AudioTrack.h revision 847d05dc8fa144dcf8f4f435d6a6ac1727f00937
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 enum { 74 MUTE = 0x00000001 75 }; 76 uint32_t flags; // 0 or MUTE 77 audio_format_t format; // but AUDIO_FORMAT_PCM_8_BIT -> AUDIO_FORMAT_PCM_16_BIT 78 // accessed directly by WebKit ANP callback 79 int channelCount; // will be removed in the future, do not use 80 81 size_t frameCount; // number of sample frames corresponding to size; 82 // on input it is the number of frames desired, 83 // on output is the number of frames actually filled 84 85 size_t size; // input/output in byte units 86 union { 87 void* raw; 88 short* i16; // signed 16-bit 89 int8_t* i8; // unsigned 8-bit, offset by 0x80 90 }; 91 }; 92 93 94 /* As a convenience, if a callback is supplied, a handler thread 95 * is automatically created with the appropriate priority. This thread 96 * invokes the callback when a new buffer becomes available or various conditions occur. 97 * Parameters: 98 * 99 * event: type of event notified (see enum AudioTrack::event_type). 100 * user: Pointer to context for use by the callback receiver. 101 * info: Pointer to optional parameter according to event type: 102 * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write 103 * more bytes than indicated by 'size' field and update 'size' if fewer bytes are 104 * written. 105 * - EVENT_UNDERRUN: unused. 106 * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. 107 * - EVENT_MARKER: pointer to an uint32_t containing the marker position in frames. 108 * - EVENT_NEW_POS: pointer to an uint32_t containing the new position in frames. 109 * - EVENT_BUFFER_END: unused. 110 */ 111 112 typedef void (*callback_t)(int event, void* user, void *info); 113 114 /* Returns the minimum frame count required for the successful creation of 115 * an AudioTrack object. 116 * Returned status (from utils/Errors.h) can be: 117 * - NO_ERROR: successful operation 118 * - NO_INIT: audio server or audio hardware not initialized 119 */ 120 121 static status_t getMinFrameCount(int* frameCount, 122 audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 123 uint32_t sampleRate = 0); 124 125 /* Constructs an uninitialized AudioTrack. No connection with 126 * AudioFlinger takes place. 127 */ 128 AudioTrack(); 129 130 /* Creates an AudioTrack object and registers it with AudioFlinger. 131 * Once created, the track needs to be started before it can be used. 132 * Unspecified values are set to the audio hardware's current 133 * values. 134 * 135 * Parameters: 136 * 137 * streamType: Select the type of audio stream this track is attached to 138 * (e.g. AUDIO_STREAM_MUSIC). 139 * sampleRate: Track sampling rate in Hz. 140 * format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed 141 * 16 bits per sample). 142 * channelMask: Channel mask. 143 * frameCount: Minimum size of track PCM buffer in frames. This defines the 144 * application's contribution to the 145 * latency of the track. The actual size selected by the AudioTrack could be 146 * larger if the requested size is not compatible with current audio HAL 147 * latency. Zero means to use a default value. 148 * flags: See comments on audio_output_flags_t in <system/audio.h>. 149 * cbf: Callback function. If not null, this function is called periodically 150 * to provide new PCM data. 151 * user: Context for use by the callback receiver. 152 * notificationFrames: The callback function is called each time notificationFrames PCM 153 * frames have been consumed from track input buffer. 154 * sessionId: Specific session ID, or zero to use default. 155 * threadCanCallJava: Whether callbacks are made from an attached thread and thus can call JNI. 156 * If not present in parameter list, then fixed at false. 157 */ 158 159 AudioTrack( audio_stream_type_t streamType, 160 uint32_t sampleRate = 0, 161 audio_format_t format = AUDIO_FORMAT_DEFAULT, 162 audio_channel_mask_t channelMask = 0, 163 int frameCount = 0, 164 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 165 callback_t cbf = NULL, 166 void* user = NULL, 167 int notificationFrames = 0, 168 int sessionId = 0); 169 170 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 171 * the PCM data to be rendered by AudioTrack is passed in a shared memory buffer 172 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 173 * PCM data must be present in memory before the AudioTrack is started. 174 * The write() and flush() methods are not supported in this case. 175 * It is recommended to pass a callback function to be notified of playback end by an 176 * EVENT_UNDERRUN event. 