SourceBuffer: abort() method
The abort()
method of the SourceBuffer
interface aborts the current segment and resets the segment parser.
Syntax
js
abort()
Parameters
None.
Return value
None (undefined
).
Exceptions
InvalidStateError
DOMException
-
Thrown if the
MediaSource.readyState
property of the parent media source is not equal toopen
, or thisSourceBuffer
has been removed from theMediaSource
.
Examples
The spec description of abort()
is somewhat confusing — consider for
example step 1 of reset parser state. The MSE API is fully asynchronous, but this step seems to suggest a
synchronous (blocking) operation, which doesn't make sense.
Saying that, current implementations can be useful in certain situations, when you want to stop the current append (or whatever) operation occurring on a sourcebuffer, and then immediately start performing operations on it again. For example, consider this code:
js
sourceBuffer.addEventListener("updateend", (ev) => {
// ...
});
sourceBuffer.appendBuffer(buf);
Let's say that after the call to appendBuffer
BUT before the
updateend
event fires (i.e. a buffer is being appended but the operation
has not yet completed) a user "scrubs" the video seeking to a new point in time. In
this case you would want to manually call abort()
on the source buffer to
stop the decoding of the current buffer, then fetch and append the newly requested
segment that relates to the current new position of the video.
You can see something similar in action in Nick Desaulnier's bufferWhenNeeded demo — in line 48, an event listener is added to the playing video so a function called
seek()
is run when the seeking
event fires. In lines 92-101, the seek() function is defined — note that abort()
is called
if MediaSource.readyState
is set to open
, which means that
it is ready to receive new source buffers — at this point it is worth aborting the
current segment and just getting the one for the new seek position (see
checkBuffer()
and
getCurrentSegment()
.)
Specifications
Specification |
---|
Media Source Extensions™ # dom-sourcebuffer-abort |
Browser compatibility
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