AudioTrack.h revision 1703cdfee717b1b312bf8979816a9e2f16a82e5d
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 33 34namespace android { 35 36// ---------------------------------------------------------------------------- 37 38class audio_track_cblk_t; 39 40// ---------------------------------------------------------------------------- 41 42class AudioTrack 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 */ 53 enum event_type { 54 EVENT_MORE_DATA = 0, // Request to write more data to PCM buffer. 55 EVENT_UNDERRUN = 1, // PCM buffer underrun occured. 56 EVENT_LOOP_END = 2, // Sample loop end was reached; playback restarted from loop start if loop count was not 0. 57 EVENT_MARKER = 3, // Playback head is at the specified marker position (See setMarkerPosition()). 58 EVENT_NEW_POS = 4, // Playback head is at a new position (See setPositionUpdatePeriod()). 59 EVENT_BUFFER_END = 5 // Playback head is at the end of the buffer. 60 }; 61 62 /* Create Buffer on the stack and pass it to obtainBuffer() 63 * and releaseBuffer(). 64 */ 65 66 class Buffer 67 { 68 public: 69 enum { 70 MUTE = 0x00000001 71 }; 72 uint32_t flags; 73 int channelCount; 74 int format; 75 size_t frameCount; 76 size_t size; 77 union { 78 void* raw; 79 short* i16; 80 int8_t* i8; 81 }; 82 }; 83 84 85 /* As a convenience, if a callback is supplied, a handler thread 86 * is automatically created with the appropriate priority. This thread 87 * invokes the callback when a new buffer becomes availlable or an underrun condition occurs. 88 * Parameters: 89 * 90 * event: type of event notified (see enum AudioTrack::event_type). 91 * user: Pointer to context for use by the callback receiver. 92 * info: Pointer to optional parameter according to event type: 93 * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write 94 * more bytes than indicated by 'size' field and update 'size' if less bytes are 95 * written. 96 * - EVENT_UNDERRUN: unused. 97 * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. 98 * - EVENT_MARKER: pointer to an uin32_t containing the marker position in frames. 99 * - EVENT_NEW_POS: pointer to an uin32_t containing the new position in frames. 100 * - EVENT_BUFFER_END: unused. 101 */ 102 103 typedef void (*callback_t)(int event, void* user, void *info); 104 105 /* Returns the minimum frame count required for the successful creation of 106 * an AudioTrack object. 107 * Returned status (from utils/Errors.h) can be: 108 * - NO_ERROR: successful operation 109 * - NO_INIT: audio server or audio hardware not initialized 110 */ 111 112 static status_t getMinFrameCount(int* frameCount, 113 int streamType =-1, 114 uint32_t sampleRate = 0); 115 116 /* Constructs an uninitialized AudioTrack. No connection with 117 * AudioFlinger takes place. 118 */ 119 AudioTrack(); 120 121 /* Creates an audio track and registers it with AudioFlinger. 122 * Once created, the track needs to be started before it can be used. 123 * Unspecified values are set to the audio hardware's current 124 * values. 125 * 126 * Parameters: 127 * 128 * streamType: Select the type of audio stream this track is attached to 129 * (e.g. AudioSystem::MUSIC). 130 * sampleRate: Track sampling rate in Hz. 131 * format: Audio format (e.g AudioSystem::PCM_16_BIT for signed 132 * 16 bits per sample). 133 * channels: Channel mask: see AudioSystem::audio_channels. 134 * frameCount: Total size of track PCM buffer in frames. This defines the 135 * latency of the track. 136 * flags: Reserved for future use. 137 * cbf: Callback function. If not null, this function is called periodically 138 * to request new PCM data. 139 * notificationFrames: The callback function is called each time notificationFrames PCM 140 * frames have been comsumed from track input buffer. 141 * user Context for use by the callback receiver. 142 */ 143 144 AudioTrack( int streamType, 145 uint32_t sampleRate = 0, 146 int format = 0, 147 int channels = 0, 148 int frameCount = 0, 149 uint32_t flags = 0, 150 callback_t cbf = 0, 151 void* user = 0, 152 int notificationFrames = 0, 153 int sessionId = 0); 154 155 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 156 * The PCM data to be rendered by AudioTrack is passed in a shared memory buffer 157 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 158 * PCM data must be present into memory before the AudioTrack is started. 159 * The Write() and Flush() methods are not supported in this case. 160 * It is recommented to pass a callback function to be notified of playback end by an 161 * EVENT_UNDERRUN event. 162 */ 163 164 AudioTrack( int streamType, 165 uint32_t sampleRate = 0, 166 int format = 0, 167 int channels = 0, 168 const sp<IMemory>& sharedBuffer = 0, 169 uint32_t flags = 0, 170 callback_t cbf = 0, 171 void* user = 0, 172 int notificationFrames = 0, 173 int sessionId = 0); 174 175 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 176 * Also destroys all resources assotiated with the AudioTrack. 