AW: [vorbis-dev] Vorbis RTP Internet Draft

[Tor-Einar Jarnbjo]

> -----Ursprungliche Nachricht-----
> Von: owner-vorbis-dev at xiph.org [mailto:owner-vorbis-dev at xiph.org]Im
> Auftrag von Phil Kerr
> Gesendet: Mittwoch, 8. Januar 2003 19:33
> An: vorbis-dev at xiph.org
> Betreff: Re: [vorbis-dev] Vorbis RTP Internet Draft
>
>
> This is certainly an option, but the IETF do seem to prefer this kind
> of data to be sent out-of-band hence the suggestion to use RTCP.
>
> For implementation it allows for the main process to go into a simple
> loop and just decode the Vorbis stream, the control thread can take
> care of everything else.
>
> But, are there any advantages in keeping this data in-band that we have
> not covered?

If the codebook list (or the identification header) changes during
transmission and it is sent to the client using RTPC, will the client then
be able to tell exactly which audio packet is the first to be using the new
information when being decoded? You write "just prior to the Vorbis
bitstream change", but as I see it, it would be impossible for the server to
be sure that the RTP and RTPC packets are received in the correct order by
the client.

One solution would be to send codebook and id header changes in-stream (a
disadvantage about this would be that the client may fail to receive the
data completely), another solution would be to add a field to the RTPC
packets with the sequence number of the first RTP packet for which the new
data should be valid. The last solution would also allow the new data to be
sent some time before the actual change is taken place, allowing the client
to request a resend before the changes take effect.

Tor

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