[Ffmpeg-devel] Shorten audio FourCC

Roberto Togni r_togni
Mon Oct 9 21:23:29 CEST 2006


On Mon, 9 Oct 2006 20:04:42 +0100 (BST)
M?ns Rullg?rd <mru at inprovide.com> wrote:

> 
> Diego Biurrun said:
> > Shorten audio is not yet supported by MPlayer since it lacks a FourCC in
> > libavformat/riff.c.  Now adding one would be easy, but the question is
> > which one to choose.  The obvious choice would be 'shn', but that's just
> > three characters.  So maybe 'shor' or 'shn '.
> >
> > Then again, in libavcodec/shorten.c is the following code snippet:
> >
> >   /* shorten signature */
> >   if (get_bits_long(&s->gb, 32) != bswap_32(ff_get_fourcc("ajkg"))) {
> >   av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
> >
> > Does 'ajkg' have any further relationship with Shorten?  Should it be
> > used as the FourCC?
> 
> RIFF files use 16-bit IDs for audio.  Adding a bogus 32-bit ID there to work
> around design limitations in mplayer is unacceptable IMO.
> 

MPlayer can happily work also with 16-bit identifiers. But FOURCCs are
used by most formats, and look "better" than a random 16-bit IDs.

Ciao,
 Roberto




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