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 namespace android { 34 35 // ---------------------------------------------------------------------------- 36 37 class audio_track_cblk_t; 38 39 // ---------------------------------------------------------------------------- 40 41 class AudioTrack 42 { 43 public: 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: Minimum size of track PCM buffer in frames. This defines the 134 * latency of the track. The actual size selected by the AudioTrack could be 135 * larger if the requested size is not compatible with current audio HAL 136 * latency. 137 * flags: Reserved for future use. 138 * cbf: Callback function. If not null, this function is called periodically 139 * to request new PCM data. 140 * notificationFrames: The callback function is called each time notificationFrames PCM 141 * frames have been comsumed from track input buffer. 142 * user Context for use by the callback receiver. 143 */ 144 145 AudioTrack( int streamType, 146 uint32_t sampleRate = 0, 147 int format = 0, 148 int channelMask = 0, 149 int frameCount = 0, 150 uint32_t flags = 0, 151 callback_t cbf = 0, 152 void* user = 0, 153 int notificationFrames = 0, 154 int sessionId = 0); 155 156 /* Creates an audio track and registers it with AudioFlinger. With this constructor, 157 * The PCM data to be rendered by AudioTrack is passed in a shared memory buffer 158 * identified by the argument sharedBuffer. This prototype is for static buffer playback. 159 * PCM data must be present into memory before the AudioTrack is started. 160 * The Write() and Flush() methods are not supported in this case. 161 * It is recommented to pass a callback function to be notified of playback end by an 162 * EVENT_UNDERRUN event. 163 */ 164 165 AudioTrack( int streamType, 166 uint32_t sampleRate = 0, 167 int format = 0, 168 int channelMask = 0, 169 const sp<IMemory>& sharedBuffer = 0, 170 uint32_t flags = 0, 171 callback_t cbf = 0, 172 void* user = 0, 173 int notificationFrames = 0, 174 int sessionId = 0); 175 176 /* Terminates the AudioTrack and unregisters it from AudioFlinger. 177 * Also destroys all resources assotiated with the AudioTrack. 178 */ 179 ~AudioTrack(); 180 181 182 /* Initialize an uninitialized AudioTrack. 183 * Returned status (from utils/Errors.h) can be: 184 * - NO_ERROR: successful intialization 185 * - INVALID_OPERATION: AudioTrack is already intitialized 186 * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) 187 * - NO_INIT: audio server or audio hardware not initialized 188 * */ 189 status_t set(int streamType =-1, 190 uint32_t sampleRate = 0, 191 int format = 0, 192 int channelMask = 0, 193 int frameCount = 0, 194 uint32_t flags = 0, 195 callback_t cbf = 0, 196 void* user = 0, 197 int notificationFrames = 0, 198 const sp<IMemory>& sharedBuffer = 0, 199 bool threadCanCallJava = false, 200 int sessionId = 0); 201 202 203 /* Result of constructing the AudioTrack. This must be checked 204 * before using any AudioTrack API (except for set()), using 205 * an uninitialized AudioTrack produces undefined results. 206 * See set() method above for possible return codes. 207 */ 208 status_t initCheck() const; 209 210 /* Returns this track's latency in milliseconds. 211 * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) 212 * and audio hardware driver. 213 */ 214 uint32_t latency() const; 215 216 /* getters, see constructor */ 217 218 int streamType() const; 219 int format() const; 220 int channelCount() const; 221 uint32_t frameCount() const; 222 int frameSize() const; 223 sp<IMemory>& sharedBuffer(); 224 225 226 /* After it's created the track is not active. Call start() to 227 * make it active. If set, the callback will start being called. 228 */ 229 void start(); 230 231 /* Stop a track. If set, the callback will cease being called and 232 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 233 * and will fill up buffers until the pool is exhausted. 234 */ 235 void stop(); 236 bool stopped() const; 237 238 /* flush a stopped track. All pending buffers are discarded. 239 * This function has no effect if the track is not stoped. 