AudioTrack.h revision 99e53b86eebb605b70dd7591b89bf61a9414ed0e
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 <utils/threads.h> 32 33namespace android { 34 35// ---------------------------------------------------------------------------- 36 37class audio_track_cblk_t; 38 39// ---------------------------------------------------------------------------- 40 41class AudioTrack : virtual public RefBase 42{ 43public: 44 enum channel_index { 45 MONO = 0, 46 LEFT = 0, 47 RIGHT = 1 48 }; 49 50 /* Events used by AudioTrack callback function (audio_track_cblk_t). 51 */ 52 enum event_type { 53 EVENT_MORE_DATA = 0, // Request to write more data to PCM buffer. 54 EVENT_UNDERRUN = 1, // PCM buffer underrun occured. 55 EVENT_LOOP_END = 2, // Sample loop end was reached; playback restarted from loop start if loop count was not 0. 56 EVENT_MARKER = 3, // Playback head is at the specified marker position (See setMarkerPosition()). 57 EVENT_NEW_POS = 4, // Playback head is at a new position (See setPositionUpdatePeriod()). 58 EVENT_BUFFER_END = 5 // Playback head is at the end of the buffer. 59 }; 60 61 /* Client should declare Buffer on the stack and pass address to obtainBuffer() 62 * and releaseBuffer(). See also callback_t for EVENT_MORE_DATA. 63 */ 64 65 class Buffer 66 { 67 public: 68 enum { 69 MUTE = 0x00000001 70 }; 71 uint32_t flags; // 0 or MUTE 72 audio_format_t format; // but AUDIO_FORMAT_PCM_8_BIT -> AUDIO_FORMAT_PCM_16_BIT 73 // accessed directly by WebKit ANP callback 74 int channelCount; // will be removed in the future, do not use 75 76 size_t frameCount; // number of sample frames corresponding to size; 77 // on input it is the number of frames desired, 78 // on output is the number of frames actually filled 79 80 size_t size; // input/output in byte units 81 union { 82 void* raw; 83 short* i16; // signed 16-bit 84 int8_t* i8; // unsigned 8-bit, offset by 0x80 85 }; 86 }; 87 88 89 /* As a convenience, if a callback is supplied, a handler thread 90 * is automatically created with the appropriate priority. This thread 91 * invokes the callback when a new buffer becomes available or various conditions occur. 92 * Parameters: 93 * 94 * event: type of event notified (see enum AudioTrack::event_type). 95 * user: Pointer to context for use by the callback receiver. 96 * info: Pointer to optional parameter according to event type: 97 * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write 98 * more bytes than indicated by 'size' field and update 'size' if fewer bytes are 99 * written. 100 * - EVENT_UNDERRUN: unused. 101 * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. 102 * - EVENT_MARKER: pointer to an uint32_t containing the marker position in frames. 103 * - EVENT_NEW_POS: pointer to an uint32_t containing the new position in frames. 104 * - EVENT_BUFFER_END: unused. 105 */ 106 107 typedef void (*callback_t)(int event, void* user, void *info); 108 109 /* Returns the minimum frame count required for the successful creation of 110 * an AudioTrack object. 111 * Returned status (from utils/Errors.h) can be: 112 * - NO_ERROR: successful operation 113 * - NO_INIT: audio server or audio hardware not initialized 114 */ 115 116 static status_t getMinFrameCount(int* frameCount, 117 audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 118 uint32_t sampleRate = 0); 119 120 /* Constructs an uninitialized AudioTrack. No connection with 121 * AudioFlinger takes place. 122 */ 123 AudioTrack(); 124 125 /* Creates an audio track and registers it with AudioFlinger. 126 * Once created, the track needs to be started before it can be used. 127 * Unspecified values are set to the audio hardware's current 128 * values. 129 * 130 * Parameters: 131 * 132 * streamType: Select the type of audio stream this track is attached to 133 * (e.g. AUDIO_STREAM_MUSIC). 134 * sampleRate: Track sampling rate in Hz. 135 * format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed 136 * 16 bits per sample). 137 * channelMask: Channel mask: see audio_channels_t. 138 * frameCount: Total size of track PCM buffer in frames. This defines the 139 * latency of the track. 140 * flags: Reserved for future use. 141 * cbf: Callback function. If not null, this function is called periodically 142 * to request 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 */ 148 149 AudioTrack( audio_stream_type_t streamType, 150 uint32_t sampleRate = 0, 151 audio_format_t format = AUDIO_FORMAT_DEFAULT, 152 int channelMask = 0, 153 int frameCount = 0, 154 uint32_t flags = 0, 155 callback_t cbf = NULL, 156 void* user = NULL, 157 int notificationFrames = 0, 158 int sessionId = 0); 159 160 // DEPRECATED 161 explicit AudioTrack( int streamType, 162 uint32_t sampleRate = 0, 163 int format = AUDIO_FORMAT_DEFAULT, 164 int channelMask = 0, 165 int frameCount = 0, 166 uint32_t flags = 0, 167 callback_t cbf = 0, 168 void* user = 0, 169 int notificationFrames = 0, 170 int sessionId = 0); 171 172 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 173 * the PCM data to be rendered by AudioTrack is passed in a shared memory buffer 174 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 175 * PCM data must be present in memory before the AudioTrack is started. 