public
class
AudioTrack
extends Object
implements
AudioRouting
java.lang.Object | |
↳ | android.media.AudioTrack |
The AudioTrack class manages and plays a single audio resource for Java applications.
It allows streaming of PCM audio buffers to the audio sink for playback. This is
achieved by "pushing" the data to the AudioTrack object using one of the
write(byte[], int, int)
, write(short[], int, int)
,
and write(float[], int, int, int)
methods.
An AudioTrack instance can operate under two modes: static or streaming.
In Streaming mode, the application writes a continuous stream of data to the AudioTrack, using
one of the write()
methods. These are blocking and return when the data has been
transferred from the Java layer to the native layer and queued for playback. The streaming
mode is most useful when playing blocks of audio data that for instance are:
Upon creation, an AudioTrack object initializes its associated audio buffer.
The size of this buffer, specified during the construction, determines how long an AudioTrack
can play before running out of data.
For an AudioTrack using the static mode, this size is the maximum size of the sound that can
be played from it.
For the streaming mode, data will be written to the audio sink in chunks of
sizes less than or equal to the total buffer size.
AudioTrack is not final and thus permits subclasses, but such use is not recommended.
Nested classes | |
---|---|
class |
AudioTrack.Builder
Builder class for |
interface |
AudioTrack.OnPlaybackPositionUpdateListener
Interface definition for a callback to be invoked when the playback head position of an AudioTrack has reached a notification marker or has increased by a certain period. |
interface |
AudioTrack.OnRoutingChangedListener
This interface was deprecated
in API level 24.
users should switch to the general purpose
|
Constants | |
---|---|
int |
ERROR
Denotes a generic operation failure. |
int |
ERROR_BAD_VALUE
Denotes a failure due to the use of an invalid value. |
int |
ERROR_DEAD_OBJECT
An error code indicating that the object reporting it is no longer valid and needs to be recreated. |
int |
ERROR_INVALID_OPERATION
Denotes a failure due to the improper use of a method. |
int |
MODE_STATIC
Creation mode where audio data is transferred from Java to the native layer only once before the audio starts playing. |
int |
MODE_STREAM
Creation mode where audio data is streamed from Java to the native layer as the audio is playing. |
int |
PLAYSTATE_PAUSED
indicates AudioTrack state is paused |
int |
PLAYSTATE_PLAYING
indicates AudioTrack state is playing |
int |
PLAYSTATE_STOPPED
indicates AudioTrack state is stopped |
int |
STATE_INITIALIZED
State of an AudioTrack that is ready to be used. |
int |
STATE_NO_STATIC_DATA
State of a successfully initialized AudioTrack that uses static data, but that hasn't received that data yet. |
int |
STATE_UNINITIALIZED
State of an AudioTrack that was not successfully initialized upon creation. |
int |
SUCCESS
Denotes a successful operation. |
int |
WRITE_BLOCKING
The write mode indicating the write operation will block until all data has been written,
to be used as the actual value of the writeMode parameter in
|
int |
WRITE_NON_BLOCKING
The write mode indicating the write operation will return immediately after
queuing as much audio data for playback as possible without blocking,
to be used as the actual value of the writeMode parameter in
|
Fields | |
---|---|
protected
AudioAttributes |
mAttributes
|
protected
float |
mAuxEffectSendLevel
|
protected
float |
mLeftVolume
|
protected
float |
mRightVolume
|
Public constructors | |
---|---|
AudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)
Class constructor. |
|
AudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode, int sessionId)
Class constructor with audio session. |
|
AudioTrack(AudioAttributes attributes, AudioFormat format, int bufferSizeInBytes, int mode, int sessionId)
Class constructor with |
Public methods | |
---|---|
void
|
addOnRoutingChangedListener(AudioTrack.OnRoutingChangedListener listener, Handler handler)
This method was deprecated
in API level 24.
users should switch to the general purpose
|
void
|
addOnRoutingChangedListener(AudioRouting.OnRoutingChangedListener listener, Handler handler)
Adds an |
int
|
attachAuxEffect(int effectId)
Attaches an auxiliary effect to the audio track. |
void
|
flush()
Flushes the audio data currently queued for playback. |
int
|
getAudioFormat()
Returns the configured audio data encoding. |
int
|
getAudioSessionId()
Returns the audio session ID. |
int
|
getBufferCapacityInFrames()
Returns the maximum size of the |
int
|
getBufferSizeInFrames()
Returns the effective size of the |
int
|
getChannelConfiguration()
Returns the configured channel position mask. |
int
|
getChannelCount()
Returns the configured number of channels. |
AudioFormat
|
getFormat()
Returns the configured |
static
float
|
getMaxVolume()
Returns the maximum gain value, which is greater than or equal to 1.0. |
static
int
|
getMinBufferSize(int sampleRateInHz, int channelConfig, int audioFormat)
Returns the estimated minimum buffer size required for an AudioTrack
object to be created in the |
static
float
|
getMinVolume()
Returns the minimum gain value, which is the constant 0.0. |
static
int
|
getNativeOutputSampleRate(int streamType)
Returns the output sample rate in Hz for the specified stream type. |
int
|
getNotificationMarkerPosition()
Returns marker position expressed in frames. |
int
|
getPlayState()
Returns the playback state of the AudioTrack instance. |
int
|
getPlaybackHeadPosition()
Returns the playback head position expressed in frames. |
PlaybackParams
|
getPlaybackParams()
Returns the current playback parameters. |
int
|
getPlaybackRate()
Returns the current playback sample rate rate in Hz. |
int
|
getPositionNotificationPeriod()
Returns the notification update period expressed in frames. |
AudioDeviceInfo
|
getPreferredDevice()
Returns the selected output specified by |
AudioDeviceInfo
|
getRoutedDevice()
Returns an |
int
|
getSampleRate()
Returns the configured audio source sample rate in Hz. |
int
|
getState()
Returns the state of the AudioTrack instance. |
int
|
getStreamType()
Returns the type of audio stream this AudioTrack is configured for. |
boolean
|
getTimestamp(AudioTimestamp timestamp)
Poll for a timestamp on demand. |
int
|
getUnderrunCount()
Returns the number of underrun occurrences in the application-level write buffer since the AudioTrack was created. |
void
|
pause()
Pauses the playback of the audio data. |
void
|
play()
Starts playing an AudioTrack. |
void
|
release()
Releases the native AudioTrack resources. |
int
|
reloadStaticData()
Sets the playback head position within the static buffer to zero, that is it rewinds to start of static buffer. |
void
|
removeOnRoutingChangedListener(AudioTrack.OnRoutingChangedListener listener)
This method was deprecated
in API level 24.
