AudioTrack.h revision a0d68338a88c2ddb4502f95017b546d603ef1ec7
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 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 size_t frameCount; 76 size_t size; 77 union { 78 void* raw; 79 short* i16; // signed 16-bit 80 int8_t* i8; // unsigned 8-bit, offset by 0x80 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 available 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 uint32_t containing the marker position in frames. 99 * - EVENT_NEW_POS: pointer to an uint32_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 audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 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. AUDIO_STREAM_MUSIC). 130 * sampleRate: Track sampling rate in Hz. 131 * format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed 132 * 16 bits per sample). 133 * channelMask: Channel mask: see audio_channels_t. 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 * user: Context for use by the callback receiver. 140 * notificationFrames: The callback function is called each time notificationFrames PCM 141 * frames have been consumed from track input buffer. 142 * sessionId: Specific session ID, or zero to use default. 143 */ 144 145 AudioTrack( audio_stream_type_t streamType, 146 uint32_t sampleRate = 0, 147 audio_format_t format = AUDIO_FORMAT_DEFAULT, 148 int channelMask = 0, 149 int frameCount = 0, 150 uint32_t flags = 0, 151 callback_t cbf = NULL, 152 void* user = NULL, 153 int notificationFrames = 0, 154 int sessionId = 0); 155 156 // DEPRECATED 157 explicit AudioTrack( int streamType, 158 uint32_t sampleRate = 0, 159 int format = AUDIO_FORMAT_DEFAULT, 160 int channelMask = 0, 161 int frameCount = 0, 162 uint32_t flags = 0, 163 callback_t cbf = 0, 164 void* user = 0, 165 int notificationFrames = 0, 166 int sessionId = 0); 167 168 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 169 * the PCM data to be rendered by AudioTrack is passed in a shared memory buffer 170 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 171 * PCM data must be present in memory before the AudioTrack is started. 172 * The write() and flush() methods are not supported in this case. 173 * It is recommended to pass a callback function to be notified of playback end by an 174 * EVENT_UNDERRUN event. 175 */ 176 177 AudioTrack( audio_stream_type_t streamType, 178 uint32_t sampleRate = 0, 179 audio_format_t format = AUDIO_FORMAT_DEFAULT, 180 int channelMask = 0, 181 const sp<IMemory>& sharedBuffer = 0, 182 uint32_t flags = 0, 183 callback_t cbf = NULL, 184 void* user = NULL, 185 int notificationFrames = 0, 186 int sessionId = 0); 187 188 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 189 * Also destroys all resources associated with the AudioTrack. 190 */ 191 ~AudioTrack(); 192 193 194 /* Initialize an uninitialized AudioTrack. 195 * Returned status (from utils/Errors.h) can be: 196 * - NO_ERROR: successful initialization 197 * - INVALID_OPERATION: AudioTrack is already initialized 198 * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) 199 * - NO_INIT: audio server or audio hardware not initialized 200 * */ 201 status_t set(audio_stream_type_t streamType = AUDIO_STREAM_DEFAULT, 202 uint32_t sampleRate = 0, 203 audio_format_t format = AUDIO_FORMAT_DEFAULT, 204 int channelMask = 0, 205 int frameCount = 0, 206 uint32_t flags = 0, 207 callback_t cbf = NULL, 208 void* user = NULL, 209 int notificationFrames = 0, 210 const sp<IMemory>& sharedBuffer = 0, 211 bool threadCanCallJava = false, 212 int sessionId = 0); 213 214 215 /* Result of constructing the AudioTrack. This must be checked 216 * before using any AudioTrack API (except for set()), because using 217 * an uninitialized AudioTrack produces undefined results. 218 * See set() method above for possible return codes. 219 */ 220 status_t initCheck() const; 221 222 /* Returns this track's estimated latency in milliseconds. 223 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 224 * and audio hardware driver. 225 */ 226 uint32_t latency() const; 227 228 /* getters, see constructor */ 229 230 audio_stream_type_t streamType() const; 231 audio_format_t format() const; 232 int channelCount() const; 233 uint32_t frameCount() const; 234 235 /* Return channelCount * (bit depth per channel / 8). 236 * channelCount is determined from channelMask, and bit depth comes from format. 