[vorbis] Re: Website for Ogg/Vorbis support for MPEG4IP

[Akos Maroy]

Mark Hetherington wrote:
> Could you please tell me what is so important about rtp/rtsp? It seems to be 
> the big issue people have with icecast, that it does support rtp/rtsp, but 
> I'm yet to understand what makes it so useful (or much about it at all).

The main problem of streaming through TCP is that it is a reliable 
transport: if packets are not recieved at the other end, they are 
resent. But with streaming content, this is usually not desirable, 
especially with live content. Since what would be resent is out of date 
anyway, it's better that it is lost. Moreover, the amount of data sent 
gets built up, since on top the new streamed data, there is the data to 
be resent.

As a result, if the connection is unreliable, or cannot bear the width 
of the stream always, it is bound to break: in face of a glitch in the 
connection, there is more and more data sent then before, making things 
even worse. (I regularly get complaints from modem users, that a 24 kb/s 
stream always breaks for them.)

RTP / RTSP are protocols based on UDP. UDP is an unreliable transport: 
of something sent was lost, then that data is lost. For streaming live 
content, this is actually desirable, as you have to keep up with the 
pace of the stream.

What would be also very beneficial for icecast, is the implement 
peeling. This would enable easy downscaling of a stream if it turns out 
that the connection can not bear the full width of the stream.

Icecast currently streams through HTTP, which is a TCP based protocol.

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.