[Live-devel] WMS RTSP support for VLC

[Derk-Jan Hartman]

Laurent Aimar (and I) spent an evening investigating how the Windows 
Media Server 9 RTSP server works. We discovered that even though the 
RTSP has several proprietary extensions, it is actually mostly valid 
RTSP and accepted by liveMedia. (wow, it works better than Real 
already)

After spending an hour with ethereal I found this on the net
http://www.soi.wide.ad.jp/class/20030038/slides/17/index_63.html
Which already had the ethereal captures. (ah well :)

Several things of importance. After this:
a=pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64
Follows the asf header in base64 encoding.

a=rtpmap:96 x-asf-pf/1000 is the type in use for WMV8 and WMA at least.
a=rtpmap:96 x-wms-rtx/1000 is the control track (ignored)

The RTP payload seems to contain a 4 byte extra header and then a 
complete and normal asf packet. (vlc discards the extra header)

So with this information fen (Laurent), did some hacking, and VLC is 
now able to play those streams. In theory with our new DirectShow 
decoder module, it will even work for WMV9 (on Windows only of course 
and not tested).

Just so that everyone knows, one more thing to look forward to in the 
next version of VLC :)
(two things if you count the WMV3 support on windows)

DJ

Thanks to Dennis 'Trax' van Amerongen (http://www.nob.nl) for providing 
on demand custom testing streams.
---
Universiteit Twente
Derk-Jan Hartman (d.hartman at student.utwente dot nl)
http://home.student.utwente.nl/d.hartman