177 */ 178 179 AudioTrack( audio_stream_type_t streamType, 180 uint32_t sampleRate = 0, 181 audio_format_t format = AUDIO_FORMAT_DEFAULT, 182 audio_channel_mask_t channelMask = 0, 183 const sp<IMemory>& sharedBuffer = 0, 184 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 185 callback_t cbf = NULL, 186 void* user = NULL, 187 int notificationFrames = 0, 188 int sessionId = 0); 189 190 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 191 * Also destroys all resources associated with the AudioTrack. 192 */ 193 ~AudioTrack(); 194 195 196 /* Initialize an uninitialized AudioTrack. 197 * Returned status (from utils/Errors.h) can be: 198 * - NO_ERROR: successful initialization 199 * - INVALID_OPERATION: AudioTrack is already initialized 200 * - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...) 201 * - NO_INIT: audio server or audio hardware not initialized 202 */ 203 status_t set(audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 204 uint32_t sampleRate = 0, 205 audio_format_t format = AUDIO_FORMAT_DEFAULT, 206 audio_channel_mask_t channelMask = 0, 207 int frameCount = 0, 208 audio_output_flags_t flags = AUDIO_OUTPUT_FLAG_NONE, 209 callback_t cbf = NULL, 210 void* user = NULL, 211 int notificationFrames = 0, 212 const sp<IMemory>& sharedBuffer = 0, 213 bool threadCanCallJava = false, 214 int sessionId = 0); 215 216 217 /* Result of constructing the AudioTrack. This must be checked 218 * before using any AudioTrack API (except for set()), because using 219 * an uninitialized AudioTrack produces undefined results. 220 * See set() method above for possible return codes. 221 */ 222 status_t initCheck() const; 223 224 /* Returns this track's estimated latency in milliseconds. 225 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 226 * and audio hardware driver. 227 */ 228 uint32_t latency() const; 229 230 /* getters, see constructors and set() */ 231 232 audio_stream_type_t streamType() const; 233 audio_format_t format() const; 234 int channelCount() const; 235 uint32_t frameCount() const; 236 237 /* Return channelCount * (bit depth per channel / 8). 238 * channelCount is determined from channelMask, and bit depth comes from format. 239 */ 240 size_t frameSize() const; 241 242 sp<IMemory>& sharedBuffer(); 243 244 245 /* After it's created the track is not active. Call start() to 246 * make it active. If set, the callback will start being called. 247 */ 248 void start(); 249 250 /* Stop a track. If set, the callback will cease being called and 251 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 252 * and will fill up buffers until the pool is exhausted. 253 */ 254 void stop(); 255 bool stopped() const; 256 257 /* Flush a stopped track. All pending buffers are discarded. 258 * This function has no effect if the track is not stopped. 259 */ 260 void flush(); 261 262 /* Pause a track. If set, the callback will cease being called and 263 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 264 * and will fill up buffers until the pool is exhausted. 265 */ 266 void pause(); 267 268 /* Mute or unmute this track. 269 * While muted, the callback, if set, is still called. 270 */ 271 void mute(bool); 272 bool muted() const; 273 274 /* Set volume for this track, mostly used for games' sound effects 275 * left and right volumes. Levels must be >= 0.0 and <= 1.0. 276 */ 277 status_t setVolume(float left, float right); 278 void getVolume(float* left, float* right) const; 279 280 /* Set the send level for this track. An auxiliary effect should be attached 281 * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0. 282 */ 283 status_t setAuxEffectSendLevel(float level); 284 void getAuxEffectSendLevel(float* level) const; 285 286 /* Set sample rate for this track in Hz, mostly used for games' sound effects 287 */ 288 status_t setSampleRate(int sampleRate); 289 uint32_t getSampleRate() const; 290 291 /* Enables looping and sets the start and end points of looping. 292 * 293 * Parameters: 294 * 295 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 296 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 297 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any 298 * pending or active loop. loopCount = -1 means infinite looping. 299 * 300 * For proper operation the following condition must be respected: 301 * (loopEnd-loopStart) <= framecount() 302 */ 303 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 304 305 /* Sets marker position. When playback reaches the number of frames specified, a callback with 306 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 307 * notification callback. 