[xiph-rtp] Re: [NUT-devel] Re: [theora-dev] Theora in Matroska

Ralph Giles giles at xiph.org
Fri Nov 3 16:28:22 PST 2006

On Fri, Nov 03, 2006 at 11:40:04PM +0100, Michael Niedermayer wrote:

> ive looked at the rtp draft and as far as i understand it it concatenates
> the first 2 packets and omits all further ones

First and 3rd packets, but yes. I missed that it's was omitting further 
ones in the draft review. It also uses a 16 bit length, with isn't 
general either. Using unary encoding like matroska and ogg does isn't
optimal for large packets either, of course. For RTP we were trying to 
keep it simple, and of course the RTP formats are by definition codec 
specific, so we didn't try to do anything like variable length length 

(I like the jpeg2k scheme, where the length header includes the bytes in 
the length header, so since the minimum length is greater than zero you 
have one or more bits to use as a flag to describe the width of the bits 
field. But a high-bit encoding like utf-8 works too.)

> this definitly has my support, not that that would make any difference... :)
> comments, userdata, and other non essential data does not belong to a global
> codec specific header be it in rtp or any container

The inline metadata helped solve a problem. Of course it's nice to use a 
container level metadata format if one is available, and in that case it 
should supercede the codec-level one. But the codec specs are very clear
that this header is required, even if it doesn't contain useful 
information. I think it's more confusing to treat this as a mistake and 
try to fix it.


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