[whatwg] Tracks and cues

Ian Hickson ian at hixie.ch
Wed Oct 24 09:34:56 PDT 2012

On Wed, 24 Oct 2012, Cyril Concolato wrote:
> Le 10/18/2012 9:59 PM, Ian Hickson a écrit :
> > On Wed, 25 Jul 2012, Silvia Pfeiffer wrote:
> > >
> > > If we are very clear about what will be in the cues and that it will 
> > > always be just SVG, we could just create a @kind="svg".
> >
> > IMHO the idea of putting SVG in cues seems to somewhat miss the point. 
> > SVG already has a timeline, it already supports synchronisation with 
> > videos, it should just be used that way.
> Originally my request was to be able to use plain SVG content in a track 
> (not embedded in WebVTT) and let the browser handle rendering, 
> synchronization... This has many advantages, see the end of this post: 
> http://lists.w3.org/Archives/Public/public-whatwg-archive/2012Jul/0196.html 

I don't understand why SMIL isn't the solution:


I thought this was something SVG solved years ago.

> It was suggested to me to embed it in VTT as a workaround.

I do not think this makes sense.

> My use case is live (possibly adaptive) video streaming with subtitles. 
> The video content is fetched dynamically based on the time, the current 
> video program (movie vs. ad), and possibly adaptively depending on the 
> available bandwidth (see HLS, DASH, SmoothStreaming...). In that use 
> case, the subtitles also need to be fetched dynamically and spliced. You 
> can't change the <track> src attribute on the fly (just like you can't 
> for the <video> element) as this would reset all cues. You need to 
> append cues. It would be good to either have MSE cover that or as I 
> suggested above have a method to parse cue segments.

Fair enough.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
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