237 */ 238 size_t frameSize() const; 239 240 sp<IMemory>& sharedBuffer(); 241 242 243 /* After it's created the track is not active. Call start() to 244 * make it active. If set, the callback will start being called. 245 */ 246 void start(); 247 248 /* Stop a track. If set, the callback will cease being called and 249 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 250 * and will fill up buffers until the pool is exhausted. 251 */ 252 void stop(); 253 bool stopped() const; 254 255 /* Flush a stopped track. All pending buffers are discarded. 256 * This function has no effect if the track is not stopped. 257 */ 258 void flush(); 259 260 /* Pause a track. If set, the callback will cease being called and 261 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 262 * and will fill up buffers until the pool is exhausted. 263 */ 264 void pause(); 265 266 /* Mute or unmute this track. 267 * While muted, the callback, if set, is still called. 268 */ 269 void mute(bool); 270 bool muted() const; 271 272 /* Set volume for this track, mostly used for games' sound effects 273 * left and right volumes. Levels must be >= 0.0 and <= 1.0. 274 */ 275 status_t setVolume(float left, float right); 276 void getVolume(float* left, float* right); 277 278 /* Set the send level for this track. An auxiliary effect should be attached 279 * to the track with attachEffect(). Level must be >= 0.0 and <= 1.0. 280 */ 281 status_t setAuxEffectSendLevel(float level); 282 void getAuxEffectSendLevel(float* level); 283 284 /* Set sample rate for this track, mostly used for games' sound effects 285 */ 286 status_t setSampleRate(int sampleRate); 287 uint32_t getSampleRate(); 288 289 /* Enables looping and sets the start and end points of looping. 290 * 291 * Parameters: 292 * 293 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 294 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 295 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any 296 * pending or active loop. loopCount = -1 means infinite looping. 297 * 298 * For proper operation the following condition must be respected: 299 * (loopEnd-loopStart) <= framecount() 300 */ 301 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 302 status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount); 303 304 /* Sets marker position. When playback reaches the number of frames specified, a callback with 305 * event type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker 306 * notification callback. 307 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 308 * 309 * Parameters: 310 * 311 * marker: marker position 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 setMarkerPosition(uint32_t marker); 318 status_t getMarkerPosition(uint32_t *marker); 319 320 321 /* Sets position update period. Every time the number of frames specified has been played, 322 * a callback with event type EVENT_NEW_POS is called. 323 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 324 * callback. 325 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 326 * 327 * Parameters: 328 * 329 * updatePeriod: position update notification period expressed in frames. 330 * 331 * Returned status (from utils/Errors.h) can be: 332 * - NO_ERROR: successful operation 333 * - INVALID_OPERATION: the AudioTrack has no callback installed. 334 */ 335 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 336 status_t getPositionUpdatePeriod(uint32_t *updatePeriod); 337 338 /* Sets playback head position within AudioTrack buffer. The new position is specified 339 * in number of frames. 340 * This method must be called with the AudioTrack in paused or stopped state. 341 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 342 * Therefore using this method makes sense only when playing a "static" audio buffer 343 * as opposed to streaming. 344 * The getPosition() method on the other hand returns the total number of frames played since 345 * playback start. 346 * 347 * Parameters: 348 * 349 * position: New playback head position within AudioTrack buffer. 350 * 351 * Returned status (from utils/Errors.h) can be: 352 * - NO_ERROR: successful operation 353 * - INVALID_OPERATION: the AudioTrack is not stopped. 354 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 355 */ 356 status_t setPosition(uint32_t position); 357 status_t getPosition(uint32_t *position); 358 359 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 360 * rewriting the buffer before restarting playback after a stop. 361 * This method must be called with the AudioTrack in paused or stopped state. 