users should switch to the general purpose
|
void
|
removeOnRoutingChangedListener(AudioRouting.OnRoutingChangedListener listener)
Removes an |
int
|
setAuxEffectSendLevel(float level)
Sets the send level of the audio track to the attached auxiliary effect
|
int
|
setBufferSizeInFrames(int bufferSizeInFrames)
Limits the effective size of the |
int
|
setLoopPoints(int startInFrames, int endInFrames, int loopCount)
Sets the loop points and the loop count. |
int
|
setNotificationMarkerPosition(int markerInFrames)
Sets the position of the notification marker. |
int
|
setPlaybackHeadPosition(int positionInFrames)
Sets the playback head position within the static buffer. |
void
|
setPlaybackParams(PlaybackParams params)
Sets the playback parameters. |
void
|
setPlaybackPositionUpdateListener(AudioTrack.OnPlaybackPositionUpdateListener listener, Handler handler)
Sets the listener the AudioTrack notifies when a previously set marker is reached or for each periodic playback head position update. |
void
|
setPlaybackPositionUpdateListener(AudioTrack.OnPlaybackPositionUpdateListener listener)
Sets the listener the AudioTrack notifies when a previously set marker is reached or for each periodic playback head position update. |
int
|
setPlaybackRate(int sampleRateInHz)
Sets the playback sample rate for this track. |
int
|
setPositionNotificationPeriod(int periodInFrames)
Sets the period for the periodic notification event. |
boolean
|
setPreferredDevice(AudioDeviceInfo deviceInfo)
Specifies an audio device (via an |
int
|
setStereoVolume(float leftGain, float rightGain)
This method was deprecated
in API level 21.
Applications should use |
int
|
setVolume(float gain)
Sets the specified output gain value on all channels of this track. |
void
|
stop()
Stops playing the audio data. |
int
|
write(float[] audioData, int offsetInFloats, int sizeInFloats, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
int
|
write(short[] audioData, int offsetInShorts, int sizeInShorts)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
int
|
write(byte[] audioData, int offsetInBytes, int sizeInBytes)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
int
|
write(ByteBuffer audioData, int sizeInBytes, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
int
|
write(ByteBuffer audioData, int sizeInBytes, int writeMode, long timestamp)
Writes the audio data to the audio sink for playback in streaming mode on a HW_AV_SYNC track. |
int
|
write(short[] audioData, int offsetInShorts, int sizeInShorts, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
int
|
write(byte[] audioData, int offsetInBytes, int sizeInBytes, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). |
Protected methods | |
---|---|
void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
int
|
getNativeFrameCount()
This method was deprecated
in API level 19.
Use the identical public method |
void
|
setState(int state)
This method was deprecated in API level 19. Only accessible by subclasses, which are not recommended for AudioTrack. |
Inherited methods | |
---|---|
From
class
java.lang.Object
| |
From
interface
android.media.AudioRouting
|
int ERROR
Denotes a generic operation failure.
Constant Value: -1 (0xffffffff)
int ERROR_BAD_VALUE
Denotes a failure due to the use of an invalid value.
Constant Value: -2 (0xfffffffe)
int ERROR_DEAD_OBJECT
An error code indicating that the object reporting it is no longer valid and needs to be recreated.
Constant Value: -6 (0xfffffffa)
int ERROR_INVALID_OPERATION
Denotes a failure due to the improper use of a method.
Constant Value: -3 (0xfffffffd)
int MODE_STATIC
Creation mode where audio data is transferred from Java to the native layer only once before the audio starts playing.
Constant Value: 0 (0x00000000)
int MODE_STREAM
Creation mode where audio data is streamed from Java to the native layer as the audio is playing.
Constant Value: 1 (0x00000001)
int PLAYSTATE_PAUSED
indicates AudioTrack state is paused
Constant Value: 2 (0x00000002)
int PLAYSTATE_PLAYING
indicates AudioTrack state is playing
Constant Value: 3 (0x00000003)
int PLAYSTATE_STOPPED
indicates AudioTrack state is stopped
Constant Value: 1 (0x00000001)
int STATE_INITIALIZED
State of an AudioTrack that is ready to be used.
Constant Value: 1 (0x00000001)
int STATE_NO_STATIC_DATA
State of a successfully initialized AudioTrack that uses static data, but that hasn't received that data yet.
Constant Value: 2 (0x00000002)
int STATE_UNINITIALIZED
State of an AudioTrack that was not successfully initialized upon creation.
Constant Value: 0 (0x00000000)
int SUCCESS
Denotes a successful operation.
Constant Value: 0 (0x00000000)
int WRITE_BLOCKING
The write mode indicating the write operation will block until all data has been written,
to be used as the actual value of the writeMode parameter in
write(byte[], int, int, int)
, write(short[], int, int, int)
,
write(float[], int, int, int)
, write(ByteBuffer, int, int)
, and
write(ByteBuffer, int, int, long)
.
Constant Value: 0 (0x00000000)
int WRITE_NON_BLOCKING
The write mode indicating the write operation will return immediately after
queuing as much audio data for playback as possible without blocking,
to be used as the actual value of the writeMode parameter in
write(ByteBuffer, int, int)
, write(short[], int, int, int)
,
write(float[], int, int, int)
, write(ByteBuffer, int, int)
, and
write(ByteBuffer, int, int, long)
.
Constant Value: 1 (0x00000001)
float mAuxEffectSendLevel
float mLeftVolume
float mRightVolume
AudioTrack (int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)
Class constructor.
Parameters | |
---|---|
streamType |
int :
the type of the audio stream. See
STREAM_VOICE_CALL , STREAM_SYSTEM ,
STREAM_RING , STREAM_MUSIC ,
STREAM_ALARM , and STREAM_NOTIFICATION . |
sampleRateInHz |
int :
the initial source sample rate expressed in Hz.
SAMPLE_RATE_UNSPECIFIED means to use a route-dependent value
which is usually the sample rate of the sink.
getSampleRate() can be used to retrieve the actual sample rate chosen. |
channelConfig |
int :
describes the configuration of the audio channels.
See CHANNEL_OUT_MONO and
CHANNEL_OUT_STEREO |
audioFormat |
int :
the format in which the audio data is represented.
See ENCODING_PCM_16BIT ,
ENCODING_PCM_8BIT ,
and ENCODING_PCM_FLOAT . |
bufferSizeInBytes |
int :
the total size (in bytes) of the internal buffer where audio data is
read from for playback. This should be a nonzero multiple of the frame size in bytes.
