[ogg-dev] chaining support

Conrad Parker conrad at metadecks.org
Sat Jun 20 09:27:25 PDT 2009

2009/6/20 Silvia Pfeiffer <silvia at silvia-pfeiffer.de>:
> I agree, this has been a huge problem - and in fact is a problem with
> html5 <video> more generally than ogg.
> How do you think that a chain identifier in skeleton will make it
> possible to have e.g. a single seek bar over a stream? Would it be n
> timelines or one?

I was thinking that it would be useful to identify sections that are
logically part of the same content.

eg. if you edit out some part of file A, and end up with the chain A1,
A3. Then after that you play file B, and after that you play some data
derived from file C.

You might end up with a chain sequence like A1, A3, B, C1, C2, C5.

Perhaps it would make sense to give a seek bar for (A1, A3), then
reset it for B, and reset it for (C1, C2, C5).

Does that make sense?

(Use cases would be useful here...)


> Cheers,
> Silvia.
> On Sat, Jun 20, 2009 at 10:52 AM, Conrad Parker<conrad at metadecks.org> wrote:
>> Hi,
>> An issue that's been cropping up recently is chaining support. We
>> discussed this a bit at FOMS 2008, and there are some open issues.
>> There was talk of making some skeleton-like metadata that spans chain
>> boundaries (or perhaps putting into skeleton a "chain identifier").
>> Other things that need to be specced out:
>>  * edits vs. playlists: how to distinguish between chains that have
>> come about by removing part of an existing file, vs. a sequence of
>> completely separate files
>>  * how to present a seek bar to the user for each kind of chain, ie.
>> one timeline for the entire sequence?
>> Perhaps all we need is a field in skeleton (could be a text
>> message-header field) for "sequence identifier", which identifies
>> chain sections which are part of the same edit.
>> Chain sections which are just a concatenation of files to play (eg.
>> output from icecast) would be distinguished by not having the same
>> sequence id, either by explicitly having different sequence ids or by
>> not having a sequence id at all (the current case).
>> Conrad.
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>> ogg-dev at xiph.org
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