308 * If the AudioTrack has been opened with no callback function associated, the operation will 309 * fail. 310 * 311 * Parameters: 312 * 313 * marker: marker position expressed in frames. 314 * 315 * Returned status (from utils/Errors.h) can be: 316 * - NO_ERROR: successful operation 317 * - INVALID_OPERATION: the AudioTrack has no callback installed. 318 */ 319 status_t setMarkerPosition(uint32_t marker); 320 status_t getMarkerPosition(uint32_t *marker) const; 321 322 323 /* Sets position update period. Every time the number of frames specified has been played, 324 * a callback with event type EVENT_NEW_POS is called. 325 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 326 * callback. 327 * If the AudioTrack has been opened with no callback function associated, the operation will 328 * fail. 329 * 330 * Parameters: 331 * 332 * updatePeriod: position update notification period expressed in frames. 333 * 334 * Returned status (from utils/Errors.h) can be: 335 * - NO_ERROR: successful operation 336 * - INVALID_OPERATION: the AudioTrack has no callback installed. 337 */ 338 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 339 status_t getPositionUpdatePeriod(uint32_t *updatePeriod) const; 340 341 /* Sets playback head position within AudioTrack buffer. The new position is specified 342 * in number of frames. 343 * This method must be called with the AudioTrack in paused or stopped state. 344 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 345 * Therefore using this method makes sense only when playing a "static" audio buffer 346 * as opposed to streaming. 347 * The getPosition() method on the other hand returns the total number of frames played since 348 * playback start. 349 * 350 * Parameters: 351 * 352 * position: New playback head position within AudioTrack buffer. 353 * 354 * Returned status (from utils/Errors.h) can be: 355 * - NO_ERROR: successful operation 356 * - INVALID_OPERATION: the AudioTrack is not stopped. 357 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack 358 * buffer 359 */ 360 status_t setPosition(uint32_t position); 361 status_t getPosition(uint32_t *position); 362 363 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 364 * rewriting the buffer before restarting playback after a stop. 365 * This method must be called with the AudioTrack in paused or stopped state. 366 * 367 * Returned status (from utils/Errors.h) can be: 368 * - NO_ERROR: successful operation 369 * - INVALID_OPERATION: the AudioTrack is not stopped. 370 */ 371 status_t reload(); 372 373 /* Returns a handle on the audio output used by this AudioTrack. 374 * 375 * Parameters: 376 * none. 377 * 378 * Returned value: 379 * handle on audio hardware output 380 */ 381 audio_io_handle_t getOutput(); 382 383 /* Returns the unique session ID associated with this track. 384 * 385 * Parameters: 386 * none. 387 * 388 * Returned value: 389 * AudioTrack session ID. 390 */ 391 int getSessionId() const; 392 393 /* Attach track auxiliary output to specified effect. Use effectId = 0 394 * to detach track from effect. 395 * 396 * Parameters: 397 * 398 * effectId: effectId obtained from AudioEffect::id(). 399 * 400 * Returned status (from utils/Errors.h) can be: 401 * - NO_ERROR: successful operation 402 * - INVALID_OPERATION: the effect is not an auxiliary effect. 403 * - BAD_VALUE: The specified effect ID is invalid 404 */ 405 status_t attachAuxEffect(int effectId); 406 407 /* Obtains a buffer of "frameCount" frames. The buffer must be 408 * filled entirely, and then released with releaseBuffer(). 409 * If the track is stopped, obtainBuffer() returns 410 * STOPPED instead of NO_ERROR as long as there are buffers available, 411 * at which point NO_MORE_BUFFERS is returned. 412 * Buffers will be returned until the pool 413 * is exhausted, at which point obtainBuffer() will either block 414 * or return WOULD_BLOCK depending on the value of the "blocking" 415 * parameter. 416 * 417 * Interpretation of waitCount: 418 * +n limits wait time to n * WAIT_PERIOD_MS, 419 * -1 causes an (almost) infinite wait time, 420 * 0 non-blocking. 421 */ 422 423 enum { 424 NO_MORE_BUFFERS = 0x80000001, // same name in AudioFlinger.h, ok to be different value 425 STOPPED = 1 426 }; 427 428 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 429 430 /* Release a filled buffer of "frameCount" frames for AudioFlinger to process. */ 431 void releaseBuffer(Buffer* audioBuffer); 432 433 /* As a convenience we provide a write() interface to the audio buffer. 