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author | Glenn Kasten <gkasten@google.com> | 2011-12-14 16:56:31 -0800 |
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committer | Android (Google) Code Review <android-gerrit@google.com> | 2011-12-14 16:56:31 -0800 |
commit | da7923ac2932769e6d64508376a449c9dcd2889e (patch) | |
tree | 2bd291deca16fde48bcf5d1b1494c0531464cf64 | |
parent | 377d4ae5cbb5304d3bae11a511bd51e2c58db236 (diff) | |
parent | e5fb263a3625c0e6b4a9aefa86067bb9463dd06d (diff) | |
download | frameworks_base-da7923ac2932769e6d64508376a449c9dcd2889e.zip frameworks_base-da7923ac2932769e6d64508376a449c9dcd2889e.tar.gz frameworks_base-da7923ac2932769e6d64508376a449c9dcd2889e.tar.bz2 |
Merge "Audio C++ comments"
-rw-r--r-- | include/media/AudioTrack.h | 98 | ||||
-rw-r--r-- | include/media/IAudioTrack.h | 10 | ||||
-rw-r--r-- | include/private/media/AudioTrackShared.h | 4 | ||||
-rw-r--r-- | media/libmedia/AudioTrack.cpp | 2 | ||||
-rw-r--r-- | services/audioflinger/AudioFlinger.cpp | 4 | ||||
-rw-r--r-- | services/audioflinger/AudioMixer.h | 4 |
6 files changed, 59 insertions, 63 deletions
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h index cb3d833..b106042 100644 --- a/include/media/AudioTrack.h +++ b/include/media/AudioTrack.h @@ -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); diff --git a/include/media/IAudioTrack.h b/include/media/IAudioTrack.h index 47d530b..3fa2bf8 100644 --- a/include/media/IAudioTrack.h +++ b/include/media/IAudioTrack.h @@ -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; }; diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h index 20abd51..046d5e9 100644 --- a/include/private/media/AudioTrackShared.h +++ b/include/private/media/AudioTrackShared.h @@ -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; diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp index af713fb..05271bc 100644 --- a/media/libmedia/AudioTrack.cpp +++ b/media/libmedia/AudioTrack.cpp @@ -1,4 +1,4 @@ -/* //device/extlibs/pv/android/AudioTrack.cpp +/* frameworks/base/media/libmedia/AudioTrack.cpp ** ** Copyright 2007, The Android Open Source Project ** diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp index 2b4e415..4f8ef4b 100644 --- a/services/audioflinger/AudioFlinger.cpp +++ b/services/audioflinger/AudioFlinger.cpp @@ -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; diff --git a/services/audioflinger/AudioMixer.h b/services/audioflinger/AudioMixer.h index 75c9170..da9e2b5 100644 --- a/services/audioflinger/AudioMixer.h +++ b/services/audioflinger/AudioMixer.h @@ -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, |