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Merge "Audio C++ comments"

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This commit is contained in:
Glenn Kasten
2011-12-14 16:56:31 -08:00
committed by Android (Google) Code Review
parent 377d4ae5cb e5fb263a36
commit da7923ac29
6 changed files with 59 additions and 63 deletions
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98
include/media/AudioTrack.h
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@@ -75,15 +75,15 @@ public:
size_t size;
union {
void* raw;
short* i16;
int8_t* i8;
short* i16; // signed 16-bit
int8_t* i8; // unsigned 8-bit, offset by 0x80
};
};
/* 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.
* invokes the callback when a new buffer becomes available or an underrun condition occurs.
* Parameters:
*
* event: type of event notified (see enum AudioTrack::event_type).
@@ -94,8 +94,8 @@ public:
* 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_MARKER: pointer to an uint32_t containing the marker position in frames.
* - EVENT_NEW_POS: pointer to an uint32_t containing the new position in frames.
* - EVENT_BUFFER_END: unused.
*/
@@ -135,9 +135,10 @@ public:
* flags: Reserved for future use.
* cbf: Callback function. If not null, this function is called periodically
* to request new PCM data.
* user: Context for use by the callback receiver.
* 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.
* frames have been consumed from track input buffer.
* sessionId: Specific session ID, or zero to use default.
*/
AudioTrack( int streamType,
@@ -152,11 +153,11 @@ public:
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
* 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
* PCM data must be present in memory before the AudioTrack is started.
* The write() and flush() methods are not supported in this case.
* It is recommended to pass a callback function to be notified of playback end by an
* EVENT_UNDERRUN event.
*/
@@ -172,15 +173,15 @@ public:
int sessionId = 0);
/* Terminates the AudioTrack and unregisters it from AudioFlinger.
* Also destroys all resources assotiated with the AudioTrack.
* Also destroys all resources associated 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
* - NO_ERROR: successful initialization
* - INVALID_OPERATION: AudioTrack is already initialized
* - BAD_VALUE: invalid parameter (channels, format, sampleRate...)
* - NO_INIT: audio server or audio hardware not initialized
* */
@@ -199,13 +200,13 @@ public:
/* Result of constructing the AudioTrack. This must be checked
* before using any AudioTrack API (except for set()), using
* before using any AudioTrack API (except for set()), because 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.
/* Returns this track's estimated latency in milliseconds.
* This includes the latency due to AudioTrack buffer size, AudioMixer (if any)
* and audio hardware driver.
*/
@@ -233,8 +234,8 @@ public:
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.
/* Flush a stopped track. All pending buffers are discarded.
* This function has no effect if the track is not stopped.
*/
void flush();
@@ -244,26 +245,25 @@ public:
*/
void pause();
/* mute or unmutes this track.
* While mutted, the callback, if set, is still called.
/* Mute or unmute this track.
* While muted, 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.
/* Set volume for this track, mostly used for games' sound effects
* left and right volumes. Levels must be >= 0.0 and <= 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.
/* Set the send level for this track. An auxiliary effect should be attached
* to the track with attachEffect(). Level must be >= 0.0 and <= 1.0.
*/
status_t setAuxEffectSendLevel(float level);
void getAuxEffectSendLevel(float* level);
/* set sample rate for this track, mostly used for games' sound effects
/* Set sample rate for this track, mostly used for games' sound effects
*/
status_t setSampleRate(int sampleRate);
uint32_t getSampleRate();
@@ -274,8 +274,8 @@ public:
*
* 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.
* 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()
@@ -283,10 +283,9 @@ public:
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.
/* 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:
@@ -301,10 +300,10 @@ public:
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.
/* 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:
@@ -318,12 +317,11 @@ public:
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.
* 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
* 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.
@@ -335,12 +333,12 @@ public:
* 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
* - 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
/* 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.
*
@@ -350,7 +348,7 @@ public:
*/
status_t reload();
/* returns a handle on the audio output used by this AudioTrack.
/* Returns a handle on the audio output used by this AudioTrack.
*
* Parameters:
* none.
@@ -360,18 +358,17 @@ public:
*/
audio_io_handle_t getOutput();
/* returns the unique ID associated to this track.
/* Returns the unique session ID associated with this track.
*
* Parameters:
* none.
*
* Returned value:
* AudioTrack ID.
* AudioTrack session ID.
*/
int getSessionId();
/* Attach track auxiliary output to specified effect. Used effectId = 0
/* Attach track auxiliary output to specified effect. Use effectId = 0
* to detach track from effect.
*
* Parameters:
@@ -385,9 +382,9 @@ public:
*/
status_t attachAuxEffect(int effectId);
/* obtains a buffer of "frameCount" frames. The buffer must be
/* 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,
* STOPPED instead of NO_ERROR as long as there are buffers available,
* 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
@@ -403,10 +400,9 @@ public:
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
* performance use callbacks. Return actual number of bytes written.
*
*/
ssize_t write(const void* buffer, size_t size);