434 * This is implemented on top of obtainBuffer/releaseBuffer. For best 435 * performance use callbacks. Returns actual number of bytes written >= 0, 436 * or one of the following negative status codes: 437 * INVALID_OPERATION AudioTrack is configured for shared buffer mode 438 * BAD_VALUE size is invalid 439 * STOPPED AudioTrack was stopped during the write 440 * NO_MORE_BUFFERS when obtainBuffer() returns same 441 * or any other error code returned by IAudioTrack::start() or restoreTrack_l(). 442 */ 443 ssize_t write(const void* buffer, size_t size); 444 445 /* 446 * Dumps the state of an audio track. 447 */ 448 status_t dump(int fd, const Vector<String16>& args) const; 449 450protected: 451 /* copying audio tracks is not allowed */ 452 AudioTrack(const AudioTrack& other); 453 AudioTrack& operator = (const AudioTrack& other); 454 455 /* a small internal class to handle the callback */ 456 class AudioTrackThread : public Thread 457 { 458 public: 459 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 460 461 // Do not call Thread::requestExitAndWait() without first calling requestExit(). 462 // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough. 463 virtual void requestExit(); 464 465 void pause(); // suspend thread from execution at next loop boundary 466 void resume(); // allow thread to execute, if not requested to exit 467 468 private: 469 friend class AudioTrack; 470 virtual bool threadLoop(); 471 AudioTrack& mReceiver; 472 ~AudioTrackThread(); 473 Mutex mMyLock; // Thread::mLock is private 474 Condition mMyCond; // Thread::mThreadExitedCondition is private 475 bool mPaused; // whether thread is currently paused 476 }; 477 478 // body of AudioTrackThread::threadLoop() 479 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 480 481 status_t createTrack_l(audio_stream_type_t streamType, 482 uint32_t sampleRate, 483 audio_format_t format, 484 audio_channel_mask_t channelMask, 485 int frameCount, 486 audio_output_flags_t flags, 487 const sp<IMemory>& sharedBuffer, 488 audio_io_handle_t output); 489 void flush_l(); 490 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 491 audio_io_handle_t getOutput_l(); 492 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 493 bool stopped_l() const { return !mActive; } 494 495 sp<IAudioTrack> mAudioTrack; 496 sp<IMemory> mCblkMemory; 497 sp<AudioTrackThread> mAudioTrackThread; 498 499 float mVolume[2]; 500 float mSendLevel; 501 uint32_t mFrameCount; 502 503 audio_track_cblk_t* mCblk; 504 audio_format_t mFormat; 505 audio_stream_type_t mStreamType; 506 uint8_t mChannelCount; 507 uint8_t mMuted; 508 uint8_t mReserved; 509 audio_channel_mask_t mChannelMask; 510 status_t mStatus; 511 uint32_t mLatency; 512 513 bool mActive; // protected by mLock 514 515 callback_t mCbf; // callback handler for events, or NULL 516 void* mUserData; // for client callback handler 517 518 // for notification APIs 519 uint32_t mNotificationFramesReq; // requested number of frames between each 520 // notification callback 521 uint32_t mNotificationFramesAct; // actual number of frames between each 522 // notification callback 523 sp<IMemory> mSharedBuffer; 524 int mLoopCount; 525 uint32_t mRemainingFrames; 526 uint32_t mMarkerPosition; // in frames 527 bool mMarkerReached; 528 uint32_t mNewPosition; // in frames 529 uint32_t mUpdatePeriod; // in frames 530 531 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 532 audio_output_flags_t mFlags; 533 int mSessionId; 534 int mAuxEffectId; 535 mutable Mutex mLock; 536 status_t mRestoreStatus; 537 bool mIsTimed; 538 int mPreviousPriority; // before start() 539 SchedPolicy mPreviousSchedulingGroup; 540}; 541 542class TimedAudioTrack : public AudioTrack 543{ 544public: 545 TimedAudioTrack(); 546 547 /* allocate a shared memory buffer that can be passed to queueTimedBuffer */ 548 status_t allocateTimedBuffer(size_t size, sp<IMemory>* buffer); 549 550 /* queue a buffer obtained via allocateTimedBuffer for playback at the 551 given timestamp. PTS units are microseconds on the media time timeline. 552 The media time transform (set with setMediaTimeTransform) set by the 553 audio producer will handle converting from media time to local time 554 (perhaps going through the common time timeline in the case of 555 synchronized multiroom audio case) */ 556 status_t queueTimedBuffer(const sp<IMemory>& buffer, int64_t pts); 557 558 /* define a transform between media time and either common time or 559 local time */ 560 enum TargetTimeline {LOCAL_TIME, COMMON_TIME}; 561 status_t setMediaTimeTransform(const LinearTransform& xform, 562 TargetTimeline target); 563}; 564 565}; // namespace android 566 567#endif // ANDROID_AUDIOTRACK_H 568