240 */ 241 void flush(); 242 243 /* Pause a track. If set, the callback will cease being called and 244 * obtainBuffer returns STOPPED. Note that obtainBuffer() still works 245 * and will fill up buffers until the pool is exhausted. 246 */ 247 void pause(); 248 249 /* mute or unmutes this track. 250 * While mutted, the callback, if set, is still called. 251 */ 252 void mute(bool); 253 bool muted() const; 254 255 256 /* set volume for this track, mostly used for games' sound effects 257 * left and right volumes. Levels must be <= 1.0. 258 */ 259 status_t setVolume(float left, float right); 260 void getVolume(float* left, float* right); 261 262 /* set the send level for this track. An auxiliary effect should be attached 263 * to the track with attachEffect(). Level must be <= 1.0. 264 */ 265 status_t setAuxEffectSendLevel(float level); 266 void getAuxEffectSendLevel(float* level); 267 268 /* set sample rate for this track, mostly used for games' sound effects 269 */ 270 status_t setSampleRate(int sampleRate); 271 uint32_t getSampleRate(); 272 273 /* Enables looping and sets the start and end points of looping. 274 * 275 * Parameters: 276 * 277 * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. 278 * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. 279 * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any pending or 280 * active loop. loopCount = -1 means infinite looping. 281 * 282 * For proper operation the following condition must be respected: 283 * (loopEnd-loopStart) <= framecount() 284 */ 285 status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); 286 status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount); 287 288 289 /* Sets marker position. When playback reaches the number of frames specified, a callback with event 290 * type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker notification 291 * callback. 292 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 293 * 294 * Parameters: 295 * 296 * marker: marker position expressed in frames. 297 * 298 * Returned status (from utils/Errors.h) can be: 299 * - NO_ERROR: successful operation 300 * - INVALID_OPERATION: the AudioTrack has no callback installed. 301 */ 302 status_t setMarkerPosition(uint32_t marker); 303 status_t getMarkerPosition(uint32_t *marker); 304 305 306 /* Sets position update period. Every time the number of frames specified has been played, 307 * a callback with event type EVENT_NEW_POS is called. 308 * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 309 * callback. 310 * If the AudioTrack has been opened with no callback function associated, the operation will fail. 311 * 312 * Parameters: 313 * 314 * updatePeriod: position update notification period expressed in frames. 315 * 316 * Returned status (from utils/Errors.h) can be: 317 * - NO_ERROR: successful operation 318 * - INVALID_OPERATION: the AudioTrack has no callback installed. 319 */ 320 status_t setPositionUpdatePeriod(uint32_t updatePeriod); 321 status_t getPositionUpdatePeriod(uint32_t *updatePeriod); 322 323 324 /* Sets playback head position within AudioTrack buffer. The new position is specified 325 * in number of frames. 326 * This method must be called with the AudioTrack in paused or stopped state. 327 * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 328 * Therefore using this method makes sense only when playing a "static" audio buffer 329 * as opposed to streaming. 330 * The getPosition() method on the other hand returns the total number of frames played since 331 * playback start. 332 * 333 * Parameters: 334 * 335 * position: New playback head position within AudioTrack buffer. 336 * 337 * Returned status (from utils/Errors.h) can be: 338 * - NO_ERROR: successful operation 339 * - INVALID_OPERATION: the AudioTrack is not stopped. 340 * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 341 */ 342 status_t setPosition(uint32_t position); 343 status_t getPosition(uint32_t *position); 344 345 /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 346 * rewriting the buffer before restarting playback after a stop. 347 * This method must be called with the AudioTrack in paused or stopped state. 348 * 349 * Returned status (from utils/Errors.h) can be: 350 * - NO_ERROR: successful operation 351 * - INVALID_OPERATION: the AudioTrack is not stopped. 