362 * 363 * Returned status (from utils/Errors.h) can be: 364 * - NO_ERROR: successful operation 365 * - INVALID_OPERATION: the AudioTrack is not stopped. 366 */ 367 status_t reload(); 368 369 /* Returns a handle on the audio output used by this AudioTrack. 370 * 371 * Parameters: 372 * none. 373 * 374 * Returned value: 375 * handle on audio hardware output 376 */ 377 audio_io_handle_t getOutput(); 378 379 /* Returns the unique session ID associated with this track. 380 * 381 * Parameters: 382 * none. 383 * 384 * Returned value: 385 * AudioTrack session ID. 386 */ 387 int getSessionId(); 388 389 /* Attach track auxiliary output to specified effect. Use effectId = 0 390 * to detach track from effect. 391 * 392 * Parameters: 393 * 394 * effectId: effectId obtained from AudioEffect::id(). 395 * 396 * Returned status (from utils/Errors.h) can be: 397 * - NO_ERROR: successful operation 398 * - INVALID_OPERATION: the effect is not an auxiliary effect. 399 * - BAD_VALUE: The specified effect ID is invalid 400 */ 401 status_t attachAuxEffect(int effectId); 402 403 /* Obtains a buffer of "frameCount" frames. The buffer must be 404 * filled entirely. If the track is stopped, obtainBuffer() returns 405 * STOPPED instead of NO_ERROR as long as there are buffers available, 406 * at which point NO_MORE_BUFFERS is returned. 407 * Buffers will be returned until the pool (buffercount()) 408 * is exhausted, at which point obtainBuffer() will either block 409 * or return WOULD_BLOCK depending on the value of the "blocking" 410 * parameter. 411 */ 412 413 enum { 414 NO_MORE_BUFFERS = 0x80000001, // same name in AudioFlinger.h, ok to be different value 415 STOPPED = 1 416 }; 417 418 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 419 void releaseBuffer(Buffer* audioBuffer); 420 421 /* As a convenience we provide a write() interface to the audio buffer. 422 * This is implemented on top of lockBuffer/unlockBuffer. For best 423 * performance use callbacks. Return actual number of bytes written. 424 * 425 */ 426 ssize_t write(const void* buffer, size_t size); 427 428 /* 429 * Dumps the state of an audio track. 430 */ 431 status_t dump(int fd, const Vector<String16>& args) const; 432 433private: 434 /* copying audio tracks is not allowed */ 435 AudioTrack(const AudioTrack& other); 436 AudioTrack& operator = (const AudioTrack& other); 437 438 /* a small internal class to handle the callback */ 439 class AudioTrackThread : public Thread 440 { 441 public: 442 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 443 private: 444 friend class AudioTrack; 445 virtual bool threadLoop(); 446 virtual status_t readyToRun(); 447 virtual void onFirstRef(); 448 AudioTrack& mReceiver; 449 Mutex mLock; 450 }; 451 452 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 453 status_t createTrack_l(audio_stream_type_t streamType, 454 uint32_t sampleRate, 455 audio_format_t format, 456 uint32_t channelMask, 457 int frameCount, 458 uint32_t flags, 459 const sp<IMemory>& sharedBuffer, 460 audio_io_handle_t output, 461 bool enforceFrameCount); 462 void flush_l(); 463 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 464 audio_io_handle_t getOutput_l(); 465 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 466 bool stopped_l() const { return !mActive; } 467 468 sp<IAudioTrack> mAudioTrack; 469 sp<IMemory> mCblkMemory; 470 sp<AudioTrackThread> mAudioTrackThread; 471 472 float mVolume[2]; 473 float mSendLevel; 474 uint32_t mFrameCount; 475 476 audio_track_cblk_t* mCblk; 477 audio_format_t mFormat; 478 audio_stream_type_t mStreamType; 479 uint8_t mChannelCount; 480 uint8_t mMuted; 481 uint8_t mReserved; 482 uint32_t mChannelMask; 483 status_t mStatus; 484 uint32_t mLatency; 485 486 bool mActive; // protected by mLock 487 488 callback_t mCbf; 489 void* mUserData; 490 uint32_t mNotificationFramesReq; // requested number of frames between each notification callback 491 uint32_t mNotificationFramesAct; // actual number of frames between each notification callback 492 sp<IMemory> mSharedBuffer; 493 int mLoopCount; 494 uint32_t mRemainingFrames; 495 uint32_t mMarkerPosition; 496 bool mMarkerReached; 497 uint32_t mNewPosition; 498 uint32_t mUpdatePeriod; 499 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 500 uint32_t mFlags; 501 int mSessionId; 502 int mAuxEffectId; 503 mutable Mutex mLock; 504 status_t mRestoreStatus; 505 int mPreviousPriority; // before start() 506 int mPreviousSchedulingGroup; 507}; 508 509 510}; // namespace android 511 512#endif // ANDROID_AUDIOTRACK_H 513