10
include/media/IAudioTrack.h
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@@ -46,13 +46,13 @@ public:
*/
virtual void stop() = 0;
/* flush a stopped track. All pending buffers are discarded.
* This function has no effect if the track is not stoped.
/* Flush a stopped track. All pending buffers are discarded.
* This function has no effect if the track is not stopped.
*/
virtual void flush() = 0;
/* mute or unmutes this track.
* While mutted, the callback, if set, is still called.
/* Mute or unmute this track.
* While muted, the callback, if set, is still called.
*/
virtual void mute(bool) = 0;
@@ -67,7 +67,7 @@ public:
*/
virtual status_t attachAuxEffect(int effectId) = 0;
/* get this tracks control block */
/* get this track's control block */
virtual sp<IMemory> getCblk() const = 0;
};

4
include/private/media/AudioTrackShared.h
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@@ -59,8 +59,8 @@ struct audio_track_cblk_t
// The data members are grouped so that members accessed frequently and in the same context
// are in the same line of data cache.
Mutex lock;
Condition cv;
Mutex lock; // sizeof(int)
Condition cv; // sizeof(int)
volatile uint32_t user;
volatile uint32_t server;
uint32_t userBase;

2
media/libmedia/AudioTrack.cpp
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@@ -1,4 +1,4 @@
/* //device/extlibs/pv/android/AudioTrack.cpp
/* frameworks/base/media/libmedia/AudioTrack.cpp
**
** Copyright 2007, The Android Open Source Project
**

4
services/audioflinger/AudioFlinger.cpp
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@@ -1000,7 +1000,7 @@ AudioFlinger::ThreadBase::~ThreadBase()
void AudioFlinger::ThreadBase::exit()
{
// keep a strong ref on ourself so that we wont get
// keep a strong ref on ourself so that we won't get
// destroyed in the middle of requestExitAndWait()
sp <ThreadBase> strongMe = this;
@@ -2345,7 +2345,7 @@ bool AudioFlinger::MixerThread::checkForNewParameters_l()
}
if (param.getInt(String8(AudioParameter::keyFrameCount), value) == NO_ERROR) {
// do not accept frame count changes if tracks are open as the track buffer
// size depends on frame count and correct behavior would not be garantied
// size depends on frame count and correct behavior would not be guaranteed
// if frame count is changed after track creation
if (!mTracks.isEmpty()) {
status = INVALID_OPERATION;

4
services/audioflinger/AudioMixer.h
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@@ -65,10 +65,10 @@ public:
FORMAT = 0x4001,
MAIN_BUFFER = 0x4002,
AUX_BUFFER = 0x4003,
// for TARGET RESAMPLE
// for target RESAMPLE
SAMPLE_RATE = 0x4100,
RESET = 0x4101,
// for TARGET VOLUME (8 channels max)
// for target RAMP_VOLUME and VOLUME (8 channels max)
VOLUME0 = 0x4200,
VOLUME1 = 0x4201,
AUXLEVEL = 0x4210,