Limited availability
Note: This feature is available in Dedicated Web Workers.
The SourceBuffer
interface represents a chunk of media to be passed into an HTMLMediaElement
and played, via a MediaSource
object. This can be made up of one or several media segments.
SourceBuffer.appendWindowEnd
Controls the timestamp for the end of the append window.
SourceBuffer.appendWindowStart
Controls the timestamp for the start of the append window. This is a timestamp range that can be used to filter what media data is appended to the SourceBuffer
. Coded media frames with timestamps within this range will be appended, whereas those outside the range will be filtered out.
SourceBuffer.audioTracks
Read only
A list of the audio tracks currently contained inside the SourceBuffer
.
SourceBuffer.buffered
Read only
Returns the time ranges that are currently buffered in the SourceBuffer
.
SourceBuffer.mode
Controls how the order of media segments in the SourceBuffer
is handled, in terms of whether they can be appended in any order, or they have to be kept in a strict sequence.
SourceBuffer.textTracks
Read only Experimental
A list of the text tracks currently contained inside the SourceBuffer
.
SourceBuffer.timestampOffset
Controls the offset applied to timestamps inside media segments that are subsequently appended to the SourceBuffer
.
SourceBuffer.updating
Read only
A boolean indicating whether the SourceBuffer
is currently being updated â i.e., whether an SourceBuffer.appendBuffer()
or SourceBuffer.remove()
operation is currently in progress.
SourceBuffer.videoTracks
Read only
A list of the video tracks currently contained inside the SourceBuffer
.
Inherits methods from its parent interface, EventTarget
.
SourceBuffer.abort()
Aborts the current segment and resets the segment parser.
SourceBuffer.appendBuffer()
Appends media segment data from an ArrayBuffer
, a TypedArray
or a DataView
object to the SourceBuffer
.
SourceBuffer.appendBufferAsync()
Non-standard Experimental
Starts the process of asynchronously appending the specified buffer to the SourceBuffer
. Returns a Promise
which is fulfilled once the buffer has been appended.
SourceBuffer.changeType()
Changes the MIME type that future calls to appendBuffer()
will expect the new data to conform to.
SourceBuffer.remove()
Removes media segments within a specific time range from the SourceBuffer
.
SourceBuffer.removeAsync()
Non-standard Experimental
Starts the process of asynchronously removing media segments in the specified range from the SourceBuffer
. Returns a Promise
which is fulfilled once all matching segments have been removed.
abort
Fired whenever SourceBuffer.appendBuffer()
is ended by a call to SourceBuffer.abort()
. SourceBuffer.updating
changes from true
to false
.
error
Fired whenever an error occurs during SourceBuffer.appendBuffer()
. SourceBuffer.updating
changes from true
to false
.
update
Fired whenever SourceBuffer.appendBuffer()
or SourceBuffer.remove()
completes. SourceBuffer.updating
changes from true
to false
. This event is fired before updateend
.
updateend
Fired after SourceBuffer.appendBuffer()
or SourceBuffer.remove()
ends. This event is fired after update
.
updatestart
Fired whenever the value of SourceBuffer.updating
changes from false
to true
.
The following example loads a video chunk by chunk as fast as possible, playing it as soon as it can.
You can see the complete code at https://github.com/mdn/dom-examples/tree/main/sourcebuffer and try the demo live at https://mdn.github.io/dom-examples/sourcebuffer/.
const video = document.querySelector("video");
const assetURL = "frag_bunny.mp4";
// Need to be specific for Blink regarding codecs
const mimeCodec = 'video/mp4; codecs="avc1.42E01E, mp4a.40.2"';
function loadVideo() {
if (MediaSource.isTypeSupported(mimeCodec)) {
const mediaSource = new MediaSource();
console.log(mediaSource.readyState); // closed
video.src = URL.createObjectURL(mediaSource);
mediaSource.addEventListener("sourceopen", sourceOpen);
} else {
console.error("Unsupported MIME type or codec: ", mimeCodec);
}
}
async function sourceOpen() {
console.log(this.readyState); // open
const sourceBuffer = this.addSourceBuffer(mimeCodec);
const response = await fetch(assetURL);
const buffer = await response.arrayBuffer();
sourceBuffer.addEventListener("updateend", () => {
this.endOfStream();
video.play();
console.log(this.readyState); // ended
});
sourceBuffer.appendBuffer(buffer);
}
const load = document.querySelector("#load");
load.addEventListener("click", loadVideo);
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HTML:
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| Version:
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