/*
* 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 <stdint.h>
#include <sys/types.h>
#include <media/IAudioFlinger.h>
#include <media/IAudioTrack.h>
#include <media/AudioSystem.h>
#include <utils/RefBase.h>
#include <utils/Errors.h>
#include <binder/IInterface.h>
#include <binder/IMemory.h>
#include <utils/threads.h>
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 format;
int channelCount; // will be removed in the future, do not use
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. AUDIO_STREAM_MUSIC).
* sampleRate: Track sampling rate in Hz.
* format: Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed
* 16 bits per sample).
* channelMask: Channel mask: see audio_channels_t.
* 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 channelMask = 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 channelMask = 0,
const sp<IMemory>& 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 channelMask = 0,
int frameCount = 0,
uint32_t flags = 0,
callback_t cbf = 0,
void* user = 0,
int notificationFrames = 0,
const sp<IMemory>& 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<IMemory>& 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 <position> 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<String16>& 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<AudioTrackThread>& thread);
status_t createTrack_l(int streamType,
uint32_t sampleRate,
uint32_t format,
uint32_t channelMask,
int frameCount,
uint32_t flags,
const sp<IMemory>& sharedBuffer,
audio_io_handle_t output,
bool enforceFrameCount);
void flush_l();
status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);
audio_io_handle_t getOutput_l();
status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart);
sp<IAudioTrack> mAudioTrack;
sp<IMemory> mCblkMemory;
sp<AudioTrackThread> mAudioTrackThread;
float mVolume[2];
float mSendLevel;
uint32_t mFrameCount;
audio_track_cblk_t* mCblk;
uint32_t mFormat;
uint8_t mStreamType;
uint8_t mChannelCount;
uint8_t mMuted;
uint8_t mReserved;
uint32_t mChannelMask;
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<IMemory> mSharedBuffer;
int mLoopCount;
uint32_t mRemainingFrames;
uint32_t mMarkerPosition;
bool mMarkerReached;
uint32_t mNewPosition;
uint32_t mUpdatePeriod;
bool mFlushed; // FIXME will be made obsolete by making flush() synchronous
uint32_t mFlags;
int mSessionId;
int mAuxEffectId;
Mutex mLock;
status_t mRestoreStatus;
};
}; // namespace android
#endif // ANDROID_AUDIOTRACK_H