[Ffmpeg-devel] Re: integrating AVS decoding into MPlayer

Baptiste Coudurier baptiste.coudurier
Sun Jul 16 00:11:40 CEST 2006

Rich Felker wrote:
> On Sat, Jul 15, 2006 at 10:49:02PM +0200, Baptiste Coudurier wrote:
>> NUT system is the best one around. Still I persist to say that wraping
>> specs are needed, and even more for ambiguous codecs wraping formats,
>> and a fourcc for each codec recognized must be written in the specs,
>> that means standardized.
> Let's propose a compromise: additional information on the NUT website
> or with the spec that's labelled "informative" as opposed to
> "normative", clarifying what the general rules mean for particular
> codecs.

I totally agree. It will avoid fourcc collision which might occur
according to the specs. Even in AVI some codecs use different fourcc...
Im also thinking about DV, DVCPRO, DV50, DVCPRO100 which need a clearly
specified fourcc.

> What do you mean by timecodes? I assumed you meant timestamps but
> maybe something else like chapter info..?
> As for subtitles, the subtitle codec_id specifies the format of the
> data.

Many format supports Timecode track which defines the timing reference
not starting at 0 and reference GOP headers timecode in MPEG-2 for
example. They allows non contiguous timing, and some other features.

IMHO those tracks might need another stream identifier and some flags
like drop frame flag, negative (reverse playing).

>> I just read the specs again and I also do not see and decent standard to
>> pack extradata for specific codec. Just put the MOV atoms in NUT ?
> Extradata is a single binary data block whose format is specified by
> the codec. For most codecs its obvious what it should be. For Xiph
> codecs a 'supplemental codec spec' is needed, as has been discussed on
> the nut devel list.

For example QDM2 uses 2 atoms. It might be necessary to mention correct
and clean formating.

Btw all, sorry for all those points I am talking about now, Im just a
bit late and I really want to participate in NUT revolution to the
container world.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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