following negative status codes: 440 * INVALID_OPERATION AudioTrack is configured for shared buffer mode 441 * BAD_VALUE size is invalid 442 * STOPPED AudioTrack was stopped during the write 443 * NO_MORE_BUFFERS when obtainBuffer() returns same 444 * or any other error code returned by IAudioTrack::start() or restoreTrack_l(). 445 */ 446 ssize_t write(const void* buffer, size_t size); 447 448 /* 449 * Dumps the state of an audio track. 450 */ 451 status_t dump(int fd, const Vector<String16>& args) const; 452 453protected: 454 /* copying audio tracks is not allowed */ 455 AudioTrack(const AudioTrack& other); 456 AudioTrack& operator = (const AudioTrack& other); 457 458 /* a small internal class to handle the callback */ 459 class AudioTrackThread : public Thread 460 { 461 public: 462 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 463 464 // Do not call Thread::requestExitAndWait() without first calling requestExit(). 465 // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough. 466 virtual void requestExit(); 467 468 void pause(); // suspend thread from execution at next loop boundary 469 void resume(); // allow thread to execute, if not requested to exit 470 471 private: 472 friend class AudioTrack; 473 virtual bool threadLoop(); 474 AudioTrack& mReceiver; 475 ~AudioTrackThread(); 476 Mutex mMyLock; // Thread::mLock is private 477 Condition mMyCond; // Thread::mThreadExitedCondition is private 478 bool mPaused; // whether thread is currently paused 479 }; 480 481 // body of AudioTrackThread::threadLoop() 482 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 483 484 // caller must hold lock on mLock for all _l methods 485 status_t createTrack_l(audio_stream_type_t streamType, 486 uint32_t sampleRate, 487 audio_format_t format, 488 audio_channel_mask_t channelMask, 489 int frameCount, 490 audio_output_flags_t flags, 491 const sp<IMemory>& sharedBuffer, 492 audio_io_handle_t output); 493 void flush_l(); 494 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 495 audio_io_handle_t getOutput_l(); 496 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 497 bool stopped_l() const { return !mActive; } 498 499 sp<IAudioTrack> mAudioTrack; 500 sp<IMemory> mCblkMemory; 501 sp<AudioTrackThread> mAudioTrackThread; 502 503 float mVolume[2]; 504 float mSendLevel; 505 uint32_t mFrameCount; 506 507 audio_track_cblk_t* mCblk; 508 audio_format_t mFormat; 509 audio_stream_type_t mStreamType; 510 uint8_t mChannelCount; 511 uint8_t mMuted; 512 uint8_t mReserved; 513 audio_channel_mask_t mChannelMask; 514 status_t mStatus; 515 uint32_t mLatency; 516 517 bool mActive; // protected by mLock 518 519 callback_t mCbf; // callback handler for events, or NULL 520 void* mUserData; // for client callback handler 521 522 // for notification APIs 523 uint32_t mNotificationFramesReq; // requested number of frames between each 524 // notification callback 525 uint32_t mNotificationFramesAct; // actual number of frames between each 526 // notification callback 527 sp<IMemory> mSharedBuffer; 528 int mLoopCount; 529 uint32_t mRemainingFrames; 530 uint32_t mMarkerPosition; // in frames 531 bool mMarkerReached; 532 uint32_t mNewPosition; // in frames 533 uint32_t mUpdatePeriod; // in frames 534 535 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 536 audio_output_flags_t mFlags; 537 int mSessionId; 538 int mAuxEffectId; 539 540 // When locking both mLock and mCblk->lock, must lock in this order to avoid deadlock: 541 // 1. mLock 542 // 2. mCblk->lock 543 // It is OK to lock only mCblk->lock. 544 mutable Mutex mLock; 545 546 status_t mRestoreStatus; 547 bool mIsTimed; 548 int mPreviousPriority; // before start() 549 SchedPolicy mPreviousSchedulingGroup; 550}; 551 552class TimedAudioTrack : public AudioTrack 553{ 554public: 555 TimedAudioTrack(); 556 557 /* allocate a shared memory buffer that can be passed to queueTimedBuffer */ 558 status_t allocateTimedBuffer(size_t size, sp<IMemory>* buffer); 559 560 /* queue a buffer obtained via allocateTimedBuffer for playback at the 561 given timestamp. PTS units are microseconds on the media time timeline. 562 The media time transform (set with setMediaTimeTransform) set by the 563 audio producer will handle converting from media time to local time 564 (perhaps going through the common time timeline in the case of 565 synchronized multiroom audio case) */ 566 status_t queueTimedBuffer(const sp<IMemory>& buffer, int64_t pts); 567 568 /* define a transform between media time and either common time or 569 local time */ 570 enum TargetTimeline {LOCAL_TIME, COMMON_TIME}; 571 status_t setMediaTimeTransform(const LinearTransform& xform, 572 TargetTimeline target); 573}; 574 575}; // namespace android 576 577#endif // ANDROID_AUDIOTRACK_H 578