If the track's creation mode is If the track's creation mode is |
mode |
int :
streaming or static buffer. See MODE_STATIC and MODE_STREAM |
Throws | |
---|---|
IllegalArgumentException |
AudioTrack (int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode, int sessionId)
Class constructor with audio session. Use this constructor when the AudioTrack must be
attached to a particular audio session. The primary use of the audio session ID is to
associate audio effects to a particular instance of AudioTrack: if an audio session ID
is provided when creating an AudioEffect, this effect will be applied only to audio tracks
and media players in the same session and not to the output mix.
When an AudioTrack is created without specifying a session, it will create its own session
which can be retrieved by calling the getAudioSessionId()
method.
If a non-zero session ID is provided, this AudioTrack will share effects attached to this
session
with all other media players or audio tracks in the same session, otherwise a new session
will be created for this track if none is supplied.
Parameters | |
---|---|
streamType |
int :
the type of the audio stream. See
STREAM_VOICE_CALL , STREAM_SYSTEM ,
STREAM_RING , STREAM_MUSIC ,
STREAM_ALARM , and STREAM_NOTIFICATION . |
sampleRateInHz |
int :
the initial source sample rate expressed in Hz.
SAMPLE_RATE_UNSPECIFIED means to use a route-dependent value
which is usually the sample rate of the sink. |
channelConfig |
int :
describes the configuration of the audio channels.
See CHANNEL_OUT_MONO and
CHANNEL_OUT_STEREO |
audioFormat |
int :
the format in which the audio data is represented.
See ENCODING_PCM_16BIT and
ENCODING_PCM_8BIT ,
and ENCODING_PCM_FLOAT . |
bufferSizeInBytes |
int :
the total size (in bytes) of the internal buffer where audio data is
read from for playback. This should be a nonzero multiple of the frame size in bytes.
If the track's creation mode is If the track's creation mode is |
mode |
int :
streaming or static buffer. See MODE_STATIC and MODE_STREAM |
sessionId |
int :
Id of audio session the AudioTrack must be attached to |
Throws | |
---|---|
IllegalArgumentException |
AudioTrack (AudioAttributes attributes, AudioFormat format, int bufferSizeInBytes, int mode, int sessionId)
Class constructor with AudioAttributes
and AudioFormat
.
Parameters | |
---|---|
attributes |
AudioAttributes :
a non-null AudioAttributes instance. |
format |
AudioFormat :
a non-null AudioFormat instance describing the format of the data
that will be played through this AudioTrack. See AudioFormat.Builder for
configuring the audio format parameters such as encoding, channel mask and sample rate. |
bufferSizeInBytes |
int :
the total size (in bytes) of the internal buffer where audio data is
read from for playback. This should be a nonzero multiple of the frame size in bytes.
If the track's creation mode is If the track's creation mode is |
mode |
int :
streaming or static buffer. See MODE_STATIC and MODE_STREAM . |
sessionId |
int :
ID of audio session the AudioTrack must be attached to, or
AUDIO_SESSION_ID_GENERATE if the session isn't known at construction
time. See also generateAudioSessionId() to obtain a session ID before
construction. |
Throws | |
---|---|
IllegalArgumentException |
void addOnRoutingChangedListener (AudioTrack.OnRoutingChangedListener listener, Handler handler)
This method was deprecated
in API level 24.
users should switch to the general purpose
AudioRouting.OnRoutingChangedListener
class instead.
Adds an AudioTrack.OnRoutingChangedListener
to receive notifications of routing changes
on this AudioTrack.
Parameters | |
---|---|
listener |
AudioTrack.OnRoutingChangedListener :
The AudioTrack.OnRoutingChangedListener interface to receive notifications
of rerouting events. |
handler |
Handler :
Specifies the Handler object for the thread on which to execute
the callback. If null , the Handler associated with the main
Looper will be used. |
void addOnRoutingChangedListener (AudioRouting.OnRoutingChangedListener listener, Handler handler)
Adds an AudioRouting.OnRoutingChangedListener
to receive notifications of routing
changes on this AudioTrack.
Parameters | |
---|---|
listener |
AudioRouting.OnRoutingChangedListener :
The AudioRouting.OnRoutingChangedListener interface to receive
notifications of rerouting events. |
handler |
Handler :
Specifies the Handler object for the thread on which to execute
the callback. If null , the Handler associated with the main
Looper will be used.
|
int attachAuxEffect (int effectId)
Attaches an auxiliary effect to the audio track. A typical auxiliary effect is a reverberation effect which can be applied on any sound source that directs a certain amount of its energy to this effect. This amount is defined by setAuxEffectSendLevel(). .
After creating an auxiliary effect (e.g.
EnvironmentalReverb
), retrieve its ID with
getId()
and use it when calling
this method to attach the audio track to the effect.
To detach the effect from the audio track, call this method with a null effect id.
Parameters | |
---|---|
effectId |
int :
system wide unique id of the effect to attach |
Returns | |
---|---|
int |
error code or success, see SUCCESS ,
ERROR_INVALID_OPERATION , ERROR_BAD_VALUE
|
See also:
void flush ()
Flushes the audio data currently queued for playback. Any data that has
been written but not yet presented will be discarded. No-op if not stopped or paused,
or if the track's creation mode is not MODE_STREAM
.
Note that although data written but not yet presented is discarded, there is no
guarantee that all of the buffer space formerly used by that data
is available for a subsequent write.
For example, a call to write(byte[], int, int)
with sizeInBytes
less than or equal to the total buffer size
may return a short actual transfer count.
int getAudioFormat ()
Returns the configured audio data encoding. See ENCODING_PCM_8BIT
,
ENCODING_PCM_16BIT
, and ENCODING_PCM_FLOAT
.
Returns | |
---|---|
int |
int getAudioSessionId ()
Returns the audio session ID.
Returns | |
---|---|
int |
the ID of the audio session this AudioTrack belongs to. |
int getBufferCapacityInFrames ()
Returns the maximum size of the AudioTrack
buffer in frames.
If the track's creation mode is MODE_STATIC
,
it is equal to the specified bufferSizeInBytes on construction, converted to frame units.
A static track's frame count will not change.
If the track's creation mode is MODE_STREAM
,
it is greater than or equal to the specified bufferSizeInBytes converted to frame units.
For streaming tracks, this value may be rounded up to a larger value if needed by
the target output sink, and
if the track is subsequently routed to a different output sink, the
frame count may enlarge to accommodate.
If the AudioTrack
encoding indicates compressed data,
e.g. ENCODING_AC3
, then the frame count returned is
the size of the AudioTrack
buffer in bytes.
