DefaultLivePlaybackSpeedControl
@UnstableApi
public final class DefaultLivePlaybackSpeedControl implements LivePlaybackSpeedControl
A LivePlaybackSpeedControl that adjusts the playback speed using a proportional controller.
The control mechanism calculates the adjusted speed as 1.0 + proportionalControlFactor
x (currentLiveOffsetSec - targetLiveOffsetSec). Unit speed (1.0f) is used, if the
currentLiveOffsetSec is closer to targetLiveOffsetSec than the value set with setMaxLiveOffsetErrorMsForUnitSpeed.
The resulting speed is clamped to a minimum and maximum speed defined by the media, the fallback values set with setFallbackMinPlaybackSpeed and setFallbackMaxPlaybackSpeed or the minimum and maximum fallback default values.
When the player rebuffers, the target live offset is increased to adjust to the reduced network capabilities. The live playback speed control also keeps track of the minimum possible live offset to decrease the target live offset again if conditions improve. The minimum possible live offset is derived from the current offset and the duration of buffered media.
Summary
Nested types |
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public final class DefaultLivePlaybackSpeedControl.BuilderBuilder for a |
Constants |
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static final float |
The default maximum factor by which playback can be sped up that should be used if no maximum playback speed is defined by the media. |
static final float |
The default minimum factor by which playback can be sped up that should be used if no minimum playback speed is defined by the media. |
static final long |
The default maximum difference between the current live offset and the target live offset, in milliseconds, for which unit speed (1.0f) is used. |
static final float |
The default smoothing factor when smoothing the minimum possible live offset that can be achieved during playback. |
static final long |
The default |
static final float |
The default |
static final long |
The default increment applied to the target live offset each time the player is rebuffering, in milliseconds |
Public methods |
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float |
getAdjustedPlaybackSpeed(long liveOffsetUs, long bufferedDurationUs)Returns the adjusted playback speed in order get closer towards the |
long |
Returns the current target live offset, in microseconds, or |
void |
Notifies the live playback speed control that a rebuffer occurred. |
void |
setLiveConfiguration(MediaItem.LiveConfiguration liveConfiguration)Sets the live configuration defined by the media. |
void |
setTargetLiveOffsetOverrideUs(long liveOffsetUs)Sets the target live offset in microseconds that overrides the live offset |
Constants
DEFAULT_FALLBACK_MAX_PLAYBACK_SPEED
public static final float DEFAULT_FALLBACK_MAX_PLAYBACK_SPEED = 1.03f
The default maximum factor by which playback can be sped up that should be used if no maximum playback speed is defined by the media.
DEFAULT_FALLBACK_MIN_PLAYBACK_SPEED
public static final float DEFAULT_FALLBACK_MIN_PLAYBACK_SPEED = 0.97f
The default minimum factor by which playback can be sped up that should be used if no minimum playback speed is defined by the media.
DEFAULT_MAX_LIVE_OFFSET_ERROR_MS_FOR_UNIT_SPEED
public static final long DEFAULT_MAX_LIVE_OFFSET_ERROR_MS_FOR_UNIT_SPEED = 20
The default maximum difference between the current live offset and the target live offset, in milliseconds, for which unit speed (1.0f) is used.
DEFAULT_MIN_POSSIBLE_LIVE_OFFSET_SMOOTHING_FACTOR
public static final float DEFAULT_MIN_POSSIBLE_LIVE_OFFSET_SMOOTHING_FACTOR = 0.999f
The default smoothing factor when smoothing the minimum possible live offset that can be achieved during playback.
DEFAULT_MIN_UPDATE_INTERVAL_MS
public static final long DEFAULT_MIN_UPDATE_INTERVAL_MS = 1000
The default minimum interval between playback speed changes, in milliseconds.
DEFAULT_PROPORTIONAL_CONTROL_FACTOR
public static final float DEFAULT_PROPORTIONAL_CONTROL_FACTOR = 0.1f
The default proportional control factor used to adjust the playback speed.
DEFAULT_TARGET_LIVE_OFFSET_INCREMENT_ON_REBUFFER_MS
public static final long DEFAULT_TARGET_LIVE_OFFSET_INCREMENT_ON_REBUFFER_MS = 500
The default increment applied to the target live offset each time the player is rebuffering, in milliseconds
Public methods
getAdjustedPlaybackSpeed
public float getAdjustedPlaybackSpeed(long liveOffsetUs, long bufferedDurationUs)
Returns the adjusted playback speed in order get closer towards the target live offset.
| Parameters | |
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long liveOffsetUs |
The current live offset, in microseconds. |
long bufferedDurationUs |
The duration of media that's currently buffered, in microseconds. |
| Returns | |
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float |
The adjusted factor by which playback should be sped up. |
getTargetLiveOffsetUs
public long getTargetLiveOffsetUs()
Returns the current target live offset, in microseconds, or TIME_UNSET if no target live offset is defined for the current media.
notifyRebuffer
public void notifyRebuffer()
Notifies the live playback speed control that a rebuffer occurred.
A rebuffer is defined to be caused by buffer depletion rather than a user action. Hence this method is not called during initial buffering or when buffering as a result of a seek operation.
setLiveConfiguration
public void setLiveConfiguration(MediaItem.LiveConfiguration liveConfiguration)
Sets the live configuration defined by the media.
| Parameters | |
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MediaItem.LiveConfiguration liveConfiguration |
The |
setTargetLiveOffsetOverrideUs
public void setTargetLiveOffsetOverrideUs(long liveOffsetUs)
Sets the target live offset in microseconds that overrides the live offset configured by the media. Passing C.TIME_UNSET deletes a previous override.
If no target live offset is configured by setLiveConfiguration, this override has no effect.