[FFmpeg-devel] [PATCH] RTSP multicast fix

Thijs Vermeir thijsvermeir
Thu Jul 12 21:59:54 CEST 2007


On 7/12/07, Luca Barbato <lu_zero at gentoo.org> wrote:
> Thijs Vermeir wrote:
> >> why is this needed?
> >
> > in the rfc that describes this SDP protocol [1] RTP/AVP/UDP is only
> > for unicast streams, RTP/AVP must be used for multicast streams. (also
> > in the examples in the RFC for RTSP [2] page 66)
> No
>    The syntax for the transport specifier is
>        transport/profile/lower-transport.
>    The default value for the "lower-transport" parameters is specific to
>    the profile. For RTP/AVP, the default is UDP.

Because a multicast can only be send over UDP this can be dropped
(like in the standard)

> > Now, the implementation is just wrong... it asks the stream from the
> Not really, it correctly falls back directly to unicast and the server
> should give an unicast rtsp session when requested...

Choosing for multicast is a client option. So the implementation is
wrong that it can't connect to a rtsp MULTICAST encoder. like in (
./ffplay rtsp:// )

> lu


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