[vlc-devel] VLC RTSP Server Support for Keep-Alive Messages to Kill Orphaned Streams?

Rémi Denis-Courmont remi at remlab.net
Wed Jul 15 22:11:06 CEST 2009

Le mercredi 15 juillet 2009 22:47:33 Robert Krakora, vous avez écrit :
> Again, thanks for the quick response.  May I inquire how then does the
> VLC RTSP server handle orphaned RTSP sessions?

RTSP sessions are not such a big deal. They just time out via normal TCP 
transport semantics. Similarly RTP over DCCP will time out through congestion 
control. RTP over UDP is never timing out, and that is a problem.

> How about a command line and GUI option that allows the minimum
> "keep-alive" functionality described in the RFC to be utilized (i.e.
> GET_PARAMETER and PLAY).  Of course the RTSP server would also have to
> convey the "keep-alive" timeout to the RTSP clients so that they know
> to send "keep-alives" and at what interval to send them.

No. IIRC, the keep-alive has a default value, and I see no strong reason to 
not follow the default, but that's not the real problem.

> Surprise
> removal of RTSP clients without TEARDOWNs being issued happens all the
> time with settop boxes in situations where they lose power (unplugged
> for instance) or are reset by users.

There is no "theoretical" problem. VLC just needs to reset the (would-be) 
timer when _either_ an RTSP request comes _or_ a valid RTCP-RR is received. 
When the timer fires, the RTP stream is dropped. Nobody has ever bothered to 
implement this.

Rémi Denis-Courmont

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