[Ffmpeg-devel] 4XM audio codec_tag

Michael Niedermayer michaelni
Mon Nov 6 14:21:19 CET 2006


Hi

On Mon, Nov 06, 2006 at 12:17:20PM +0100, Baptiste Coudurier wrote:
[...]
> 
> >>>>>>> I would tend towards: better clutter the table a bit and support more
> >>>>>>> formats however rare than having a cleaner table.
> >>>>>> Again you've drifted from the question of sharing the codec ID table
> >>>>>> between unrelated formats, and treating the RIFF table as some kind of
> >>>>>> absolute reference.
> >>>>>>
> >>>>>> Just face the facts: formats use different tags to identify codecs, no
> >>>>>> matter how much you pretend that all of them use the RIFF values.  The
> >>>>>> only way to properly handle this is by using one codec tag table per
> >>>>>> format.  End of story.
> >>>>> i have no problem with one table per format, what i have a problem with
> >>>>> is that libav* would fail decoding a file if no match is found and that
> >>>>> it would leave the codec tag decission to the end user and not suggest
> >>>>> a default one if theres none in the one table for the target format
> >>>>>
> >>>>> if OTOH there is one table per format and a default fallback table then
> >>>>> thats something different with which iam fine
> >>>> A "fallback table" doesn't make any sense at all.  None.  Zero.  Nil.
> >>>> Either a format supports some particular codec, in which case its ID
> >>>> table will have an entry for that codec, or the codec is not
> >>>> supported, in which case failure is the only sensible option.
> >>>> "Suggesting" to use a tag from some other random format instead is
> >>>> utterly senseless.  Such behavior is what created the AVI mess in the
> >>>> first place.
> >>> avi is a generic container its supposed to be possible to store anything
> >>> in it (with a few exceptions)
> >>> the same is the case for mov, matroska and nut
> >>> there is nothing messy with that
> >> There is nothing messy about a container that can potentially be used
> >> with any codec.  The mess comes when people INSIST ON INVENTING THEIR
> >> OWN CODEC TAGS.  How the f*ck are others supposed to know what those
> >> tags mean if they are not included in some kind of official list?
> > 
> > uhm, look in the lists for avi and mov? and just read the tag, ohh well
> > is it so hard to guess that mpg1 is mpeg-1 video?
> > 
> 
> Now look at 'mp4s', we have to deal with avi fourcc cause someone stupid
> thought that putting avi fourcc was ok to do...

is that is the worst you can find?
mp4s is microsofts official fourcc for iso mpeg4 version 1 IIRC
so i would suspect that this is besides m4s2 the most official fourcc
for mpeg4 in avi
really not a good example for bad user invented tags in avi ...


[...]
-- 
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




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