See also getProperty(String)
for key
PROPERTY_OUTPUT_FRAMES_PER_BUFFER
.
Returns | |
---|---|
int |
maximum size in frames of the AudioTrack buffer. |
Throws | |
---|---|
IllegalStateException |
if track is not initialized. |
int getBufferSizeInFrames ()
Returns the effective size of the AudioTrack
buffer
that the application writes to.
This will be less than or equal to the result of
getBufferCapacityInFrames()
.
It will be equal if setBufferSizeInFrames(int)
has never been called.
If the track is subsequently routed to a different output sink, the buffer size and capacity may enlarge to accommodate.
If the AudioTrack
encoding indicates compressed data,
e.g. ENCODING_AC3
, then the frame count returned is
the size of the AudioTrack
buffer in bytes.
See also getProperty(String)
for key
PROPERTY_OUTPUT_FRAMES_PER_BUFFER
.
Returns | |
---|---|
int |
current size in frames of the AudioTrack buffer. |
Throws | |
---|---|
IllegalStateException |
if track is not initialized. |
int getChannelConfiguration ()
Returns the configured channel position mask.
For example, refer to CHANNEL_OUT_MONO
,
CHANNEL_OUT_STEREO
, CHANNEL_OUT_5POINT1
.
This method may return CHANNEL_INVALID
if
a channel index mask was used. Consider
getFormat()
instead, to obtain an AudioFormat
,
which contains both the channel position mask and the channel index mask.
Returns | |
---|---|
int |
int getChannelCount ()
Returns the configured number of channels.
Returns | |
---|---|
int |
AudioFormat getFormat ()
Returns the configured AudioTrack
format.
Returns | |
---|---|
AudioFormat |
an AudioFormat containing the
AudioTrack parameters at the time of configuration.
|
float getMaxVolume ()
Returns the maximum gain value, which is greater than or equal to 1.0. Gain values greater than the maximum will be clamped to the maximum.
The word "volume" in the API name is historical; this is actually a gain. expressed as a linear multiplier on sample values, where a maximum value of 1.0 corresponds to a gain of 0 dB (sample values left unmodified).
Returns | |
---|---|
float |
the maximum value, which is greater than or equal to 1.0. |
int getMinBufferSize (int sampleRateInHz, int channelConfig, int audioFormat)
Returns the estimated minimum buffer size required for an AudioTrack
object to be created in the MODE_STREAM
mode.
The size is an estimate because it does not consider either the route or the sink,
since neither is known yet. Note that this size doesn't
guarantee a smooth playback under load, and higher values should be chosen according to
the expected frequency at which the buffer will be refilled with additional data to play.
For example, if you intend to dynamically set the source sample rate of an AudioTrack
to a higher value than the initial source sample rate, be sure to configure the buffer size
based on the highest planned sample rate.
Parameters | |
---|---|
sampleRateInHz |
int :
the source sample rate expressed in Hz.
SAMPLE_RATE_UNSPECIFIED is not permitted. |
channelConfig |
int :
describes the configuration of the audio channels.
See CHANNEL_OUT_MONO and
CHANNEL_OUT_STEREO |
audioFormat |
int :
the format in which the audio data is represented.
See ENCODING_PCM_16BIT and
ENCODING_PCM_8BIT ,
and ENCODING_PCM_FLOAT . |
Returns | |
---|---|
int |
ERROR_BAD_VALUE if an invalid parameter was passed,
or ERROR if unable to query for output properties,
or the minimum buffer size expressed in bytes.
|
float getMinVolume ()
Returns the minimum gain value, which is the constant 0.0. Gain values less than 0.0 will be clamped to 0.0.
The word "volume" in the API name is historical; this is actually a linear gain.
Returns | |
---|---|
float |
the minimum value, which is the constant 0.0. |
int getNativeOutputSampleRate (int streamType)
Returns the output sample rate in Hz for the specified stream type.
Parameters | |
---|---|
streamType |
int
|
Returns | |
---|---|
int |
int getNotificationMarkerPosition ()
Returns marker position expressed in frames.
Returns | |
---|---|
int |
marker position in wrapping frame units similar to getPlaybackHeadPosition() ,
or zero if marker is disabled.
|
int getPlayState ()
Returns the playback state of the AudioTrack instance.
Returns | |
---|---|
int |
int getPlaybackHeadPosition ()
Returns the playback head position expressed in frames.
Though the "int" type is signed 32-bits, the value should be reinterpreted as if it is
unsigned 32-bits. That is, the next position after 0x7FFFFFFF is (int) 0x80000000.
This is a continuously advancing counter. It will wrap (overflow) periodically,
for example approximately once every 27:03:11 hours:minutes:seconds at 44.1 kHz.
It is reset to zero by flush()
, reloadStaticData()
, and stop()
.
If the track's creation mode is MODE_STATIC
, the return value indicates
the total number of frames played since reset,
not the current offset within the buffer.
Returns | |
---|---|
int |
PlaybackParams getPlaybackParams ()
Returns the current playback parameters.
See setPlaybackParams(PlaybackParams)
to set playback parameters
Returns | |
---|---|
PlaybackParams |
current PlaybackParams . |
Throws | |
---|---|
IllegalStateException |
if track is not initialized. |
int getPlaybackRate ()
Returns the current playback sample rate rate in Hz.
Returns | |
---|---|
int |
int getPositionNotificationPeriod ()
Returns the notification update period expressed in frames. Zero means that no position update notifications are being delivered.
Returns | |
---|---|
int |
AudioDeviceInfo getPreferredDevice ()
Returns the selected output specified by setPreferredDevice(AudioDeviceInfo)
. Note that this
is not guaranteed to correspond to the actual device being used for playback.
Returns | |
---|---|
AudioDeviceInfo |
AudioDeviceInfo getRoutedDevice ()
Returns an AudioDeviceInfo
identifying the current routing of this AudioTrack.
Note: The query is only valid if the AudioTrack is currently playing. If it is not,
getRoutedDevice()
will return null.
Returns | |
---|---|
AudioDeviceInfo |
int getSampleRate ()
Returns the configured audio source sample rate in Hz.
The initial source sample rate depends on the constructor parameters,
but the source sample rate may change if setPlaybackRate(int)
is called.
If the constructor had a specific sample rate, then the initial sink sample rate is that
value.
If the constructor had SAMPLE_RATE_UNSPECIFIED
,
then the initial sink sample rate is a route-dependent default value based on the source [sic].
Returns | |
---|---|
int |
int getState ()
Returns the state of the AudioTrack instance. This is useful after the AudioTrack instance has been created to check if it was initialized properly. This ensures that the appropriate resources have been acquired.
