- From: <bugzilla@jessica.w3.org>
- Date: Mon, 23 Dec 2013 16:35:09 +0000
- To: public-html-admin@w3.org
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24161 Bug ID: 24161 Summary: <track> short duration cues fail to reach the application Product: HTML WG Version: unspecified Hardware: All OS: All Status: NEW Severity: normal Priority: P2 Component: HTML5 spec Assignee: dave.null@w3.org Reporter: david.lewis4@bbc.co.uk QA Contact: public-html-bugzilla@w3.org CC: mike@w3.org, public-html-admin@w3.org, public-html-wg-issue-tracking@w3.org Applications will typically access cues in a track by attaching a cuechange event handler which operates on the list of cues found in activeCues. This works well for most cues e.g. subtitles where the duration is likely to be at least a few seconds. Cues with a duration of less than 250ms may never appear in the activeCues list due to the way the time marches on algorithm (described in 4.7.10.8) operates. The algorithm is typically fired by the timeupdate event which in most browsers is every 250ms. Cues which start and end between two iterations will be "missed cues" and never appear in the activeCues list. To ensure all cues from a track would be fired, an application would have to do one of the following: Attach an enter/exit event to every cue with duration <250ms Inspect the full list of cues when cuechange is fired to check for missed cues. Use cues with a duration of >250ms. The problem has been highlighted by liaison from the HbbTV Association in relation to MPEG DASH stream events received by hybrid TV devices. Because of the media format and platform limitations the work-arounds listed above would be difficult to implement. Please see this mailing list post for further details: http://lists.w3.org/Archives/Public/public-inbandtracks/2013Dec/0005.html -- You are receiving this mail because: You are on the CC list for the bug.
Received on Monday, 23 December 2013 16:35:20 UTC