Android APIs
public final class

SyncParams

extends Object
java.lang.Object
   ↳ android.media.SyncParams

Class Overview

Structure for common A/V sync params. Used by MediaSync {link MediaSync#getSyncParams()} and {link MediaSync#setSyncParams(SyncParams)} to control A/V sync behavior.

audio adjust mode: select handling of audio track when changing playback speed due to sync.

sync source: select clock source for sync.

tolerance: specifies the amount of allowed playback rate change to keep media in sync with the sync source. The handling of this depends on the sync source, but must not be negative, and must be less than one.

frameRate: initial hint for video frame rate. Used when sync source is vsync. Negative values can be used to clear a previous hint.

Summary

Constants
int AUDIO_ADJUST_MODE_DEFAULT System will determine best handling of audio for playback rate adjustments.
int AUDIO_ADJUST_MODE_RESAMPLE Resample audio when playback rate must be adjusted.
int AUDIO_ADJUST_MODE_STRETCH Time stretch audio when playback rate must be adjusted.
int SYNC_SOURCE_AUDIO Use audio track for sync source.
int SYNC_SOURCE_DEFAULT Use the default sync source (default).
int SYNC_SOURCE_SYSTEM_CLOCK Use system monotonic clock for sync source.
int SYNC_SOURCE_VSYNC Use vsync as the sync source.
Public Constructors
SyncParams()
Public Methods
SyncParams allowDefaults()
Allows defaults to be returned for properties not set.
int getAudioAdjustMode()
Retrieves the audio adjust mode.
float getFrameRate()
Retrieves the video frame rate hint.
int getSyncSource()
Retrieves the sync source.
float getTolerance()
Retrieves the tolerance factor.
SyncParams setAudioAdjustMode(int audioAdjustMode)
Sets the audio adjust mode.
SyncParams setFrameRate(float frameRate)
Sets the video frame rate hint to be used.
SyncParams setSyncSource(int syncSource)
Sets the sync source.
SyncParams setTolerance(float tolerance)
Sets the tolerance.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int AUDIO_ADJUST_MODE_DEFAULT

Added in API level 23

System will determine best handling of audio for playback rate adjustments.

Used by default. This will make audio play faster or slower as required by the sync source without changing its pitch; however, system may fall back to some other method (e.g. change the pitch, or mute the audio) if time stretching is no longer supported for the playback rate.

Constant Value: 0 (0x00000000)

public static final int AUDIO_ADJUST_MODE_RESAMPLE

Added in API level 23

Resample audio when playback rate must be adjusted.

This will make audio play faster or slower as required by the sync source by changing its pitch (making it lower to play slower, and higher to play faster.)

Constant Value: 2 (0x00000002)

public static final int AUDIO_ADJUST_MODE_STRETCH

Added in API level 23

Time stretch audio when playback rate must be adjusted.

This will make audio play faster or slower as required by the sync source without changing its pitch, as long as it is supported for the playback rate.

Constant Value: 1 (0x00000001)

public static final int SYNC_SOURCE_AUDIO

Added in API level 23

Use audio track for sync source. This requires audio data and an audio track.

Constant Value: 2 (0x00000002)

public static final int SYNC_SOURCE_DEFAULT

Added in API level 23

Use the default sync source (default). If media has video, the sync renders to a surface that directly renders to a display, and tolerance is non zero (e.g. not less than 0.001) vsync source is used for clock source. Otherwise, if media has audio, audio track is used. Finally, if media has no audio, system clock is used.

Constant Value: 0 (0x00000000)

public static final int SYNC_SOURCE_SYSTEM_CLOCK

Added in API level 23

Use system monotonic clock for sync source.

See Also
Constant Value: 1 (0x00000001)

public static final int SYNC_SOURCE_VSYNC

Added in API level 23

Use vsync as the sync source. This requires video data and an output surface that directly renders to the display, e.g. SurfaceView

This mode allows smoother playback experience by adjusting the playback speed to match the vsync rate, e.g. playing 30fps content on a 59.94Hz display. When using this mode, the tolerance should be set to greater than 0 (e.g. at least 1/1000), so that the playback speed can actually be adjusted.

This mode can also be used to play 25fps content on a 60Hz display using a 2:3 pulldown (basically playing the content at 24fps), which results on better playback experience on most devices. In this case the tolerance should be at least (1/24).

Constant Value: 3 (0x00000003)

Public Constructors

public SyncParams ()

Added in API level 23

Public Methods

public SyncParams allowDefaults ()

Added in API level 23

Allows defaults to be returned for properties not set. Otherwise a IllegalArgumentException exception is raised when getting those properties which have defaults but have never been set.

Returns
  • this SyncParams instance.

public int getAudioAdjustMode ()

Added in API level 23

Retrieves the audio adjust mode.

Returns
  • audio adjust mode
Throws
IllegalStateException if the audio adjust mode is not set.

public float getFrameRate ()

Added in API level 23

Retrieves the video frame rate hint.

Returns
  • frame rate factor. A non-negative number representing the maximum deviation of the playback rate from the playback rate set. (abs(actual_rate - set_rate) / set_rate), or a negative number representing the desire to clear a previous hint using these params.
Throws
IllegalStateException if frame rate is not set.

public int getSyncSource ()

Added in API level 23

Retrieves the sync source.

Returns
  • sync source
Throws
IllegalStateException if the sync source is not set.

public float getTolerance ()

Added in API level 23

Retrieves the tolerance factor.

Returns
  • tolerance factor. A non-negative number representing the maximum deviation of the playback rate from the playback rate set. (abs(actual_rate - set_rate) / set_rate)
Throws
IllegalStateException if tolerance is not set.

public SyncParams setAudioAdjustMode (int audioAdjustMode)

Added in API level 23

Sets the audio adjust mode.

Returns
  • this SyncParams instance.

public SyncParams setFrameRate (float frameRate)

Added in API level 23

Sets the video frame rate hint to be used. By default the frame rate is unspecified.

Parameters
frameRate A non-negative number used as an initial hint on the video frame rate to be used when using vsync as the sync source. A negative number is used to clear a previous hint.
Returns
  • this SyncParams instance.

public SyncParams setSyncSource (int syncSource)

Added in API level 23

Sets the sync source.

Returns
  • this SyncParams instance.

public SyncParams setTolerance (float tolerance)

Added in API level 23

Sets the tolerance. The default tolerance is platform specific, but is never more than 1/24.

Parameters
tolerance A non-negative number representing the maximum deviation of the playback rate from the playback rate set. (abs(actual_rate - set_rate) / set_rate)
Returns
  • this SyncParams instance.
Throws
if the tolerance is negative, or not less than one