[Ffmpeg-devel] global headers

[Måns Rullgård]

Michael Niedermayer <michaelni at gmx.at> writes:

> Hi
>
> On Sun, Mar 19, 2006 at 12:05:22AM +0000, M?ns Rullg?rd wrote:
>> Michael Niedermayer <michaelni at gmx.at> writes:
>> 
>> > could we use the same format and convert the global one in the mov/mp4
>> > (de)muxer?
>> 
>> We're doing the opposite right now.  I don't like this, since
>> whichever way it's done, several muxers will need to do the
>> conversion.  E.g. ADTS format is required for raw ADTS, MPEG-TS and
>> MPEG-PS.  MP4 requires the other format.  Matroska, as is to be
>> expected, uses it's own bastardized variant.
>
> fine, so what do you suggest? demuxer -> muxer must work even if the
> AAC variants differ ...
>
> so if a demuxer has ADTS internally what should be done, remove ADTS
> headers in the demuxer? in a middle layer? or the muxer?
>
> should it be optional or always be removed?
> always will break if the headers change (switching channels, movies, ...)
> allowed or not it will happen and must be supported

To me, the cleanest solution would be a middle layer for transforming
between the different formats.  Doing it in the demuxer or muxer will
inevitably lead to the same work being done in multiple places.

Could we perhaps use AVCodecContext.sub_id here?

-- 
M?ns Rullg?rd
mru at inprovide.com