AudioTrack.h revision b68a91a70bc8d0d18e7404e14443d4e4020b3635
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 /* Create Buffer on the stack and pass it to obtainBuffer() 62 * and releaseBuffer(). 63 */ 64 65 class Buffer 66 { 67 public: 68 enum { 69 MUTE = 0x00000001 70 }; 71 uint32_t flags; 72 int format; 73 int channelCount; // will be removed in the future, do not use 74 size_t frameCount; 75 size_t size; 76 union { 77 void* raw; 78 short* i16; 79 int8_t* i8; 80 }; 81 }; 82 83 84 /* As a convenience, if a callback is supplied, a handler thread 85 * is automatically created with the appropriate priority. This thread 86 * invokes the callback when a new buffer becomes availlable or an underrun condition occurs. 87 * Parameters: 88 * 89 * event: type of event notified (see enum AudioTrack::event_type). 90 * user: Pointer to context for use by the callback receiver. 91 * info: Pointer to optional parameter according to event type: 92 * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write 93 * more bytes than indicated by 'size' field and update 'size' if less bytes are 94 * written. 95 * - EVENT_UNDERRUN: unused. 96 * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. 97 * - EVENT_MARKER: pointer to an uin32_t containing the marker position in frames. 98 * - EVENT_NEW_POS: pointer to an uin32_t containing the new position in frames. 99 * - EVENT_BUFFER_END: unused. 100 */ 101 102 typedef void (*callback_t)(int event, void* user, void *info); 103 104 /* Returns the minimum frame count required for the successful creation of 105 * an AudioTrack object. 106 * Returned status (from utils/Errors.h) can be: 107 * - NO_ERROR: successful operation 108 * - NO_INIT: audio server or audio hardware not initialized 109 */ 110 111 static status_t getMinFrameCount(int* frameCount, 112 int streamType =-1, 113 uint32_t sampleRate = 0); 114 115 /* Constructs an uninitialized AudioTrack. No connection with 116 * AudioFlinger takes place. 117 */ 118 AudioTrack(); 119 120 /* Creates an audio track and registers it with AudioFlinger. 121 * Once created, the track needs to be started before it can be used. 122 * Unspecified values are set to the audio hardware's current 123 * values. 124 * 125 * Parameters: 126 * 127 * streamType: Select the type of audio stream this track is attached to 128 * (e.g. AUDIO_STREAM_MUSIC). 129 * sampleRate: Track sampling rate in Hz. 130 * format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed 131 * 16 bits per sample). 132 * channelMask: Channel mask: see audio_channels_t. 133 * frameCount: Total size of track PCM buffer in frames. This defines the 134 * latency of the track. 135 * flags: Reserved for future use. 136 * cbf: Callback function. If not null, this function is called periodically 137 * to request new PCM data. 138 * notificationFrames: The callback function is called each time notificationFrames PCM 139 * frames have been comsumed from track input buffer. 140 * user Context for use by the callback receiver. 141 */ 142 143 AudioTrack( int streamType, 144 uint32_t sampleRate = 0, 145 int format = 0, 146 int channelMask = 0, 147 int frameCount = 0, 148 uint32_t flags = 0, 149 callback_t cbf = 0, 150 void* user = 0, 151 int notificationFrames = 0, 152 int sessionId = 0); 153 154 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 155 * The PCM data to be rendered by AudioTrack is passed in a shared memory buffer 156 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 157 * PCM data must be present into memory before the AudioTrack is started. 158 * The Write() and Flush() methods are not supported in this case. 159 * It is recommented to pass a callback function to be notified of playback end by an 160 * EVENT_UNDERRUN event. 161 */ 162 163 AudioTrack( int streamType, 164 uint32_t sampleRate = 0, 165 int format = 0, 166 int channelMask = 0, 167 const sp<IMemory>& sharedBuffer = 0, 168 uint32_t flags = 0, 169 callback_t cbf = 0, 170 void* user = 0, 171 int notificationFrames = 0, 172 int sessionId = 0); 173 174 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 175 * Also destroys all resources assotiated with the AudioTrack. 176 */ 177 ~AudioTrack(); 178 179 180 /* Initialize an uninitialized AudioTrack. 181 * Returned status (from utils/Errors.h) can be: 182 * - NO_ERROR: successful intialization 183 * - INVALID_OPERATION: AudioTrack is already intitialized 184 * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) 185 * - NO_INIT: audio server or audio hardware not initialized 186 * */ 187 status_t set(int streamType =-1, 188 uint32_t sampleRate = 0, 189 int format = 0, 190 int channelMask = 0, 191 int frameCount = 0, 192 uint32_t flags = 0, 193 callback_t cbf = 0, 194 void* user = 0, 195 int notificationFrames = 0, 196 const sp<IMemory>& sharedBuffer = 0, 197 bool threadCanCallJava = false, 198 int sessionId = 0); 199 200 201 /* Result of constructing the AudioTrack. This must be checked 202 * before using any AudioTrack API (except for set()), using 203 * an uninitialized AudioTrack produces undefined results. 204 * See set() method above for possible return codes. 205 */ 206 status_t initCheck() const; 207 208 /* Returns this track's latency in milliseconds. 209 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 210 * and audio hardware driver. 211 */ 212 uint32_t latency() const; 213 214 /* getters, see constructor */ 215 216 int streamType() const; 217 int format() const; 218 int channelCount() const; 219 uint32_t frameCount() const; 220 int frameSize() const; 221 sp<IMemory>& sharedBuffer(); 222 223 224 /* After it's created the track is not active. Call start() to 225 * make it active. If set, the callback will start being called. 226 */ 227 void start(); 228 229 /* Stop a track. If set, the callback will cease being called and 230 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 231 * and will fill up buffers until the pool is exhausted. 232 */ 233 void stop(); 234 bool stopped() const; 235 236 /* flush a stopped track. All pending buffers are discarded. 237 * This function has no effect if the track is not stoped. 238 */ 239 void flush(); 240 241 /* Pause a track. If set, the callback will cease being called and 242 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 243 * and will fill up buffers until the pool is exhausted. 244 */ 245 void pause(); 246 247 /* mute or unmutes this track. 248 * While mutted, the callback, if set, is still called. 249 */ 250 void mute(bool); 251 bool muted() const; 252 253 254 /* set volume for this track, mostly used for games' sound effects 255 * left and right volumes. Levels must be <= 1.0. 256 */ 257 status_t setVolume(float left, float right); 258 void getVolume(float* left, float* right); 259 260 /* set the send level for this track. An auxiliary effect should be attached 261 * to the track with attachEffect(). Level must be <= 1.0. 262 */ 263 status_t setAuxEffectSendLevel(float level); 264 void getAuxEffectSendLevel(float* level); 265 266 /* set sample rate for this track, mostly used for games' sound effects 267 */ 268 status_t setSampleRate(int sampleRate); 269 uint32_t getSampleRate(); 270 271 /* Enables looping and sets the start and end points of looping. 272 * 273 * Parameters: 274 * 275 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 276 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 277 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any pending or 278 * active loop. loopCount = -1 means infinite looping. 279 * 280 * For proper operation the following condition must be respected: 281 * (loopEnd-loopStart) <= framecount() 282 */ 283 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 284 status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount); 285 286 287 /* Sets marker position. When playback reaches the number of frames specified, a callback with event 288 * type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker notification 289 * callback. 290 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 291 * 292 * Parameters: 293 * 294 * marker: marker position expressed in frames. 295 * 296 * Returned status (from utils/Errors.h) can be: 297 * - NO_ERROR: successful operation 298 * - INVALID_OPERATION: the AudioTrack has no callback installed. 299 */ 300 status_t setMarkerPosition(uint32_t marker); 301 status_t getMarkerPosition(uint32_t *marker); 302 303 304 /* Sets position update period. Every time the number of frames specified has been played, 305 * a callback with event type EVENT_NEW_POS is called. 306 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 307 * callback. 308 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 309 * 310 * Parameters: 311 * 312 * updatePeriod: position update notification period 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 setPositionUpdatePeriod(uint32_t updatePeriod); 319 status_t getPositionUpdatePeriod(uint32_t *updatePeriod); 320 321 322 /* Sets playback head position within AudioTrack buffer. The new position is specified 323 * in number of frames. 324 * This method must be called with the AudioTrack in paused or stopped state. 