AudioTrack.h revision 362c4e697d8e9c034e964ac7b40227e054491547
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; // signed 16-bit 79 int8_t* i8; // unsigned 8-bit, offset by 0x80 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 available 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 uint32_t containing the marker position in frames. 98 * - EVENT_NEW_POS: pointer to an uint32_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 * user: Context for use by the callback receiver. 139 * notificationFrames: The callback function is called each time notificationFrames PCM 140 * frames have been consumed from track input buffer. 141 * sessionId: Specific session ID, or zero to use default. 142 */ 143 144 AudioTrack( int streamType, 145 uint32_t sampleRate = 0, 146 int format = 0, 147 int channelMask = 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 in memory before the AudioTrack is started. 159 * The write() and flush() methods are not supported in this case. 160 * It is recommended 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 channelMask = 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 associated 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 initialization 184 * - INVALID_OPERATION: AudioTrack is already initialized 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 channelMask = 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()), because 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 estimated 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 stopped. 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 unmute this track. 249 * While muted, the callback, if set, is still called. 250 */ 251 void mute(bool); 252 bool muted() const; 253 254 /* Set volume for this track, mostly used for games' sound effects 255 * left and right volumes. Levels must be >= 0.0 and <= 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 >= 0.0 and <= 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 278 * pending or 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 /* Sets marker position. When playback reaches the number of frames specified, a callback with 287 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 288 * notification callback. 289 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 290 * 291 * Parameters: 292 * 293 * marker: marker position expressed in frames. 294 * 295 * Returned status (from utils/Errors.h) can be: 296 * - NO_ERROR: successful operation 297 * - INVALID_OPERATION: the AudioTrack has no callback installed. 298 */ 299 status_t setMarkerPosition(uint32_t marker); 300 status_t getMarkerPosition(uint32_t *marker); 301 302 303 /* Sets position update period. Every time the number of frames specified has been played, 304 * a callback with event type EVENT_NEW_POS is called. 305 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 306 * callback. 307 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 308 * 309 * Parameters: 310 * 311 * updatePeriod: position update notification period expressed in frames. 312 * 313 * Returned status (from utils/Errors.h) can be: 314 * - NO_ERROR: successful operation 315 * - INVALID_OPERATION: the AudioTrack has no callback installed. 316 */ 317 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 318 status_t getPositionUpdatePeriod(uint32_t *updatePeriod); 319 320 /* Sets playback head position within AudioTrack buffer. The new position is specified 321 * in number of frames. 322 * This method must be called with the AudioTrack in paused or stopped state. 323 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 324 * Therefore using this method makes sense only when playing a "static" audio buffer 325 * as opposed to streaming. 326 * The getPosition() method on the other hand returns the total number of frames played since 327 * playback start. 328 * 329 * Parameters: 330 * 331 * position: New playback head position within AudioTrack buffer. 332 * 333 * Returned status (from utils/Errors.h) can be: 334 * - NO_ERROR: successful operation 335 * - INVALID_OPERATION: the AudioTrack is not stopped. 336 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 337 */ 338 status_t setPosition(uint32_t position); 339 status_t getPosition(uint32_t *position); 340 341 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 342 * rewriting the buffer before restarting playback after a stop. 343 * This method must be called with the AudioTrack in paused or stopped state. 