Playback Time

dash.js exposes multiple API endpoints in the MediaPlayer class to query the current playback position and information about the DVR window. Examples for VoD and live playback are illustrated in the sections below.

All methods available via the player instance, as an example:

var video = document.querySelector('video');
var player = dashjs.MediaPlayer().create();
player.initialize(video, url, false);
var time = player.time();

VoD

API call	Description
time()	Returns the current playback time relative to playback start (usually 0).
time(periodId)	Returns the current playback time relative to the period specified in periodId.
duration()	Returns the total duration of the content.
getDvrWindow()	Returns the start, the end and the size of the DVR window. For VoD content all media segments are available. Consequently, the DVR windows spans over the whole duration of the content.

Live

API call	Description
time()	Returns the current playback time relative to playback start (availability start time).
time(periodId)	Returns the current playback time relative to the period specified in periodId.
timeAsUtc()	Returns the current playback time relative to midnight UTC, Jan 1 1970
timeInDvrWindow()	Returns the current playback time relative to the start of the DVR window.
duration()	Returns the size of the DVR window: DVRWindow.end - DVRWindow.start.
getDvrWindow()	Returns the start, startAsUtc, the end, endAsUtc and the size of the DVR window. For live content media segments become available over time.

Seeking

dash.js provides two API endpoints to change the current playback position, namely seek() and seekToPresentationTime(). Both methods are available via the MediaPlayer class. As an example:

var video = document.querySelector('video');
var player = dashjs.MediaPlayer().create();
player.initialize(video, url, false);
player.seek(10)

While the seek() method expects values relative to DVRWindow.start the seekToPresentationTime() works with absolute presentation timestamps. Two examples to illustrate this behavior are depicted in the sections below.

VoD

For VoD playback both seek() and seekToPresentationTime() work in the same way and can be used interchangeable. This is due to the fact the DVR window for VoD spans over the whole duration of the content.

Live

For live playback the seek() method expects values relative to the start of the DVR window. Internally DVRWindow.start is added to the provided value. The seekToPresentationTime() method uses absolute presentation timestamps.

As an example, the following two code snippets each trigger a seek 20 seconds behind the live edge.

seek()

var video = document.querySelector('video');
var player = dashjs.MediaPlayer().create();
player.initialize(video, url, false);
var duration = player.duration()
player.seek(duration - 20);

seekToPresentationTime()

var video = document.querySelector('video');
var player = dashjs.MediaPlayer().create();
player.initialize(video, url, false);
var dvrWindowEnd = player.getDvrWindow().end
player.seekToPresentationTime(dvrWindowEnd - 20);