Returns | |
---|---|
int |
int getStreamType ()
Returns the type of audio stream this AudioTrack is configured for.
Compare the result against STREAM_VOICE_CALL
,
STREAM_SYSTEM
, STREAM_RING
,
STREAM_MUSIC
, STREAM_ALARM
,
STREAM_NOTIFICATION
, or STREAM_DTMF
.
Returns | |
---|---|
int |
boolean getTimestamp (AudioTimestamp timestamp)
Poll for a timestamp on demand.
If you need to track timestamps during initial warmup or after a routing or mode change, you should request a new timestamp periodically until the reported timestamps show that the frame position is advancing, or until it becomes clear that timestamps are unavailable for this route.
After the clock is advancing at a stable rate, query for a new timestamp approximately once every 10 seconds to once per minute. Calling this method more often is inefficient. It is also counter-productive to call this method more often than recommended, because the short-term differences between successive timestamp reports are not meaningful. If you need a high-resolution mapping between frame position and presentation time, consider implementing that at application level, based on low-resolution timestamps.
The audio data at the returned position may either already have been presented, or may have not yet been presented but is committed to be presented. It is not possible to request the time corresponding to a particular position, or to request the (fractional) position corresponding to a particular time. If you need such features, consider implementing them at application level.
Parameters | |
---|---|
timestamp |
AudioTimestamp :
a reference to a non-null AudioTimestamp instance allocated
and owned by caller. |
Returns | |
---|---|
boolean |
true if a timestamp is available, or false if no timestamp is available.
If a timestamp if available,
the AudioTimestamp instance is filled in with a position in frame units, together
with the estimated time when that frame was presented or is committed to
be presented.
In the case that no timestamp is available, any supplied instance is left unaltered.
A timestamp may be temporarily unavailable while the audio clock is stabilizing,
or during and immediately after a route change.
A timestamp is permanently unavailable for a given route if the route does not support
timestamps. In this case, the approximate frame position can be obtained
using getPlaybackHeadPosition() .
However, it may be useful to continue to query for
timestamps occasionally, to recover after a route change.
|
int getUnderrunCount ()
Returns the number of underrun occurrences in the application-level write buffer since the AudioTrack was created. An underrun occurs if the application does not write audio data quickly enough, causing the buffer to underflow and a potential audio glitch or pop.
Underruns are less likely when buffer sizes are large.
It may be possible to eliminate underruns by recreating the AudioTrack with
a larger buffer.
Or by using setBufferSizeInFrames(int)
to dynamically increase the
effective size of the buffer.
Returns | |
---|---|
int |
void pause ()
Pauses the playback of the audio data. Data that has not been played
back will not be discarded. Subsequent calls to play()
will play
this data back. See flush()
to discard this data.
Throws | |
---|---|
IllegalStateException |
void play ()
Starts playing an AudioTrack.
If track's creation mode is MODE_STATIC
, you must have called one of
the write methods (write(byte[], int, int)
, write(byte[], int, int, int)
,
write(short[], int, int)
, write(short[], int, int, int)
,
write(float[], int, int, int)
, or write(ByteBuffer, int, int)
) prior to
play().
If the mode is MODE_STREAM
, you can optionally prime the data path prior to
calling play(), by writing up to bufferSizeInBytes
(from constructor).
If you don't call write() first, or if you call write() but with an insufficient amount of
data, then the track will be in underrun state at play(). In this case,
playback will not actually start playing until the data path is filled to a
device-specific minimum level. This requirement for the path to be filled
to a minimum level is also true when resuming audio playback after calling stop().
Similarly the buffer will need to be filled up again after
the track underruns due to failure to call write() in a timely manner with sufficient data.
For portability, an application should prime the data path to the maximum allowed
by writing data until the write() method returns a short transfer count.
This allows play() to start immediately, and reduces the chance of underrun.
Throws | |
---|---|
IllegalStateException |
if the track isn't properly initialized |
int reloadStaticData ()
Sets the playback head position within the static buffer to zero,
that is it rewinds to start of static buffer.
The track must be stopped or paused, and
the track's creation mode must be MODE_STATIC
.
As of M
, also resets the value returned by
getPlaybackHeadPosition()
to zero.
For earlier API levels, the reset behavior is unspecified.
Use setPlaybackHeadPosition(int)
with a zero position
if the reset of getPlaybackHeadPosition()
is not needed.
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_BAD_VALUE ,
ERROR_INVALID_OPERATION
|
void removeOnRoutingChangedListener (AudioTrack.OnRoutingChangedListener listener)
This method was deprecated
in API level 24.
users should switch to the general purpose
AudioRouting.OnRoutingChangedListener
class instead.
Removes an AudioTrack.OnRoutingChangedListener
which has been previously added
to receive rerouting notifications.
Parameters | |
---|---|
listener |
AudioTrack.OnRoutingChangedListener :
The previously added AudioTrack.OnRoutingChangedListener interface to remove. |
void removeOnRoutingChangedListener (AudioRouting.OnRoutingChangedListener listener)
Removes an AudioRouting.OnRoutingChangedListener
which has been previously added
to receive rerouting notifications.
Parameters | |
---|---|
listener |
AudioRouting.OnRoutingChangedListener :
The previously added AudioRouting.OnRoutingChangedListener interface
to remove.
|
int setAuxEffectSendLevel (float level)
Sets the send level of the audio track to the attached auxiliary effect
attachAuxEffect(int)
. Effect levels
are clamped to the closed interval [0.0, max] where
max is the value of getMaxVolume()
.
A value of 0.0 results in no effect, and a value of 1.0 is full send.
By default the send level is 0.0f, so even if an effect is attached to the player this method must be called for the effect to be applied.
Note that the passed level value is a linear scalar. UI controls should be scaled logarithmically: the gain applied by audio framework ranges from -72dB to at least 0dB, so an appropriate conversion from linear UI input x to level is: x == 0 -> level = 0 0 < x <= R -> level = 10^(72*(x-R)/20/R)
Parameters | |
---|---|
level |
float :
linear send level |
Returns | |
---|---|
int |
error code or success, see SUCCESS ,
ERROR_INVALID_OPERATION , ERROR
|
int setBufferSizeInFrames (int bufferSizeInFrames)
Limits the effective size of the AudioTrack
buffer
that the application writes to.
A write to this AudioTrack will not fill the buffer beyond this limit. If a blocking write is used then the write will block until the data can fit within this limit.
Changing this limit modifies the latency associated with the buffer for this track. A smaller size will give lower latency but there may be more glitches due to buffer underruns.