177 */ 178 ~AudioTrack(); 179 180 181 /* Initialize an uninitialized AudioTrack. 182 * Returned status (from utils/Errors.h) can be: 183 * - NO_ERROR: successful intialization 184 * - INVALID_OPERATION: AudioTrack is already intitialized 185 * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) 186 * - NO_INIT: audio server or audio hardware not initialized 187 * */ 188 status_t set(int streamType =-1, 189 uint32_t sampleRate = 0, 190 int format = 0, 191 int channels = 0, 192 int frameCount = 0, 193 uint32_t flags = 0, 194 callback_t cbf = 0, 195 void* user = 0, 196 int notificationFrames = 0, 197 const sp<IMemory>& sharedBuffer = 0, 198 bool threadCanCallJava = false, 199 int sessionId = 0); 200 201 202 /* Result of constructing the AudioTrack. This must be checked 203 * before using any AudioTrack API (except for set()), using 204 * an uninitialized AudioTrack produces undefined results. 205 * See set() method above for possible return codes. 206 */ 207 status_t initCheck() const; 208 209 /* Returns this track's latency in milliseconds. 210 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 211 * and audio hardware driver. 212 */ 213 uint32_t latency() const; 214 215 /* getters, see constructor */ 216 217 int streamType() const; 218 int format() const; 219 int channelCount() const; 220 uint32_t frameCount() const; 221 int frameSize() const; 222 sp<IMemory>& sharedBuffer(); 223 224 225 /* After it's created the track is not active. Call start() to 226 * make it active. If set, the callback will start being called. 227 */ 228 void start(); 229 230 /* Stop a track. If set, the callback will cease being called and 231 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 232 * and will fill up buffers until the pool is exhausted. 233 */ 234 void stop(); 235 bool stopped() const; 236 237 /* flush a stopped track. All pending buffers are discarded. 238 * This function has no effect if the track is not stoped. 239 */ 240 void flush(); 241 242 /* Pause 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 pause(); 247 248 /* mute or unmutes this track. 249 * While mutted, the callback, if set, is still called. 250 */ 251 void mute(bool); 252 bool muted() const; 253 254 255 /* set volume for this track, mostly used for games' sound effects 256 * left and right volumes. Levels must be <= 1.0. 257 */ 258 status_t setVolume(float left, float right); 259 void getVolume(float* left, float* right); 260 261 /* set the send level for this track. An auxiliary effect should be attached 262 * to the track with attachEffect(). Level must be <= 1.0. 263 */ 264 status_t setAuxEffectSendLevel(float level); 265 void getAuxEffectSendLevel(float* level); 266 267 /* set sample rate for this track, mostly used for games' sound effects 268 */ 269 status_t setSampleRate(int sampleRate); 270 uint32_t getSampleRate(); 271 272 /* Enables looping and sets the start and end points of looping. 273 * 274 * Parameters: 275 * 276 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 277 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 278 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any pending or 279 * active loop. loopCount = -1 means infinite looping. 280 * 281 * For proper operation the following condition must be respected: 282 * (loopEnd-loopStart) <= framecount() 283 */ 284 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 285 status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount); 286 287 288 /* Sets marker position. When playback reaches the number of frames specified, a callback with event 289 * type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker notification 290 * callback. 291 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 292 * 293 * Parameters: 294 * 295 * marker: marker position expressed in frames. 296 * 297 * Returned status (from utils/Errors.h) can be: 298 * - NO_ERROR: successful operation 299 * - INVALID_OPERATION: the AudioTrack has no callback installed. 300 */ 301 status_t setMarkerPosition(uint32_t marker); 302 status_t getMarkerPosition(uint32_t *marker); 303 304 305 /* Sets position update period. Every time the number of frames specified has been played, 306 * a callback with event type EVENT_NEW_POS is called. 307 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 308 * callback. 309 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 310 * 311 * Parameters: 312 * 313 * updatePeriod: position update notification period 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 setPositionUpdatePeriod(uint32_t updatePeriod); 320 status_t getPositionUpdatePeriod(uint32_t *updatePeriod); 321 322 323 /* Sets playback head position within AudioTrack buffer. The new position is specified 324 * in number of frames. 325 * This method must be called with the AudioTrack in paused or stopped state. 326 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 327 * Therefore using this method makes sense only when playing a "static" audio buffer 328 * as opposed to streaming. 329 * The getPosition() method on the other hand returns the total number of frames played since 330 * playback start. 331 * 332 * Parameters: 333 * 334 * position: New playback head position within AudioTrack buffer. 335 * 336 * Returned status (from utils/Errors.h) can be: 337 * - NO_ERROR: successful operation 338 * - INVALID_OPERATION: the AudioTrack is not stopped. 339 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 340 */ 341 status_t setPosition(uint32_t position); 342 status_t getPosition(uint32_t *position); 343 344 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 345 * rewriting the buffer before restarting playback after a stop. 346 * This method must be called with the AudioTrack in paused or stopped state. 347 * 348 * Returned status (from utils/Errors.h) can be: 349 * - NO_ERROR: successful operation 350 * - INVALID_OPERATION: the AudioTrack is not stopped. 351 */ 352 status_t reload(); 353 354 /* returns a handle on the audio output used by this AudioTrack. 355 * 356 * Parameters: 357 * none. 358 * 359 * Returned value: 360 * handle on audio hardware output 361 */ 362 audio_io_handle_t getOutput(); 363 364 /* returns the unique ID associated to this track. 365 * 366 * Parameters: 367 * none. 368 * 369 * Returned value: 370 * AudioTrack ID. 371 */ 372 int getSessionId(); 373 374 375 /* Attach track auxiliary output to specified effect. Used effectId = 0 376 * to detach track from effect. 377 * 378 * Parameters: 379 * 380 * effectId: effectId obtained from AudioEffect::id(). 381 * 382 * Returned status (from utils/Errors.h) can be: 383 * - NO_ERROR: successful operation 384 * - INVALID_OPERATION: the effect is not an auxiliary effect. 385 * - BAD_VALUE: The specified effect ID is invalid 386 */ 387 status_t attachAuxEffect(int effectId); 388 389 /* obtains a buffer of "frameCount" frames. The buffer must be 390 * filled entirely. If the track is stopped, obtainBuffer() returns 391 * STOPPED instead of NO_ERROR as long as there are buffers availlable, 392 * at which point NO_MORE_BUFFERS is returned. 393 * Buffers will be returned until the pool (buffercount()) 394 * is exhausted, at which point obtainBuffer() will either block 395 * or return WOULD_BLOCK depending on the value of the "blocking" 396 * parameter. 397 */ 398 399 enum { 400 NO_MORE_BUFFERS = 0x80000001, 401 STOPPED = 1 402 }; 403 404 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 405 void releaseBuffer(Buffer* audioBuffer); 406 407 408 /* As a convenience we provide a write() interface to the audio buffer. 409 * This is implemented on top of lockBuffer/unlockBuffer. For best 410 * performance 411 * 412 */ 413 ssize_t write(const void* buffer, size_t size); 414 415 /* 416 * Dumps the state of an audio track. 417 */ 418 status_t dump(int fd, const Vector<String16>& args) const; 419 420private: 421 /* copying audio tracks is not allowed */ 422 AudioTrack(const AudioTrack& other); 423 AudioTrack& operator = (const AudioTrack& other); 424 425 /* a small internal class to handle the callback */ 426 class AudioTrackThread : public Thread 427 { 428 public: 429 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 430 private: 431 friend class AudioTrack; 432 virtual bool threadLoop(); 433 virtual status_t readyToRun(); 434 virtual void onFirstRef(); 435 AudioTrack& mReceiver; 436 Mutex mLock; 437 }; 438 439 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 440 status_t createTrack_l(int streamType, 441 uint32_t sampleRate, 442 int format, 443 int channelCount, 444 int frameCount, 445 uint32_t flags, 446 const sp<IMemory>& sharedBuffer, 447 audio_io_handle_t output, 448 bool enforceFrameCount); 449 void flush_l(); 450 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 451 audio_io_handle_t getOutput_l(); 452 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 453 454 sp<IAudioTrack> mAudioTrack; 455 sp<IMemory> mCblkMemory; 456 sp<AudioTrackThread> mAudioTrackThread; 457 458 float mVolume[2]; 459 float mSendLevel; 460 uint32_t mFrameCount; 461 462 audio_track_cblk_t* mCblk; 463 uint8_t mStreamType; 464 uint8_t mFormat; 465 uint8_t mChannelCount; 466 uint8_t mMuted; 467 uint32_t mChannels; 468 status_t mStatus; 469 uint32_t mLatency; 470 471 volatile int32_t mActive; 472 473 callback_t mCbf; 474 void* mUserData; 475 uint32_t mNotificationFramesReq; // requested number of frames between each notification callback 476 uint32_t mNotificationFramesAct; // actual number of frames between each notification callback 477 sp<IMemory> mSharedBuffer; 478 int mLoopCount; 479 uint32_t mRemainingFrames; 480 uint32_t mMarkerPosition; 481 bool mMarkerReached; 482 uint32_t mNewPosition; 483 uint32_t mUpdatePeriod; 484 uint32_t mFlags; 485 int mSessionId; 486 int mAuxEffectId; 487 Mutex mLock; 488}; 489 490 491}; // namespace android 492 493#endif // ANDROID_AUDIOTRACK_H 494