[vorbis-dev] rtp payload format

[Roland Parviainen]

Jack Moffitt wrote:
> 
> http://www.xiph.org/ogg/vorbis/doc/draft-moffitt-vorbis-rtp-00.txt
> 
> This is the Internet-Draft I'll be submitting tomorrow and hopefully
> presenting at the March IETF meeting.
> 
> If you see anything major, let me know right away, I'll be submitting
> this in the morning.
> 
> jack.

> 5 Open Issues
>
>   To decode a Vorbis stream, a set of codebooks is required.  These
>   codebooks are allowed to change for each logical bitstream (for
>   example, for each song encoded in a radio stream).
>
>   A client connecting to a multicast RTP Vorbis session needs to get the
>   first set of codebooks in some manner.  These codebooks are typically
>   between 4 kilobytes and 8 kilobytes in size.
>

Doesn't it need to get any set of codebooks, not only the first one?
Even if the following codebooks are sent as normal vorbis packets,
packet loss have to be considered. One lost packet containing a part of
a codebook should not make the rest of the stream unusable. Some sort of
reliability is needed for the codebooks.

>   A final solution to how best to deliver the codebooks has not yet been
>   realized.  Here are the current proposals:
>
>   - Including the first set of codebooks in the SDP description
>   
>   - Broadcasting a codebook only stream as a second multicast Vorbis
>     stream
>
>   - Create some method of requesting the codebooks via RTCP

- Interleave the current codebook (and info and comments?)  among the
data packets?

//Roland Parviainen

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