Web/API/SourceBuffer/mode

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The mode property of the SourceBuffer interface controls whether media segments can be appended to the SourceBuffer in any order, or in a strict sequence.

The two available values are:

segments: The media segment timestamps determine the order in which the segments are played. The segments can be appended to the SourceBuffer in any order.
sequence: The order in which the segments are appended to the SourceBuffer determines the order in which they are played. Segment timestamps are generated automatically for the segments that observe this order.

The mode value is initially set when the SourceBuffer is created using MediaSource.addSourceBuffer(). If timestamps already exist for the media segments, then the value will be set to segments; if they don't, then the value will be set to sequence.

If you try to set the mode property value to segments when the initial value is sequence, an exception will be thrown. The existing segment order must be maintained in sequence mode. You can, however, change the value from segments to sequence. It just means the play order will be fixed, and new timestamps generated to reflect this.

This property cannot be changed during while the SourceBuffer is processing either an appendBuffer() or remove() call.

Syntax

var myMode = sourceBuffer.mode;

sourceBuffer.mode = 'sequence';

Value

A DOMString.

Exceptions

The following exceptions may be thrown when setting a new value for this property.

Exception	Explanation
`InvalidAccessError`	An attempt was made to set the value to `segments` when the initial value is `sequence`.
`InvalidStateError`	The `SourceBuffer` object is being updated (i.e. its `SourceBuffer.updating` property is currently `true`), the last media segment appended to this `SourceBuffer` is incomplete, or this `SourceBuffer` has been removed from the `MediaSource`.

Example

This snippet sets the sourceBuffer mode to 'sequence' if it is currently set to 'segments', thus setting the play order to the sequence in which media segments are appended.

var curMode = sourceBuffer.mode;
if (curMode == 'segments') {
  sourceBuffer.mode = 'sequence';
}

Specifications

Specification	Status	Comment
Media Source ExtensionsThe definition of 'mode' in that specification.	Recommendation	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`mode`	Chrome Full support 23	Edge Full support 12	Firefox Full support 42 Full support 42 No support 25 — 42 Notes' Disabled' Notes' Limited support to an allowed list of sites, for example YouTube, Netflix, and other popular streaming sites. The limitation was removed when Media Source Extensions was enabled by default in Firefox 42. Disabled' From version 25 until version 42 (exclusive): this feature is behind the `media.mediasource.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE Full support 11 Notes' Full support 11 Notes' Notes' Only works on Windows 8+.	Opera Full support 15	Safari Full support 8	WebView Android Full support 4.4.3	Chrome Android Full support 33	Firefox Android No support No	Opera Android Full support 14	Safari iOS No support No	Samsung Internet Android Full support 3.0

Legend

Full support: Full support
No support: No support
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.