325 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 326 * Therefore using this method makes sense only when playing a "static" audio buffer 327 * as opposed to streaming. 328 * The getPosition() method on the other hand returns the total number of frames played since 329 * playback start. 330 * 331 * Parameters: 332 * 333 * position: New playback head position within AudioTrack buffer. 334 * 335 * Returned status (from utils/Errors.h) can be: 336 * - NO_ERROR: successful operation 337 * - INVALID_OPERATION: the AudioTrack is not stopped. 338 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 339 */ 340 status_t setPosition(uint32_t position); 341 status_t getPosition(uint32_t *position); 342 343 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 344 * rewriting the buffer before restarting playback after a stop. 345 * This method must be called with the AudioTrack in paused or stopped state. 346 * 347 * Returned status (from utils/Errors.h) can be: 348 * - NO_ERROR: successful operation 349 * - INVALID_OPERATION: the AudioTrack is not stopped. 350 */ 351 status_t reload(); 352 353 /* returns a handle on the audio output used by this AudioTrack. 354 * 355 * Parameters: 356 * none. 357 * 358 * Returned value: 359 * handle on audio hardware output 360 */ 361 audio_io_handle_t getOutput(); 362 363 /* returns the unique ID associated to this track. 364 * 365 * Parameters: 366 * none. 367 * 368 * Returned value: 369 * AudioTrack ID. 370 */ 371 int getSessionId(); 372 373 374 /* Attach track auxiliary output to specified effect. Used effectId = 0 375 * to detach track from effect. 376 * 377 * Parameters: 378 * 379 * effectId: effectId obtained from AudioEffect::id(). 380 * 381 * Returned status (from utils/Errors.h) can be: 382 * - NO_ERROR: successful operation 383 * - INVALID_OPERATION: the effect is not an auxiliary effect. 384 * - BAD_VALUE: The specified effect ID is invalid 385 */ 386 status_t attachAuxEffect(int effectId); 387 388 /* obtains a buffer of "frameCount" frames. The buffer must be 389 * filled entirely. If the track is stopped, obtainBuffer() returns 390 * STOPPED instead of NO_ERROR as long as there are buffers availlable, 391 * at which point NO_MORE_BUFFERS is returned. 392 * Buffers will be returned until the pool (buffercount()) 393 * is exhausted, at which point obtainBuffer() will either block 394 * or return WOULD_BLOCK depending on the value of the "blocking" 395 * parameter. 396 */ 397 398 enum { 399 NO_MORE_BUFFERS = 0x80000001, 400 STOPPED = 1 401 }; 402 403 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 404 void releaseBuffer(Buffer* audioBuffer); 405 406 407 /* As a convenience we provide a write() interface to the audio buffer. 408 * This is implemented on top of lockBuffer/unlockBuffer. For best 409 * performance 410 * 411 */ 412 ssize_t write(const void* buffer, size_t size); 413 414 /* 415 * Dumps the state of an audio track. 416 */ 417 status_t dump(int fd, const Vector<String16>& args) const; 418 419private: 420 /* copying audio tracks is not allowed */ 421 AudioTrack(const AudioTrack& other); 422 AudioTrack& operator = (const AudioTrack& other); 423 424 /* a small internal class to handle the callback */ 425 class AudioTrackThread : public Thread 426 { 427 public: 428 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 429 private: 430 friend class AudioTrack; 431 virtual bool threadLoop(); 432 virtual status_t readyToRun(); 433 virtual void onFirstRef(); 434 AudioTrack& mReceiver; 435 Mutex mLock; 436 }; 437 438 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 439 status_t createTrack_l(int streamType, 440 uint32_t sampleRate, 441 uint32_t format, 442 uint32_t channelMask, 443 int frameCount, 444 uint32_t flags, 445 const sp<IMemory>& sharedBuffer, 446 audio_io_handle_t output, 447 bool enforceFrameCount); 448 void flush_l(); 449 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 450 audio_io_handle_t getOutput_l(); 451 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 452 453 sp<IAudioTrack> mAudioTrack; 454 sp<IMemory> mCblkMemory; 455 sp<AudioTrackThread> mAudioTrackThread; 456 457 float mVolume[2]; 458 float mSendLevel; 459 uint32_t mFrameCount; 460 461 audio_track_cblk_t* mCblk; 462 uint32_t mFormat; 463 uint8_t mStreamType; 464 uint8_t mChannelCount; 465 uint8_t mMuted; 466 uint8_t mReserved; 467 uint32_t mChannelMask; 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 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 485 uint32_t mFlags; 486 int mSessionId; 487 int mAuxEffectId; 488 Mutex mLock; 489 status_t mRestoreStatus; 490}; 491 492 493}; // namespace android 494 495#endif // ANDROID_AUDIOTRACK_H 496