176 * The write() and flush() methods are not supported in this case. 177 * It is recommended to pass a callback function to be notified of playback end by an 178 * EVENT_UNDERRUN event. 179 */ 180 181 AudioTrack( audio_stream_type_t streamType, 182 uint32_t sampleRate = 0, 183 audio_format_t format = AUDIO_FORMAT_DEFAULT, 184 int channelMask = 0, 185 const sp<IMemory>& sharedBuffer = 0, 186 uint32_t flags = 0, 187 callback_t cbf = NULL, 188 void* user = NULL, 189 int notificationFrames = 0, 190 int sessionId = 0); 191 192 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 193 * Also destroys all resources associated with the AudioTrack. 194 */ 195 ~AudioTrack(); 196 197 198 /* Initialize an uninitialized AudioTrack. 199 * Returned status (from utils/Errors.h) can be: 200 * - NO_ERROR: successful initialization 201 * - INVALID_OPERATION: AudioTrack is already initialized 202 * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) 203 * - NO_INIT: audio server or audio hardware not initialized 204 * */ 205 status_t set(audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 206 uint32_t sampleRate = 0, 207 audio_format_t format = AUDIO_FORMAT_DEFAULT, 208 int channelMask = 0, 209 int frameCount = 0, 210 uint32_t flags = 0, 211 callback_t cbf = NULL, 212 void* user = NULL, 213 int notificationFrames = 0, 214 const sp<IMemory>& sharedBuffer = 0, 215 bool threadCanCallJava = false, 216 int sessionId = 0); 217 218 219 /* Result of constructing the AudioTrack. This must be checked 220 * before using any AudioTrack API (except for set()), because using 221 * an uninitialized AudioTrack produces undefined results. 222 * See set() method above for possible return codes. 223 */ 224 status_t initCheck() const; 225 226 /* Returns this track's estimated latency in milliseconds. 227 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 228 * and audio hardware driver. 229 */ 230 uint32_t latency() const; 231 232 /* getters, see constructors and set() */ 233 234 audio_stream_type_t streamType() const; 235 audio_format_t format() const; 236 int channelCount() const; 237 uint32_t frameCount() const; 238 239 /* Return channelCount * (bit depth per channel / 8). 240 * channelCount is determined from channelMask, and bit depth comes from format. 241 */ 242 size_t frameSize() const; 243 244 sp<IMemory>& sharedBuffer(); 245 246 247 /* After it's created the track is not active. Call start() to 248 * make it active. If set, the callback will start being called. 249 */ 250 void start(); 251 252 /* Stop a track. If set, the callback will cease being called and 253 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 254 * and will fill up buffers until the pool is exhausted. 255 */ 256 void stop(); 257 bool stopped() const; 258 259 /* Flush a stopped track. All pending buffers are discarded. 260 * This function has no effect if the track is not stopped. 261 */ 262 void flush(); 263 264 /* Pause a track. If set, the callback will cease being called and 265 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 266 * and will fill up buffers until the pool is exhausted. 267 */ 268 void pause(); 269 270 /* Mute or unmute this track. 271 * While muted, the callback, if set, is still called. 272 */ 273 void mute(bool); 274 bool muted() const; 275 276 /* Set volume for this track, mostly used for games' sound effects 277 * left and right volumes. Levels must be >= 0.0 and <= 1.0. 278 */ 279 status_t setVolume(float left, float right); 280 void getVolume(float* left, float* right) const; 281 282 /* Set the send level for this track. An auxiliary effect should be attached 283 * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0. 284 */ 285 status_t setAuxEffectSendLevel(float level); 286 void getAuxEffectSendLevel(float* level) const; 287 288 /* Set sample rate for this track, mostly used for games' sound effects 289 */ 290 status_t setSampleRate(int sampleRate); 291 uint32_t getSampleRate() const; 292 293 /* Enables looping and sets the start and end points of looping. 294 * 295 * Parameters: 296 * 297 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 298 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 299 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any 300 * pending or active loop. loopCount = -1 means infinite looping. 