[streaming] Re: RTP over RTSP with vlc 0.8.1

[Torben Knerr]

Jean-Paul Saman wrote:

> Torben Knerr wrote:
>
>> Dear Jean-Paul,
>>
>>
>> Jean-Paul Saman wrote:
>>
>>> Torben Knerr wrote:
>>>
>>>> in version 0.8.2 beta2 i found the option to stream RTP over RTSP 
>>>> (TCP)
>>>> in the preferences ui. is this already possible with vlc 0.8.1 
>>>> through a
>>>> commandline option?
>>>
>>>
>>>
>>>
>>> There is no such thing as streaming RTP voer RTSP. RTSP is a VOD 
>>> protocol for controlling the streaming server, while RTP is a 
>>> streaming protocol designed to deliver the audio video data to the 
>>> client.
>>
>>
>>
>> i know it is possible to stream rtp over tcp (instead of udp), which 
>> is called rtp over rtsp afaik.
>
>
> You are wrong rtp != rtsp. Both protocols can use TCP as transport 
> protocol however.


i fully agree that rtp and rtsp are totally different :)

>
>> it's mostly useful for clients behind a firewall, where udp traffic 
>> is blocked, so they access the
>> stream via tcp.
>
>> i found the commandline switch --rtsp-tcp, but i think won't work, 
>> because
>> afaik --rtsp-tcp is used to tell vlc how it should receive a stream, 
>> and not how
>> it should send out a rtp stream...
>
>
> You are correct here. What you are looking for is using --rtp-tcp aka 
> RTP over TCP.

that's exactly what i'm looking for. i'm pretty sure that this is also 
called rtp over rtsp,
but i wouldn't bet on it. nevertheless, we both speak of the same 
principle..

>
>> my commandine looks like this now:
>> vlc -v "E:\movie.mpg" --aspect-ratio="1.2222222" --rtsp-tcp 
>> --sout="#transcode{vcodec=mp4v,vb=60,width=240,height=196,fps=10,acodec=mp4a,ab=20,channels=1,samplerate=22050}:rtp{dst=127.0.0.1,ttl=255,port-video=20000,port-audio=20002,sdp='file://C:/Program 
>> Files/Darwin Streaming Server/Movies/vlc.sdp'}" vlc:quit
>>
>> what i'm doing here is to send a transcoded file as an rtp stream to 
>> darwin streaming server,
>> which relays it to a client.
>> i monitored the rtp packets on the local loopback (because i'm 
>> sending rtp packets to darwin,
>> which resides on the same host), and i see that the rtp packets are 
>> sent over udp.
>
>
> You keep mixing up RTP and RTSP which are not the same.

didn't want to be confusing here.. what i didn't explain was that i 
found the --rtsp-tcp switch
on the vlc wiki 
(http://wiki.videolan.org/index.php/VLC_command-line_help), where it says
that it is used for "rtp over rtsp". so the name of this commandline 
option is a little misleading
in this case.. but as mr ross finlayson says, this option applies to 
streaming _clients_ only,
so it is not possible to send rtp over rtsp/tcp with this option.

>
> You are looking for rtp/tcp combination, which is not implemented in 
> VLC. We welcome any patches implementing this !

basically yes, but referring to mr finlayson's reply there is part of 
the rtsp rfc which specifies
sending rtp data encapsulated in rtsp packets. so i think it would be a 
little more work than
just using tcp as a transport protocol instead of udp (at least if you 
want to be spec compliant,
which i would prefer).

i would also love to see this feature in future versions of vlc, but i'm 
in doubt this will happen soon :(
there was a discussion in this list some time ago, where i requested 
better rtsp server support for
vlc (including rtcp, more control over sdp generation and so on..), but 
it didn't happen until now.

anyway, i would love to see at least "rtp over rtsp". i think this 
should be possible with not
that much effort, because the basics are already present. plz.. :-)

>
> Greetings,
> Jean-Paul Saman.
>
regards, torben

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