Need to implement updated media timeline support




Audio/Video: Playback
8 years ago
2 years ago


(Reporter: cajbir, Unassigned)



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Firefox Tracking Flags

(Not tracked)





8 years ago
The WHATWG specification has changed to add a 'startTime' attribute to the MediaElement. This needs to be implemented.
Duplicate of this bug: 521899
We're out of date with the current HTML video spec. The timeline (i.e. the
values of HTMLMediaElement.currentTime) of a video/audio should go from the
"earliest possible position" to the las possible position. We currently always
have the playback position starting a 0 and ending at duration.
This seems like a somewhat unfortunate thing for the spec, I bet everyone's going to get it wrong because it won't be common. :( I can't help but wonder if it would be better to have a startTimeOffset property, so that .currentTime et al are all still have a timeline starting from 0, and if you want the "real" time you'd use .currentTime + .startTimeOffset.

I'd also suspect we'll want the default video controls to normalize everything to 0 (.currentTime - .startTime), since it would be really confusing otherwise.
I totally agree with comment #3.
Duplicate of this bug: 503802
Duplicate of this bug: 566375
When this bug is fixed, the following test should pass:
(Note that the tests current sniff the user agent for Firefox--hopefully that'll be fixed soon.)


7 years ago
Duplicate of this bug: 589565


7 years ago
Blocks: 554013
Keywords: html5

Comment 9

7 years ago
ietestcenter url:
Duplicate of this bug: 603034
Spec changed again, morphing this bug to track the current state.
Summary: HTMLMediaElement needs startTime attribute to be implemented → Need to implement updated media timeline (initialTime, startOffsetTime) support
Duplicate of this bug: 635569

Comment 13

6 years ago
Any new developments here?

Comment 14

6 years ago
I'd be reluctant to start implementing this part of the spec until things like multitrack, media controller, streams, etc are less of a moving target. It's likely to be in a bit of flux.

Comment 15

6 years ago
I'm adding 'initialTime' as part of the implementation of temporal media fragments in bug 648595.
Depends on: 648595

Comment 16

6 years ago
I recently did some experimental work on synchronising events to live streams, and I patched Firefox to implement startOffsetTime for WebM streams.

I do agree that the spec needs some clarification. My colleague Sean O'Halpin blogged about this:
Keywords: dev-doc-needed
Summary: Need to implement updated media timeline (initialTime, startOffsetTime) support → Need to implement updated media timeline support

Comment 17

4 years ago
It's been some time and I guess the spec has stabilized. If there are still outstandind issues, did anybody file bugs?
Component: Audio/Video → Audio/Video: Playback
This is no longer a requirement of the spec.
Last Resolved: 2 years ago
Resolution: --- → INVALID
Keywords: dev-doc-needed
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