Class: shaka.media.Playhead

Constructor

new Playhead(video, manifest, config, startTimenullable, onSeek, onEvent)

Creates a Playhead, which manages the video's current time. The Playhead provides mechanisms for setting the presentation's start time, restricting seeking to valid time ranges, and stopping playback for startup and re- buffering.
Parameters:
Name Type Attributes Description
video HTMLMediaElement
manifest shakaExtern.Manifest
config shakaExtern.StreamingConfiguration
startTime number <nullable>
 The playhead's initial position in seconds. If null, defaults to the start of the presentation for VOD and the live-edge for live.
onSeek function() Called when the user agent seeks to a time within the presentation timeline.
onEvent function(!Event) Called when an event is raised to be sent to the application.
Implements:
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Members

(private) buffering_ :boolean

Type:
  • boolean
Source:

(private, nullable) config_ :shakaExtern.StreamingConfiguration

Type:
Source:

(private) didFireLargeGap_ :boolean

Type:
  • boolean
Source:

(private) earlySeekTimer_ :shaka.util.Timer

Used to batch up early seeks and delay until video.currentTime is updated.
Type:
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(private) eventManager_ :shaka.util.EventManager

Type:
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(private, nullable) gapJumpTimer_ :shaka.util.Timer

Type:
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(private) hadSegmentAppended_ :boolean

Type:
  • boolean
Source:

(private, nullable) manifest_ :shakaExtern.Manifest

Type:
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(private, nullable) onEvent_ :?function(!Event)

Type:
  • ?function(!Event)
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(private, nullable) onSeek_ :?function()

Type:
  • ?function()
Source:

(private) playbackRate_ :number

Type:
  • number
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(private) prevReadyState_ :number

Type:
  • number
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(private) stallCorrected_ :boolean

True if we have already flushed the pipeline at stallPlayheadTime_. Allows us to avoid flushing multiple times for the same stall.
Type:
  • boolean
Source:

(private) stallPlayheadTime_ :number

The playhead time where we think a stall occurred. When the ready state says we don't have enough data and the playhead stops too long, we assume we have stalled.
Type:
  • number
Source:

(private) stallWallTime_ :number

The wall-clock time (in milliseconds) that the stall occurred. This is used to ensure we don't flush the pipeline too often.
Type:
  • number
Source:

(private, nullable) startTime_ :number

The playhead's initial position in seconds, or null if it should automatically be calculated later.
Type:
  • number
Source:

(private, nullable) trickPlayTimer_ :shaka.util.Timer

Type:
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(private) video_ :HTMLMediaElement

Type:
  • HTMLMediaElement
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Methods

(private) clampSeekToDuration_(time) → {number}

Clamp seek times and playback start times so that we never seek to the presentation duration. Seeking to or starting at duration does not work consistently across browsers. TODO: Clean up and simplify Playhead. There are too many layers of, methods for, and conditions on timestamp adjustment.
Parameters:
Name Type Description
time number
Source:
See:
Returns:
The adjusted seek time.
Type
number

(private) clampTime_(time) → {number}

Clamps the given time to the segment availability window.
Parameters:
Name Type Description
time number The time in seconds.
Source:
Returns:
The clamped time in seconds.
Type
number

destroy() → (non-null) {Promise}

Destroys the object, releasing all resources and shutting down all operations. Returns a Promise which is resolved when destruction is complete. This Promise should never be rejected.
Implements:
Source:
Returns:
Type
Promise

getPlaybackRate() → {number}

Gets the current effective playback rate. This may be negative even if the browser does not directly support rewinding.
Source:
Returns:
Type
number

(private) getStartTime_() → {number}

Gets the playhead's initial position in seconds.
Source:
Returns:
Type
number

getTime() → {number}

Gets the playhead's current (logical) position.
Source:
Returns:
Type
number

(private) movePlayhead_(currentTime, targetTime)

Moves the playhead to the target time, triggering a call to onSeeking_().
Parameters:
Name Type Description
currentTime number
targetTime number
Source:

(private) onEarlySeek_()

Handles a 'timeupdate' event that occurs before metadata is loaded, which would indicate that the user is seeking. Note that a 'seeking' event will not fire before content is loaded. In this state, the playhead can only move as a result of a seek action, so timeupdate is a good choice.
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(private) onLoadedMetadata_()

Handles a 'loadedmetadata' event.
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(private) onPlaying_()

Handles a 'playing' event.
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(private) onPollGapJump_()

Called on a recurring timer to check for gaps in the media. This is also called in a 'waiting' event.
Source:

(private) onRateChange_()

Handles a 'ratechange' event.
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(private) onSeeking_()

Handles a 'seeking' event.
Source:

(private) onSeekingToStartTime_()

Handles the 'seeking' event from the initial jump to the start time (if there is one).
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onSegmentAppended()

Called when a segment is appended by StreamingEngine, but not when a clear is pending. This means StreamingEngine will continue buffering forward from what is buffered. So we know about any gaps before the start.
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(private) reposition_(currentTime) → {number}

Computes a new playhead position that's within the presentation timeline.
Parameters:
Name Type Description
currentTime number
Source:
Returns:
The time to reposition the playhead to.
Type
number

setBuffering(buffering)

Stops the playhead for buffering, or resumes the playhead after buffering.
Parameters:
Name Type Description
buffering boolean True to stop the playhead; false to allow it to continue.
Source:

setPlaybackRate(rate)

Sets the playback rate.
Parameters:
Name Type Description
rate number
Source:

setStartTime(startTime)

Adjust the start time. Used by Player to implement the streaming.startAtSegmentBoundary configuration.
Parameters:
Name Type Description
startTime number
Source: