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

[Baptiste Coudurier]

Hi

Michael Niedermayer wrote:
> [...]
> 
>>>> I persist to say that a container SHALL standardize a codec
>>>> wraping (even just saying "default wraping rule applies" and
>>>> its fourcc is ...) if it needs to support it. It should just be
>>>> a matter of one line per codec, as NUT is very generic ;)
>>> The one line would be the same for every codec so it's pointless.
>>> 
>> IMHO not for H264,
> 
> what exactly is unclear in the h.264 spec?

ISO/IEC specify bytestream NAL formating used in AVI.
1) Wraping in AVI IS NOT standardized.
2) Wraping in MOV IS standardized in ISO 14496-15.

Problem will occur with "stream copy" and reformating. Im just saying
that one way MUST be chosen, and clearly mentioned somewhere.

>>> What about timecode ? Subtitles ?
>> There is no specifications in NUT specs about wraping those kind of
>>  data. A stream type identifier is not sufficient IMHO.
>> 
>> 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 ?
> 
> which codec spec is unclear about how to store it? ogg based codecs
> yes, that needs a line to clarify

AAC, QDM2, ALAC, MP3, basically everything that uses an extradata IMHO.
Atm libavcodec assumes extradata is stored as MOV atoms. That is ugly
IMHO and making NUT to forbid those format is needed.

I think that we should mention wraping in order to be more specific and
avoid "blind" stream copy for those codecs.

For example, no extradata needed for AAC since it is stored as ADTS.
or AAC must be stored as frame and ADTS header as extradata.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
SMARTJOG S.A.                                    http://www.smartjog.com
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
Phone: +33 1 49966312