/* * Copyright (C) 2007 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef ANDROID_AUDIOTRACK_H #define ANDROID_AUDIOTRACK_H #include #include #include #include #include #include #include #include #include #include namespace android { // ---------------------------------------------------------------------------- class audio_track_cblk_t; // ---------------------------------------------------------------------------- class AudioTrack { public: enum channel_index { MONO = 0, LEFT = 0, RIGHT = 1 }; /* Events used by AudioTrack callback function (audio_track_cblk_t). */ enum event_type { EVENT_MORE_DATA = 0, // Request to write more data to PCM buffer. EVENT_UNDERRUN = 1, // PCM buffer underrun occured. EVENT_LOOP_END = 2, // Sample loop end was reached; playback restarted from loop start if loop count was not 0. EVENT_MARKER = 3, // Playback head is at the specified marker position (See setMarkerPosition()). EVENT_NEW_POS = 4, // Playback head is at a new position (See setPositionUpdatePeriod()). EVENT_BUFFER_END = 5 // Playback head is at the end of the buffer. }; /* Create Buffer on the stack and pass it to obtainBuffer() * and releaseBuffer(). */ class Buffer { public: enum { MUTE = 0x00000001 }; uint32_t flags; int channelCount; int format; size_t frameCount; size_t size; union { void* raw; short* i16; int8_t* i8; }; }; /* As a convenience, if a callback is supplied, a handler thread * is automatically created with the appropriate priority. This thread * invokes the callback when a new buffer becomes availlable or an underrun condition occurs. * Parameters: * * event: type of event notified (see enum AudioTrack::event_type). * user: Pointer to context for use by the callback receiver. * info: Pointer to optional parameter according to event type: * - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write * more bytes than indicated by 'size' field and update 'size' if less bytes are * written. * - EVENT_UNDERRUN: unused. * - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining. * - EVENT_MARKER: pointer to an uin32_t containing the marker position in frames. * - EVENT_NEW_POS: pointer to an uin32_t containing the new position in frames. * - EVENT_BUFFER_END: unused. */ typedef void (*callback_t)(int event, void* user, void *info); /* Returns the minimum frame count required for the successful creation of * an AudioTrack object. * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - NO_INIT: audio server or audio hardware not initialized */ static status_t getMinFrameCount(int* frameCount, int streamType =-1, uint32_t sampleRate = 0); /* Constructs an uninitialized AudioTrack. No connection with * AudioFlinger takes place. */ AudioTrack(); /* Creates an audio track and registers it with AudioFlinger. * Once created, the track needs to be started before it can be used. * Unspecified values are set to the audio hardware's current * values. * * Parameters: * * streamType: Select the type of audio stream this track is attached to * (e.g. AudioSystem::MUSIC). * sampleRate: Track sampling rate in Hz. * format: Audio format (e.g AudioSystem::PCM_16_BIT for signed * 16 bits per sample). * channels: Channel mask: see AudioSystem::audio_channels. * frameCount: Total size of track PCM buffer in frames. This defines the * latency of the track. * flags: Reserved for future use. * cbf: Callback function. If not null, this function is called periodically * to request new PCM data. * notificationFrames: The callback function is called each time notificationFrames PCM * frames have been comsumed from track input buffer. * user Context for use by the callback receiver. */ AudioTrack( int streamType, uint32_t sampleRate = 0, int format = 0, int channels = 0, int frameCount = 0, uint32_t flags = 0, callback_t cbf = 0, void* user = 0, int notificationFrames = 0, int sessionId = 0); /* Creates an audio track and registers it with AudioFlinger. With this constructor, * The PCM data to be rendered by AudioTrack is passed in a shared memory buffer * identified by the argument sharedBuffer. This prototype is for static buffer playback. * PCM data must be present into memory before the AudioTrack is started. * The Write() and Flush() methods are not supported in this case. * It is recommented to pass a callback function to be notified of playback end by an * EVENT_UNDERRUN event. */ AudioTrack( int streamType, uint32_t sampleRate = 0, int format = 0, int channels = 0, const sp& sharedBuffer = 0, uint32_t flags = 0, callback_t cbf = 0, void* user = 0, int notificationFrames = 0, int sessionId = 0); /* Terminates the AudioTrack and unregisters it from AudioFlinger. * Also destroys all resources assotiated with the AudioTrack. */ ~AudioTrack(); /* Initialize an uninitialized AudioTrack. * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful intialization * - INVALID_OPERATION: AudioTrack is already intitialized * - BAD_VALUE: invalid parameter (channels, format, sampleRate...) * - NO_INIT: audio server or audio hardware not initialized * */ status_t set(int streamType =-1, uint32_t sampleRate = 0, int format = 0, int channels = 0, int frameCount = 0, uint32_t flags = 0, callback_t cbf = 0, void* user = 0, int notificationFrames = 0, const sp& sharedBuffer = 0, bool threadCanCallJava = false, int sessionId = 0); /* Result of constructing the AudioTrack. This must be checked * before using any AudioTrack API (except for set()), using * an uninitialized AudioTrack produces undefined results. * See set() method above for possible return codes. */ status_t initCheck() const; /* Returns this track's latency in milliseconds. * This includes the latency due to AudioTrack buffer size, AudioMixer (if any) * and audio hardware driver. */ uint32_t latency() const; /* getters, see constructor */ int streamType() const; int format() const; int channelCount() const; uint32_t frameCount() const; int frameSize() const; sp& sharedBuffer(); /* After it's created the track is not active. Call start() to * make it active. If set, the callback will start being called. */ void start(); /* Stop a track. If set, the callback will cease being called and * obtainBuffer returns STOPPED. Note that obtainBuffer() still works * and will fill up buffers until the pool is exhausted. */ void stop(); bool stopped() const; /* flush a stopped track. All pending buffers are discarded. * This function has no effect if the track is not stoped. */ void flush(); /* Pause a track. If set, the callback will cease being called and * obtainBuffer returns STOPPED. Note that obtainBuffer() still works * and will fill up buffers until the pool is exhausted. */ void pause(); /* mute or unmutes this track. * While mutted, the callback, if set, is still called. */ void mute(bool); bool muted() const; /* set volume for this track, mostly used for games' sound effects * left and right volumes. Levels must be <= 1.0. */ status_t setVolume(float left, float right); void getVolume(float* left, float* right); /* set the send level for this track. An auxiliary effect should be attached * to the track with attachEffect(). Level must be <= 1.0. */ status_t setAuxEffectSendLevel(float level); void getAuxEffectSendLevel(float* level); /* set sample rate for this track, mostly used for games' sound effects */ status_t setSampleRate(int sampleRate); uint32_t getSampleRate(); /* Enables looping and sets the start and end points of looping. * * Parameters: * * loopStart: loop start expressed as the number of PCM frames played since AudioTrack start. * loopEnd: loop end expressed as the number of PCM frames played since AudioTrack start. * loopCount: number of loops to execute. Calling setLoop() with loopCount == 0 cancels any pending or * active loop. loopCount = -1 means infinite looping. * * For proper operation the following condition must be respected: * (loopEnd-loopStart) <= framecount() */ status_t setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount); status_t getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount); /* Sets marker position. When playback reaches the number of frames specified, a callback with event * type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker notification * callback. * If the AudioTrack has been opened with no callback function associated, the operation will fail. * * Parameters: * * marker: marker position expressed in frames. * * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - INVALID_OPERATION: the AudioTrack has no callback installed. */ status_t setMarkerPosition(uint32_t marker); status_t getMarkerPosition(uint32_t *marker); /* Sets position update period. Every time the number of frames specified has been played, * a callback with event type EVENT_NEW_POS is called. * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification * callback. * If the AudioTrack has been opened with no callback function associated, the operation will fail. * * Parameters: * * updatePeriod: position update notification period expressed in