[ogg-dev] Header packet multiplicity

ogg.k.ogg.k at googlemail.com ogg.k.ogg.k at googlemail.com
Wed Feb 13 03:06:35 PST 2008

> It's nice if the first header is small, because it lets you find the
> beginning-of-stream (bos) packets for all the streams quickly,
> ideally within a single read buffer, so you can configure the decoder
> pipeline. Currently the bos headers we have for codecs in Ogg are all
> less than 100 bytes.

Same for me, all good here.

> Otherwise, I don't suppose it matters much. The other main
> recommendation is that all the headers go together at the beginning,
> with a page flush after the last one, so it's easy to (a) find them
> and (b) copy and paste them when you're doing editing.

OK, I was thinking of whether there would be a "generic" way of skipping
packets which would be used for various codecs (eg, the header packet
walking described for theora and vorbis, which would be quite a bit more
complicated for kate due to the extra headers).

> * Ogg requires some way to identify the codec from the first packet.
> * Likewise, and regardless of whether you're using Ogg, it's nice if
> other parameters that might be relevant to setting up a pipeline are
> easy to extract without a full parser: frame size for video codecs,
> number of channels for audio codecs, that sort of thing.

OK, so it looks like it's all fine, then.
Thanks for the info.

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