344 * 345 * Returned status (from utils/Errors.h) can be: 346 * - NO_ERROR: successful operation 347 * - INVALID_OPERATION: the AudioTrack is not stopped. 348 */ 349 status_t reload(); 350 351 /* Returns a handle on the audio output used by this AudioTrack. 352 * 353 * Parameters: 354 * none. 355 * 356 * Returned value: 357 * handle on audio hardware output 358 */ 359 audio_io_handle_t getOutput(); 360 361 /* Returns the unique session ID associated with this track. 362 * 363 * Parameters: 364 * none. 365 * 366 * Returned value: 367 * AudioTrack session ID. 368 */ 369 int getSessionId(); 370 371 /* Attach track auxiliary output to specified effect. Use effectId = 0 372 * to detach track from effect. 373 * 374 * Parameters: 375 * 376 * effectId: effectId obtained from AudioEffect::id(). 377 * 378 * Returned status (from utils/Errors.h) can be: 379 * - NO_ERROR: successful operation 380 * - INVALID_OPERATION: the effect is not an auxiliary effect. 381 * - BAD_VALUE: The specified effect ID is invalid 382 */ 383 status_t attachAuxEffect(int effectId); 384 385 /* Obtains a buffer of "frameCount" frames. The buffer must be 386 * filled entirely. If the track is stopped, obtainBuffer() returns 387 * STOPPED instead of NO_ERROR as long as there are buffers available, 388 * at which point NO_MORE_BUFFERS is returned. 389 * Buffers will be returned until the pool (buffercount()) 390 * is exhausted, at which point obtainBuffer() will either block 391 * or return WOULD_BLOCK depending on the value of the "blocking" 392 * parameter. 393 */ 394 395 enum { 396 NO_MORE_BUFFERS = 0x80000001, 397 STOPPED = 1 398 }; 399 400 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 401 void releaseBuffer(Buffer* audioBuffer); 402 403 /* As a convenience we provide a write() interface to the audio buffer. 404 * This is implemented on top of lockBuffer/unlockBuffer. For best 405 * performance use callbacks. Return actual number of bytes written. 406 * 407 */ 408 ssize_t write(const void* buffer, size_t size); 409 410 /* 411 * Dumps the state of an audio track. 412 */ 413 status_t dump(int fd, const Vector<String16>& args) const; 414 415private: 416 /* copying audio tracks is not allowed */ 417 AudioTrack(const AudioTrack& other); 418 AudioTrack& operator = (const AudioTrack& other); 419 420 /* a small internal class to handle the callback */ 421 class AudioTrackThread : public Thread 422 { 423 public: 424 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 425 private: 426 friend class AudioTrack; 427 virtual bool threadLoop(); 428 virtual status_t readyToRun(); 429 virtual void onFirstRef(); 430 AudioTrack& mReceiver; 431 Mutex mLock; 432 }; 433 434 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 435 status_t createTrack_l(int streamType, 436 uint32_t sampleRate, 437 uint32_t format, 438 uint32_t channelMask, 439 int frameCount, 440 uint32_t flags, 441 const sp<IMemory>& sharedBuffer, 442 audio_io_handle_t output, 443 bool enforceFrameCount); 444 void flush_l(); 445 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 446 audio_io_handle_t getOutput_l(); 447 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 448 449 sp<IAudioTrack> mAudioTrack; 450 sp<IMemory> mCblkMemory; 451 sp<AudioTrackThread> mAudioTrackThread; 452 453 float mVolume[2]; 454 float mSendLevel; 455 uint32_t mFrameCount; 456 457 audio_track_cblk_t* mCblk; 458 uint32_t mFormat; 459 uint8_t mStreamType; 460 uint8_t mChannelCount; 461 uint8_t mMuted; 462 uint8_t mReserved; 463 uint32_t mChannelMask; 464 status_t mStatus; 465 uint32_t mLatency; 466 467 volatile int32_t mActive; 468 469 callback_t mCbf; 470 void* mUserData; 471 uint32_t mNotificationFramesReq; // requested number of frames between each notification callback 472 uint32_t mNotificationFramesAct; // actual number of frames between each notification callback 473 sp<IMemory> mSharedBuffer; 474 int mLoopCount; 475 uint32_t mRemainingFrames; 476 uint32_t mMarkerPosition; 477 bool mMarkerReached; 478 uint32_t mNewPosition; 479 uint32_t mUpdatePeriod; 480 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 481 uint32_t mFlags; 482 int mSessionId; 483 int mAuxEffectId; 484 Mutex mLock; 485 status_t mRestoreStatus; 486 int mPreviousPriority; // before start() 487 int mPreviousSchedulingGroup; 488}; 489 490 491}; // namespace android 492 493#endif // ANDROID_AUDIOTRACK_H 494