The actual size used may not be equal to this requested size.
It will be limited to a valid range with a maximum of
getBufferCapacityInFrames()
.
It may also be adjusted slightly for internal reasons.
If bufferSizeInFrames is less than zero then ERROR_BAD_VALUE
will be returned.
This method is only supported for PCM audio. It is not supported for compressed audio tracks.
Parameters | |
---|---|
bufferSizeInFrames |
int :
requested buffer size in frames |
Returns | |
---|---|
int |
the actual buffer size in frames or an error code,
ERROR_BAD_VALUE , ERROR_INVALID_OPERATION |
Throws | |
---|---|
IllegalStateException |
if track is not initialized. |
int setLoopPoints (int startInFrames, int endInFrames, int loopCount)
Sets the loop points and the loop count. The loop can be infinite.
Similarly to setPlaybackHeadPosition,
the track must be stopped or paused for the loop points to be changed,
and must use the MODE_STATIC
mode.
Parameters | |
---|---|
startInFrames |
int :
loop start marker expressed in frames.
Zero corresponds to start of buffer.
The start marker must not be greater than or equal to the buffer size in frames, or negative. |
endInFrames |
int :
loop end marker expressed in frames.
The total buffer size in frames corresponds to end of buffer.
The end marker must not be greater than the buffer size in frames.
For looping, the end marker must not be less than or equal to the start marker,
but to disable looping
it is permitted for start marker, end marker, and loop count to all be 0.
If any input parameters are out of range, this method returns ERROR_BAD_VALUE .
If the loop period (endInFrames - startInFrames) is too small for the implementation to
support,
ERROR_BAD_VALUE is returned.
The loop range is the interval [startInFrames, endInFrames).
As of M , the position is left unchanged,
unless it is greater than or equal to the loop end marker, in which case
it is forced to the loop start marker.
For earlier API levels, the effect on position is unspecified. |
loopCount |
int :
the number of times the loop is looped; must be greater than or equal to -1.
A value of -1 means infinite looping, and 0 disables looping.
A value of positive N means to "loop" (go back) N times. For example,
a value of one means to play the region two times in total. |
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_BAD_VALUE ,
ERROR_INVALID_OPERATION
|
int setNotificationMarkerPosition (int markerInFrames)
Sets the position of the notification marker. At most one marker can be active.
Parameters | |
---|---|
markerInFrames |
int :
marker position in wrapping frame units similar to
getPlaybackHeadPosition() , or zero to disable the marker.
To set a marker at a position which would appear as zero due to wraparound,
a workaround is to use a non-zero position near zero, such as -1 or 1. |
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_BAD_VALUE ,
ERROR_INVALID_OPERATION
|
int setPlaybackHeadPosition (int positionInFrames)
Sets the playback head position within the static buffer.
The track must be stopped or paused for the position to be changed,
and must use the MODE_STATIC
mode.
Parameters | |
---|---|
positionInFrames |
int :
playback head position within buffer, expressed in frames.
Zero corresponds to start of buffer.
The position must not be greater than the buffer size in frames, or negative.
Though this method and getPlaybackHeadPosition() have similar names,
the position values have different meanings.
If looping is currently enabled and the new position is greater than or equal to the loop end marker, the behavior varies by API level: as of M ,
the looping is first disabled and then the position is set.
For earlier API levels, the behavior is unspecified. |
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_BAD_VALUE ,
ERROR_INVALID_OPERATION
|
void setPlaybackParams (PlaybackParams params)
Sets the playback parameters.
This method returns failure if it cannot apply the playback parameters.
One possible cause is that the parameters for speed or pitch are out of range.
Another possible cause is that the AudioTrack
is streaming
(see MODE_STREAM
) and the
buffer size is too small. For speeds greater than 1.0f, the AudioTrack
buffer
on configuration must be larger than the speed multiplied by the minimum size
getMinBufferSize(int, int, int)
) to allow proper playback.
Parameters | |
---|---|
params |
PlaybackParams :
see PlaybackParams . In particular,
speed, pitch, and audio mode should be set. |
Throws | |
---|---|
IllegalArgumentException |
if the parameters are invalid or not accepted. |
IllegalStateException |
if track is not initialized. |
void setPlaybackPositionUpdateListener (AudioTrack.OnPlaybackPositionUpdateListener listener, Handler handler)
Sets the listener the AudioTrack notifies when a previously set marker is reached or for each periodic playback head position update. Use this method to receive AudioTrack events in the Handler associated with another thread than the one in which you created the AudioTrack instance.
Parameters | |
---|---|
handler |
Handler :
the Handler that will receive the event notification messages.
|
void setPlaybackPositionUpdateListener (AudioTrack.OnPlaybackPositionUpdateListener listener)
Sets the listener the AudioTrack notifies when a previously set marker is reached or for each periodic playback head position update. Notifications will be received in the same thread as the one in which the AudioTrack instance was created.
int setPlaybackRate (int sampleRateInHz)
Sets the playback sample rate for this track. This sets the sampling rate at which
the audio data will be consumed and played back
(as set by the sampleRateInHz parameter in the
AudioTrack(int, int, int, int, int, int)
constructor),
not the original sampling rate of the
content. For example, setting it to half the sample rate of the content will cause the
playback to last twice as long, but will also result in a pitch shift down by one octave.
The valid sample rate range is from 1 Hz to twice the value returned by
getNativeOutputSampleRate(int)
.
Use setPlaybackParams(PlaybackParams)
for speed control.
This method may also be used to repurpose an existing AudioTrack
for playback of content of differing sample rate,
but with identical encoding and channel mask.
Parameters | |
---|---|
sampleRateInHz |
int :
the sample rate expressed in Hz |
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_BAD_VALUE ,
ERROR_INVALID_OPERATION
|
int setPositionNotificationPeriod (int periodInFrames)
Sets the period for the periodic notification event.
Parameters | |
---|---|
periodInFrames |
int :
update period expressed in frames.
Zero period means no position updates. A negative period is not allowed. |
Returns | |
---|---|
int |
error code or success, see SUCCESS , ERROR_INVALID_OPERATION
|
boolean setPreferredDevice (AudioDeviceInfo deviceInfo)
Specifies an audio device (via an AudioDeviceInfo
object) to route
the output from this AudioTrack.
Parameters | |
---|---|
deviceInfo |
AudioDeviceInfo :
The AudioDeviceInfo specifying the audio sink.
If deviceInfo is null, default routing is restored. |
Returns | |
---|---|
boolean |
true if succesful, false if the specified AudioDeviceInfo is non-null and
does not correspond to a valid audio output device.
|
int setStereoVolume (float leftGain, float rightGain)
This method was deprecated
in API level 21.
