[Theora-dev] Resyncing cut streams...

Michael Smith mlrsmith at gmail.com
Wed Jan 5 22:40:32 PST 2005


On Wed, 5 Jan 2005 22:28:48 -0800, Ralph Giles <giles at xiph.org> wrote:
> On Thu, Jan 06, 2005 at 02:09:09PM +0800, illiminable wrote:
> 
> > All of which are poor solutions. The other issue is, how are we supposed to
> > tell the difference between a file of this kind that really does intend for
> > there to be a wait time at the start (ie for resyncing, where the video may
> > really not be intended to start for some amount of time to compensate for
> > the different granularitys of the audio and video), and one which looks
> > idenical but expects us to treat the start as really being the start
> > regardless of the granule pos.
> 
> Just to address this part, I think the only thing that makes any sense
> here is to assume the granuletime zeros of the two streams align. That's
> the reasonable assumption when you start playback of an uncut stream,
> and there's no reason to change that reference if there's a hole.
> 
>  -r

That's not neccesarily true, though, even for "normal" streams. A
vorbis stream, for instance, may have a logically non-zero initial
offset, which vorbis uses to indicate that the codec should discard
the first N samples of the packet (as part of the sample-precise
support vorbis has).

Mike


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