[Ffmpeg-devel] [PATCH] remove special nuv wav tags

[Michael Niedermayer]

Hi

On Sun, Nov 05, 2006 at 11:24:15PM +0000, M?ns Rullg?rd wrote:
> Baptiste Coudurier <baptiste.coudurier at smartjog.com> writes:
> 
> > Reimar D?ffinger wrote:
> >> Hello,
> >> On Sun, Nov 05, 2006 at 09:13:14PM +0000, M?ns Rullg?rd wrote:
> >>> Also, setting AVCodecContext.codec_tag in nuv.c seems a little
> >>> questionable, given that most of the code treats it as RIFF codec tag,
> >>> which it is not in this case.
> >> 
> >> Either codec_tag is supposed to be riff tags then it should be removed
> >> or it is supposed to avoid information loss when doing stream copy then
> >> this is the correct use IMO.
> >
> > codec_tag is not riff tag, mov sets it too, and seriously I don't see
> > why demuxer should not set it to what's in the container.
> 
> Well, I guess I'm OK with demuxers setting codec_tag to whatever value
> the format uses, on the odd chance that something has a use for that
> piece of information.  I still find it a little strange putting
> format-specific data in AVCodecContext.  Don't we usually try to
> separate codecs from containers?  Besides, the codec_id field is
> meaningless without knowing which format it came from.
> 
> > Now lavf exports CODEC_ID which is unique and accurate. That means that
> > applications using lavf should use CODEC_ID, not codec_tag.
> > codec_tag is NOT accurate NOR unique.
> 
> Yes, I've never found codec_id insufficient.

well, some files need the codec_tag for correctly decoding them, RTFS 
h263dec.c (fourcc XVIX or UMP4 for example)

also huffyuv need various random fields from the avi header for being
correctly decoded, i think you wont like that either but its needed
dropping huffyuv isnt ok ...

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
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