Applications should use setVolume(float)
instead, as it
more gracefully scales down to mono, and up to multi-channel content beyond stereo.
Sets the specified left and right output gain values on the AudioTrack.
Gain values are clamped to the closed interval [0.0, max] where
max is the value of getMaxVolume()
.
A value of 0.0 results in zero gain (silence), and
a value of 1.0 means unity gain (signal unchanged).
The default value is 1.0 meaning unity gain.
The word "volume" in the API name is historical; this is actually a linear gain.
Parameters | |
---|---|
leftGain |
float :
output gain for the left channel. |
rightGain |
float :
output gain for the right channel |
Returns | |
---|---|
int |
error code or success, see SUCCESS ,
ERROR_INVALID_OPERATION |
int setVolume (float gain)
Sets the specified output gain value on all channels of this track.
Gain values are clamped to the closed interval [0.0, max] where
max is the value of getMaxVolume()
.
A value of 0.0 results in zero gain (silence), and
a value of 1.0 means unity gain (signal unchanged).
The default value is 1.0 meaning unity gain.
This API is preferred over setStereoVolume(float, float)
, as it
more gracefully scales down to mono, and up to multi-channel content beyond stereo.
The word "volume" in the API name is historical; this is actually a linear gain.
Parameters | |
---|---|
gain |
float :
output gain for all channels. |
Returns | |
---|---|
int |
error code or success, see SUCCESS ,
ERROR_INVALID_OPERATION
|
void stop ()
Stops playing the audio data.
When used on an instance created in MODE_STREAM
mode, audio will stop playing
after the last buffer that was written has been played. For an immediate stop, use
pause()
, followed by flush()
to discard audio data that hasn't been played
back yet.
Throws | |
---|---|
IllegalStateException |
int write (float[] audioData, int offsetInFloats, int sizeInFloats, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode),
or copies audio data for later playback (static buffer mode).
The format specified in the AudioTrack constructor should be
ENCODING_PCM_FLOAT
to correspond to the data in the array.
In streaming mode, the blocking behavior depends on the write mode. If the write mode is
WRITE_BLOCKING
, the write will normally block until all the data has been enqueued
for playback, and will return a full transfer count. However, if the write mode is
WRITE_NON_BLOCKING
, or the track is stopped or paused on entry, or another thread
interrupts the write by calling stop or pause, or an I/O error
occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0, and the write mode is ignored. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
float :
the array that holds the data to write.
The implementation does not clip for sample values within the nominal range
[-1.0f, 1.0f], provided that all gains in the audio pipeline are
less than or equal to unity (1.0f), and in the absence of post-processing effects
that could add energy, such as reverb. For the convenience of applications
that compute samples using filters with non-unity gain,
sample values +3 dB beyond the nominal range are permitted.
However such values may eventually be limited or clipped, depending on various gains
and later processing in the audio path. Therefore applications are encouraged
to provide samples values within the nominal range. |
offsetInFloats |
int :
the offset, expressed as a number of floats,
in audioData where the data to write starts.
Must not be negative, or cause the data access to go out of bounds of the array. |
sizeInFloats |
int :
the number of floats to write in audioData after the offset.
Must not be negative, or cause the data access to go out of bounds of the array. |
writeMode |
int :
one of WRITE_BLOCKING , WRITE_NON_BLOCKING . It has no
effect in static mode.
With WRITE_BLOCKING , the write will block until all data has been written
to the audio sink.
With WRITE_NON_BLOCKING , the write will return immediately after
queuing as much audio data for playback as possible without blocking. |
Returns | |
---|---|
int |
zero or the positive number of floats that were written, or one of the following
error codes. The number of floats will be a multiple of the channel count not to
exceed sizeInFloats.
|
int write (short[] audioData, int offsetInShorts, int sizeInShorts)
Writes the audio data to the audio sink for playback (streaming mode),
or copies audio data for later playback (static buffer mode).
The format specified in the AudioTrack constructor should be
ENCODING_PCM_16BIT
to correspond to the data in the array.
In streaming mode, the write will normally block until all the data has been enqueued for playback, and will return a full transfer count. However, if the track is stopped or paused on entry, or another thread interrupts the write by calling stop or pause, or an I/O error occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
short :
the array that holds the data to play. |
offsetInShorts |
int :
the offset expressed in shorts in audioData where the data to play
starts.
Must not be negative, or cause the data access to go out of bounds of the array. |
sizeInShorts |
int :
the number of shorts to read in audioData after the offset.
Must not be negative, or cause the data access to go out of bounds of the array. |
Returns | |
---|---|
int |
zero or the positive number of shorts that were written, or one of the following
error codes. The number of shorts will be a multiple of the channel count not to
exceed sizeInShorts.
write(short[], int, int, int) with writeMode
set to WRITE_BLOCKING .
|
int write (byte[] audioData, int offsetInBytes, int sizeInBytes)
Writes the audio data to the audio sink for playback (streaming mode),
or copies audio data for later playback (static buffer mode).
The format specified in the AudioTrack constructor should be
ENCODING_PCM_8BIT
to correspond to the data in the array.
The format can be ENCODING_PCM_16BIT
, but this is deprecated.
In streaming mode, the write will normally block until all the data has been enqueued for playback, and will return a full transfer count. However, if the track is stopped or paused on entry, or another thread interrupts the write by calling stop or pause, or an I/O error occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
byte :
the array that holds the data to play. |
offsetInBytes |
int :
the offset expressed in bytes in audioData where the data to write
starts.
Must not be negative, or cause the data access to go out of bounds of the array. |
sizeInBytes |
int :
the number of bytes to write in audioData after the offset.
Must not be negative, or cause the data access to go out of bounds of the array. |
Returns | |
---|---|
int |
zero or the positive number of bytes that were written, or one of the following
error codes. The number of bytes will be a multiple of the frame size in bytes
not to exceed sizeInBytes.
write(byte[], int, int, int) with writeMode
set to WRITE_BLOCKING .
|
int write (ByteBuffer audioData, int sizeInBytes, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode), or copies audio data for later playback (static buffer mode). The audioData in ByteBuffer should match the format specified in the AudioTrack constructor.
In streaming mode, the blocking behavior depends on the write mode. If the write mode is
WRITE_BLOCKING
, the write will normally block until all the data has been enqueued
for playback, and will return a full transfer count. However, if the write mode is
WRITE_NON_BLOCKING
, or the track is stopped or paused on entry, or another thread
interrupts the write by calling stop or pause, or an I/O error
occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0, and the write mode is ignored. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
ByteBuffer :
the buffer that holds the data to write, starting at the position reported
by audioData.position() .
