This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
Draft
This page is not complete.
The appendWindowStart property of the SourceBuffer interface controls the timestamp for the start of the append window, a timestamp range that can be used to filter what media data is appended to the SourceBuffer. Coded media frames with timestamps wthin this range will be appended, whereas those outside the range will be filtered out.
The default value of appendWindowStart is the presentation start time, which is the beginning time of the playable media.
Syntax
var myAppendWindowStart = sourceBuffer.appendWindowStart; sourceBuffer.appendWindowStart = 2.0;
Value
A double, indicating the start time of the append window, in seconds.
Errors
The following errors may be thrown when setting a new value for this property.
| Error | Explanation |
|---|---|
InvalidAccessError |
An attempt was made to set the value to less than 0, or a value greater than or equal to SourceBuffer.appendWindowEnd. |
InvalidStateError |
This SourceBuffer object is being updated (i.e. its SourceBuffer.updating property is currently true), or this SourceBuffer has been removed from the MediaSource. |
Example
TBD
Specifications
| Specification | Status | Comment |
|---|---|---|
| Media Source Extensions The definition of 'appendWindowStart' in that specification. |
Candidate Recommendation | Initial definition. |
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support | 23 | (Yes) | 25.0 (25.0)[1] 42.0 (42.0) |
11[2] | 15 | 8 |
| Feature | Android | Edge | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|
| Basic support | 4.4.4 | (Yes) |
No support |
No support | 11 | 30 | No support |
[1] Available after switching the about:config preference media.mediasource.enabled to true. In addition, support was limited to a whitelist of sites, for example YouTube, Netflix, and other popular streaming sites. The whitelist was removed and Media Source Extensions was enabled by default in 42+ for all sites.
[2] Only works on Windows 8+.