[MPlayer-dev-eng] Re: MPlayer RTP Support

[Ross Finlayson]

>There is a tricky part in RealNetwork rtsp support.
>
>They are using RDT (Real Data Transport) instead of RTP

That's correct.  RealNetworks' servers use their own proprietary 'RDT' 
protocol (with proprietary challenge-response authentication) rather than 
(open standard) RTP, when delivering *RealAudio or RealVideo* data.  Note, 
however, they they still use RTP when delivering other types of data (such 
as MPEG audio/video).  So, open RTSP/RTP code (such as that implemented in 
the "LIVE.COM Streaming Media" libraries) can still be used to stream some 
kinds of data from RealNetworks servers.

Also, there are plenty of other RTSP servers out there (most notably, 
Apple's QuickTime (aka. "Darwin") Streaming Server) that use RTP 
exclusively, so RTSP support will still be useful for streaming from these 
servers.

>I heard about some applications that were able to save a RDT/RTSP
>stream to a file, so they probably found the meaning of those challenges key

The "Streambox VCR" program (a bootleg Windoze application, available in 
binary only, as far as I can tell) is able to stream and record 
RealNetworks RTSP/RDT streams, so the authors of this program have 
presumably figured out the secret.  In any case, I suspect that anyone who 
tries to work on this runs the risk of being set upon by RealNetworks' 
lawyers...

         Ross.