[FFmpeg-devel] [PATCH] avformat/oggparseogm: sync avctx w/ codecpar

Chris Cunningham chcunningham at chromium.org
Sat Feb 16 00:56:18 EET 2019


On Mon, Feb 11, 2019 at 1:55 PM Chris Cunningham <chcunningham at chromium.org>
wrote:

> On Fri, Feb 8, 2019 at 2:37 PM Michael Niedermayer <michaelni at gmx.at>
> wrote:
>
>> ogg allows chaining streams when they have differing serial numbers
>> https://xiph.org/ogg/doc/oggstream.html
>>
>> i think ive seen actual files doing this
>>
>> ogg_replace_stream() might assign these into existing avstreams i think
>>
>
> If I'm reading this correctly, I think that should always happen at the
> boundary of a new ogg page, meaning it wouldn't rely on this multiple
> headers logic?
>
> I found the commit where this was introduced
>
> https://github.com/FFmpeg/FFmpeg/commit/81b743eb1026547270b88ac6a5cb451a3907ee94?diff=split
>
> With the description:
> This fixes some old ogm files that had the 3rd vorbis header after a data
> packet in another stream. This is invalid in ogg, but this change shouldn't
> affect the behaviour of any valid file.
>
> So, I don't think we're going to find spec text for this. No spec for OGM
> and committer indicates its not valid Ogg. I'm guessing we want to still
> support these ogm files?
>
>
Hey friends, just checking in on this discussion. Pls advise on findings
above.

>


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