frames. * * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - INVALID_OPERATION: the AudioTrack has no callback installed. */ status_t setPositionUpdatePeriod(uint32_t updatePeriod); status_t getPositionUpdatePeriod(uint32_t *updatePeriod); /* Sets playback head position within AudioTrack buffer. The new position is specified * in number of frames. * This method must be called with the AudioTrack in paused or stopped state. * Note that the actual position set is modulo the AudioTrack buffer size in frames. * Therefore using this method makes sense only when playing a "static" audio buffer * as opposed to streaming. * The getPosition() method on the other hand returns the total number of frames played since * playback start. * * Parameters: * * position: New playback head position within AudioTrack buffer. * * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - INVALID_OPERATION: the AudioTrack is not stopped. * - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer */ status_t setPosition(uint32_t position); status_t getPosition(uint32_t *position); /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids * rewriting the buffer before restarting playback after a stop. * This method must be called with the AudioTrack in paused or stopped state. * * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - INVALID_OPERATION: the AudioTrack is not stopped. */ status_t reload(); /* returns a handle on the audio output used by this AudioTrack. * * Parameters: * none. * * Returned value: * handle on audio hardware output */ audio_io_handle_t getOutput(); /* returns the unique ID associated to this track. * * Parameters: * none. * * Returned value: * AudioTrack ID. */ int getSessionId(); /* Attach track auxiliary output to specified effect. Used effectId = 0 * to detach track from effect. * * Parameters: * * effectId: effectId obtained from AudioEffect::id(). * * Returned status (from utils/Errors.h) can be: * - NO_ERROR: successful operation * - INVALID_OPERATION: the effect is not an auxiliary effect. * - BAD_VALUE: The specified effect ID is invalid */ status_t attachAuxEffect(int effectId); /* obtains a buffer of "frameCount" frames. The buffer must be * filled entirely. If the track is stopped, obtainBuffer() returns * STOPPED instead of NO_ERROR as long as there are buffers availlable, * at which point NO_MORE_BUFFERS is returned. * Buffers will be returned until the pool (buffercount()) * is exhausted, at which point obtainBuffer() will either block * or return WOULD_BLOCK depending on the value of the "blocking" * parameter. */ enum { NO_MORE_BUFFERS = 0x80000001, STOPPED = 1 }; status_t obtainBuffer(Buffer* audioBuffer, int32_t waitCount); void releaseBuffer(Buffer* audioBuffer); /* As a convenience we provide a write() interface to the audio buffer. * This is implemented on top of lockBuffer/unlockBuffer. For best * performance * */ ssize_t write(const void* buffer, size_t size); /* * Dumps the state of an audio track. */ status_t dump(int fd, const Vector& args) const; private: /* copying audio tracks is not allowed */ AudioTrack(const AudioTrack& other); AudioTrack& operator = (const AudioTrack& other); /* a small internal class to handle the callback */ class AudioTrackThread : public Thread { public: AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false); private: friend class AudioTrack; virtual bool threadLoop(); virtual status_t readyToRun(); virtual void onFirstRef(); AudioTrack& mReceiver; Mutex mLock; }; bool processAudioBuffer(const sp& thread); status_t createTrack(int streamType, uint32_t sampleRate, int format, int channelCount, int frameCount, uint32_t flags, const sp& sharedBuffer, audio_io_handle_t output, bool enforceFrameCount); sp mAudioTrack; sp mCblkMemory; sp mAudioTrackThread; float mVolume[2]; float mSendLevel; uint32_t mFrameCount; audio_track_cblk_t* mCblk; uint8_t mStreamType; uint8_t mFormat; uint8_t mChannelCount; uint8_t mMuted; uint32_t mChannels; status_t mStatus; uint32_t mLatency; volatile int32_t mActive; callback_t mCbf; void* mUserData; uint32_t mNotificationFramesReq; // requested number of frames between each notification callback uint32_t mNotificationFramesAct; // actual number of frames between each notification callback sp mSharedBuffer; int mLoopCount; uint32_t mRemainingFrames; uint32_t mMarkerPosition; bool mMarkerReached; uint32_t mNewPosition; uint32_t mUpdatePeriod; uint32_t mFlags; int mSessionId; int mAuxEffectId; }; }; // namespace android #endif // ANDROID_AUDIOTRACK_H