Note that upon return, the buffer position ( audioData.position() ) will
have been advanced to reflect the amount of data that was successfully written to
the AudioTrack. |
sizeInBytes |
int :
number of bytes to write. It is recommended but not enforced
that the number of bytes requested be a multiple of the frame size (sample size in
bytes multiplied by the channel count).
Note this may differ from audioData.remaining() , but cannot exceed it. |
writeMode |
int :
one of WRITE_BLOCKING , WRITE_NON_BLOCKING . It has no
effect in static mode.
With WRITE_BLOCKING , the write will block until all data has been written
to the audio sink.
With WRITE_NON_BLOCKING , the write will return immediately after
queuing as much audio data for playback as possible without blocking. |
Returns | |
---|---|
int |
zero or the positive number of bytes that were written, or one of the following
error codes.
|
int write (ByteBuffer audioData, int sizeInBytes, int writeMode, long timestamp)
Writes the audio data to the audio sink for playback in streaming mode on a HW_AV_SYNC track. The blocking behavior will depend on the write mode.
Parameters | |
---|---|
audioData |
ByteBuffer :
the buffer that holds the data to write, starting at the position reported
by audioData.position() .
Note that upon return, the buffer position ( audioData.position() ) will
have been advanced to reflect the amount of data that was successfully written to
the AudioTrack. |
sizeInBytes |
int :
number of bytes to write. It is recommended but not enforced
that the number of bytes requested be a multiple of the frame size (sample size in
bytes multiplied by the channel count).
Note this may differ from audioData.remaining() , but cannot exceed it. |
writeMode |
int :
one of WRITE_BLOCKING , WRITE_NON_BLOCKING .
With WRITE_BLOCKING , the write will block until all data has been written
to the audio sink.
With WRITE_NON_BLOCKING , the write will return immediately after
queuing as much audio data for playback as possible without blocking. |
timestamp |
long :
The timestamp of the first decodable audio frame in the provided audioData. |
Returns | |
---|---|
int |
zero or the positive number of bytes that were written, or one of the following
error codes.
|
int write (short[] audioData, int offsetInShorts, int sizeInShorts, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode),
or copies audio data for later playback (static buffer mode).
The format specified in the AudioTrack constructor should be
ENCODING_PCM_16BIT
to correspond to the data in the array.
In streaming mode, the blocking behavior depends on the write mode. If the write mode is
WRITE_BLOCKING
, the write will normally block until all the data has been enqueued
for playback, and will return a full transfer count. However, if the write mode is
WRITE_NON_BLOCKING
, or the track is stopped or paused on entry, or another thread
interrupts the write by calling stop or pause, or an I/O error
occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
short :
the array that holds the data to write. |
offsetInShorts |
int :
the offset expressed in shorts in audioData where the data to write
starts.
Must not be negative, or cause the data access to go out of bounds of the array. |
sizeInShorts |
int :
the number of shorts to read in audioData after the offset.
Must not be negative, or cause the data access to go out of bounds of the array. |
writeMode |
int :
one of WRITE_BLOCKING , WRITE_NON_BLOCKING . It has no
effect in static mode.
With WRITE_BLOCKING , the write will block until all data has been written
to the audio sink.
With WRITE_NON_BLOCKING , the write will return immediately after
queuing as much audio data for playback as possible without blocking. |
Returns | |
---|---|
int |
zero or the positive number of shorts that were written, or one of the following
error codes. The number of shorts will be a multiple of the channel count not to
exceed sizeInShorts.
|
int write (byte[] audioData, int offsetInBytes, int sizeInBytes, int writeMode)
Writes the audio data to the audio sink for playback (streaming mode),
or copies audio data for later playback (static buffer mode).
The format specified in the AudioTrack constructor should be
ENCODING_PCM_8BIT
to correspond to the data in the array.
The format can be ENCODING_PCM_16BIT
, but this is deprecated.
In streaming mode, the blocking behavior depends on the write mode. If the write mode is
WRITE_BLOCKING
, the write will normally block until all the data has been enqueued
for playback, and will return a full transfer count. However, if the write mode is
WRITE_NON_BLOCKING
, or the track is stopped or paused on entry, or another thread
interrupts the write by calling stop or pause, or an I/O error
occurs during the write, then the write may return a short transfer count.
In static buffer mode, copies the data to the buffer starting at offset 0, and the write mode is ignored. Note that the actual playback of this data might occur after this function returns.
Parameters | |
---|---|
audioData |
byte :
the array that holds the data to play. |
offsetInBytes |
int :
the offset expressed in bytes in audioData where the data to write
starts.
Must not be negative, or cause the data access to go out of bounds of the array. |
sizeInBytes |
int :
the number of bytes to write in audioData after the offset.
Must not be negative, or cause the data access to go out of bounds of the array. |
writeMode |
int :
one of WRITE_BLOCKING , WRITE_NON_BLOCKING . It has no
effect in static mode.
With WRITE_BLOCKING , the write will block until all data has been written
to the audio sink.
With WRITE_NON_BLOCKING , the write will return immediately after
queuing as much audio data for playback as possible without blocking. |
Returns | |
---|---|
int |
zero or the positive number of bytes that were written, or one of the following
error codes. The number of bytes will be a multiple of the frame size in bytes
not to exceed sizeInBytes.
|
void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize
method to dispose of
system resources or to perform other cleanup.
The general contract of finalize
is that it is invoked
if and when the JavaTM virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize
method may take any action, including
making this object available again to other threads; the usual purpose
of finalize
, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize
method of class Object
performs no
special action; it simply returns normally. Subclasses of
Object
may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize
method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize
method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize
method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize
method causes
the finalization of this object to be halted, but is otherwise
ignored.
int getNativeFrameCount ()
This method was deprecated
in API level 19.
Use the identical public method getBufferSizeInFrames()
instead.
Returns the frame count of the native AudioTrack
buffer.
Returns | |
---|---|
int |
current size in frames of the AudioTrack buffer. |
Throws | |
---|---|
|
IllegalStateException |
void setState (int state)
This method was deprecated
in API level 19.
Only accessible by subclasses, which are not recommended for AudioTrack.
Sets the initialization state of the instance. This method was originally intended to be used in an AudioTrack subclass constructor to set a subclass-specific post-initialization state. However, subclasses of AudioTrack are no longer recommended, so this method is obsolete.
Parameters | |
---|---|
state |
int :
the state of the AudioTrack instance |