[FFmpeg-devel] RTSP from Tv-card with ffmpeg (looking for developer) (Jacob Strømlund)

Luca Abeni lucabe72
Thu May 24 08:35:49 CEST 2007

Hi Jacob,

Jacob Str?mlund wrote:
> Hi,
> First of all it is important that the streaming is RTSP and not RTP since
> RTP is one way communication and RTSP i two way.
I suspect you are a little bit confused here... RTSP is a "control 
protocol" used to start a stream, stop it, receive information about the 
stream (the SDP), etc... The real streaming happens via RTP.
So, when you play an RTSP stream, you use RTSP for getting a description 
of the stream (the SDP file), and to start the stream. Then, you receive 
the stream via RTP.

RTP is usually over UDP, while RTSP is over TCP (maybe this is why you 
say that RTP is one way and RTSP is two way?), but you can also have RTP 
over TCP (embedding it in an HTTP stream, or in an RTSP stream, if I 
remember well).

> Yes Darwin is able to relay streams at least it is when we are speaking
> audio and i'm pretty sure the same is possible with video.
Yes, I know it is able to relay streams... The only problem is to 
produce a stream that DSS can happily relay. I have never read DSS 
documentation, so I do not know how to do it. But it can be done: see 
the test*ToDarwin tests in live555.

> We are working professional with mobile video streaming and we've tried
> several other solutions the only one able to do a part of this with no
> lipsync problem is ffmpeg therefore we are interested in putting money to
> this project if a ffmpeg developer is available.
I currently hack ffmpeg only in my spare time, so I cannot spend too 
much time on improving its RTP capabilities. We can discuss this 
offline, if you want.


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