352 */ 353 status_t reload(); 354 355 /* returns a handle on the audio output used by this AudioTrack. 356 * 357 * Parameters: 358 * none. 359 * 360 * Returned value: 361 * handle on audio hardware output 362 */ 363 audio_io_handle_t getOutput(); 364 365 /* returns the unique ID associated to this track. 366 * 367 * Parameters: 368 * none. 369 * 370 * Returned value: 371 * AudioTrack ID. 372 */ 373 int getSessionId(); 374 375 376 /* Attach track auxiliary output to specified effect. Used effectId = 0 377 * to detach track from effect. 378 * 379 * Parameters: 380 * 381 * effectId: effectId obtained from AudioEffect::id(). 382 * 383 * Returned status (from utils/Errors.h) can be: 384 * - NO_ERROR: successful operation 385 * - INVALID_OPERATION: the effect is not an auxiliary effect. 386 * - BAD_VALUE: The specified effect ID is invalid 387 */ 388 status_t attachAuxEffect(int effectId); 389 390 /* obtains a buffer of "frameCount" frames. The buffer must be 391 * filled entirely. If the track is stopped, obtainBuffer() returns 392 * STOPPED instead of NO_ERROR as long as there are buffers availlable, 393 * at which point NO_MORE_BUFFERS is returned. 394 * Buffers will be returned until the pool (buffercount()) 395 * is exhausted, at which point obtainBuffer() will either block 396 * or return WOULD_BLOCK depending on the value of the "blocking" 397 * parameter. 398 */ 399 400 enum { 401 NO_MORE_BUFFERS = 0x80000001, 402 STOPPED = 1 403 }; 404 405 status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); 406 void releaseBuffer(Buffer* audioBuffer); 407 408 409 /* As a convenience we provide a write() interface to the audio buffer. 410 * This is implemented on top of lockBuffer/unlockBuffer. For best 411 * performance 412 * 413 */ 414 ssize_t write(const void* buffer, size_t size); 415 416 /* 417 * Dumps the state of an audio track. 418 */ 419 status_t dump(int fd, const Vector<String16>& args) const; 420 421 private: 422 /* copying audio tracks is not allowed */ 423 AudioTrack(const AudioTrack& other); 424 AudioTrack& operator = (const AudioTrack& other); 425 426 /* a small internal class to handle the callback */ 427 class AudioTrackThread : public Thread 428 { 429 public: 430 AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); 431 private: 432 friend class AudioTrack; 433 virtual bool threadLoop(); 434 virtual status_t readyToRun(); 435 virtual void onFirstRef(); 436 AudioTrack& mReceiver; 437 Mutex mLock; 438 }; 439 440 bool processAudioBuffer(const sp<AudioTrackThread>& thread); 441 status_t createTrack_l(int streamType, 442 uint32_t sampleRate, 443 uint32_t format, 444 uint32_t channelMask, 445 int frameCount, 446 uint32_t flags, 447 const sp<IMemory>& sharedBuffer, 448 audio_io_handle_t output, 449 bool enforceFrameCount); 450 void flush_l(); 451 status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount); 452 audio_io_handle_t getOutput_l(); 453 status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart); 454 455 sp<IAudioTrack> mAudioTrack; 456 sp<IMemory> mCblkMemory; 457 sp<AudioTrackThread> mAudioTrackThread; 458 459 float mVolume[2]; 460 float mSendLevel; 461 uint32_t mFrameCount; 462 463 audio_track_cblk_t* mCblk; 464 uint32_t mFormat; 465 uint8_t mStreamType; 466 uint8_t mChannelCount; 467 uint8_t mMuted; 468 uint8_t mReserved; 469 uint32_t mChannelMask; 470 status_t mStatus; 471 uint32_t mLatency; 472 473 volatile int32_t mActive; 474 475 callback_t mCbf; 476 void* mUserData; 477 uint32_t mNotificationFramesReq; // requested number of frames between each notification callback 478 uint32_t mNotificationFramesAct; // actual number of frames between each notification callback 479 sp<IMemory> mSharedBuffer; 480 int mLoopCount; 481 uint32_t mRemainingFrames; 482 uint32_t mMarkerPosition; 483 bool mMarkerReached; 484 uint32_t mNewPosition; 485 uint32_t mUpdatePeriod; 486 bool mFlushed; // FIXME will be made obsolete by making flush() synchronous 487 uint32_t mFlags; 488 int mSessionId; 489 int mAuxEffectId; 490 Mutex mLock; 491 status_t mRestoreStatus; 492 }; 493 494 495 }; // namespace android 496 497 #endif // ANDROID_AUDIOTRACK_H 498