301 * 302 * For proper operation the following condition must be respected: 303 * (loopEnd-loopStart) <= framecount() 304 */ 305 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 306 status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount) const; 307 308 /* Sets marker position. When playback reaches the number of frames specified, a callback with 309 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 310 * notification callback. 311 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 312 * 313 * Parameters: 314 * 315 * marker: marker position expressed in frames. 316 * 317 * Returned status (from utils/Errors.h) can be: 318 * - NO_ERROR: successful operation 319 * - INVALID_OPERATION: the AudioTrack has no callback installed. 320 */ 321 status_t setMarkerPosition(uint32_t marker); 322 status_t getMarkerPosition(uint32_t *marker) const; 323 324 325 /* Sets position update period. Every time the number of frames specified has been played, 326 * a callback with event type EVENT_NEW_POS is called. 327 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 328 * callback. 329 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 330 * 331 * Parameters: 332 * 333 * updatePeriod: position update notification period expressed in frames. 334 * 335 * Returned status (from utils/Errors.h) can be: 336 * - NO_ERROR: successful operation 337 * - INVALID_OPERATION: the AudioTrack has no callback installed. 338 */ 339 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 340 status_t getPositionUpdatePeriod(uint32_t *updatePeriod) const; 341 342 /* Sets playback head position within AudioTrack buffer. The new position is specified 343 * in number of frames. 344 * This method must be called with the AudioTrack in paused or stopped state. 345 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 346 * Therefore using this method makes sense only when playing a "static" audio buffer 347 * as opposed to streaming. 348 * The getPosition() method on the other hand returns the total number of frames played since 349 * playback start. 350 * 351 * Parameters: 352 * 353 * position: New playback head position within AudioTrack buffer. 354 * 355 * Returned status (from utils/Errors.h) can be: 356 * - NO_ERROR: successful operation 357 * - INVALID_OPERATION: the AudioTrack is not stopped. 358 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack 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 (buffercount()) 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 450private: 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 private: 461 friend class AudioTrack; 462 virtual bool threadLoop(); 463 virtual status_t readyToRun(); 464 virtual void onFirstRef(); 465 AudioTrack& mReceiver; 466 }; 467 468 // body of AudioTrackThread::threadLoop() 469 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 470 status_t createTrack_l(audio_stream_type_t streamType, 471 uint32_t sampleRate, 472 audio_format_t format, 473 uint32_t channelMask, 474 int frameCount, 475 uint32_t flags, 476 const sp<IMemory>& sharedBuffer, 477 audio_io_handle_t output, 478 bool enforceFrameCount); 479 void flush_l(); 480 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 481 audio_io_handle_t getOutput_l(); 482 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 483 bool stopped_l() const { return !mActive; } 484 485 sp<IAudioTrack> mAudioTrack; 486 sp<IMemory> mCblkMemory; 487 sp<AudioTrackThread> mAudioTrackThread; 488 489 float mVolume[2]; 490 float mSendLevel; 491 uint32_t mFrameCount; 492 493 audio_track_cblk_t* mCblk; 494 audio_format_t mFormat; 495 audio_stream_type_t mStreamType; 496 uint8_t mChannelCount; 497 uint8_t mMuted; 498 uint8_t mReserved; 499 uint32_t mChannelMask; 500 status_t mStatus; 501 uint32_t mLatency; 502 503 bool mActive; // protected by mLock 504 505 callback_t mCbf; // callback handler for events, or NULL 506 void* mUserData; 507 uint32_t mNotificationFramesReq; // requested number of frames between each notification callback 508 uint32_t mNotificationFramesAct; // actual number of frames between each notification callback 509 sp<IMemory> mSharedBuffer; 510 int mLoopCount; 511 uint32_t mRemainingFrames; 512 uint32_t mMarkerPosition; 513 bool mMarkerReached; 514 uint32_t mNewPosition; 515 uint32_t mUpdatePeriod; 516 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 517 uint32_t mFlags; 518 int mSessionId; 519 int mAuxEffectId; 520 mutable Mutex mLock; 521 status_t mRestoreStatus; 522 int mPreviousPriority; // before start() 523 int mPreviousSchedulingGroup; 524}; 525 526 527}; // namespace android 528 529#endif // ANDROID_AUDIOTRACK_H 530