[Ffmpeg-devel] Shorten audio FourCC

[Michael Niedermayer]

Hi

On Fri, Oct 13, 2006 at 11:45:27AM +0200, Diego Biurrun wrote:
> On Fri, Oct 13, 2006 at 10:44:42AM +0200, Baptiste Coudurier wrote:
> > 
> > Diego Biurrun wrote:
> > > 
> > > I've committed shrn as ID and a FIXME comment that outlines the problem.
> > > Reimar and Roberto are with me on this and Michael as well if I
> > > understood his mail right.
> > > 
> > > Mans, please don't be angry, as soon as we have 16 bit IDs for all
> > > codecs we shall resolve this issue properly.
> > 
> > I was also against this.
> 
> Right.
> 
> > I bet this won't be fixed in a short time, since it is working now.
> 
> It will be fixed as soon as we have 16-bit IDs for all the missing
> formats.  Nobody had one for Shorten and making up an arbitrary one,
> hmmmm.
> 
> In any case we will need a more general framework in the future since
> some formats expect audio FourCCs, not TwoCCs, and we should be able to
> convert between the two ..

add a simple {int codec_id, int codec_tag} table to each (de)muxer, these
tables already exist anyway but they should get a pointer in AVIn/OutputFormat

that way a generic layer could easily
1. check if the AVCodecContext.codec_tag of the input stream is valid for the
   output with the same codec_id and if so set the output streams 
   AVCodecContext.codec_tag
2. if 1. failed then find any valid codec_tag for the codec_id
3. if 2. failed too and the user specified a low enough strict_std_compliance
   then try to find codec_tags from other similar containers

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is