[FFmpeg-devel] [PATCH 2/2] lavf: Add function for accessing Matroska Codec <-> CodecID table

[Derek Buitenhuis]

On 30/05/2012 3:44 PM, Reimar Döffinger wrote:
> On Wed, May 30, 2012 at 02:53:00PM -0400, Derek Buitenhuis wrote:
>> On 30/05/2012 2:47 PM, Reimar Döffinger wrote:
>>> You didn't say for what purpose/why that would be useful.
>>
>> To enable users to use other demuxers than lavf (such as haali).
>>
>> It is currently not possible to do this without this table.
> 
> I don't really understand that. Or rather I have a suspicion,
> which makes this a bit of a problematic approach, see below.

What's not to understand? 

>> For a similar case, see:
>>
>> http://ffmpeg.org/doxygen/trunk/group__riff__fourcc.html
> 
> The reason for that is that almost every format has a AVI fourcc,
> thus it is suitable as a universal identifier to players like
> MPlayer that don't want to rely on CODEC_IDs, particularly since
> FFmpeg doesn't have one for each codec that exits.
> However that only works of course if all demuxers translate to
> a fourcc. That is not unreasonable, since all that want to work
> with DirectShow or at least VfW have to I think.
> The case where you need the mkv values seems to be the case where
> the demuxers just throw out container-specific identifiers.
> For that case I don't think this approach of one function returning
> one array is reasonable, because the only logical conclusion would be
> to have one such function for every single container that exists.
> So there should a more efficient API then, if it's no longer about
> supporting conversion from _one single_ common standard.

Nice writeup, but entirely wrong. Considering I'm the person who
got Anton to implement those functions in the first place, I'm
pretty sure I'm the one who is right here. :) They exist solely
to allow non-lavf demuxer to use lavc.