RTSP Multicasting with Windows Media Player

[workhn]

Is there a way to implement RTSP Multicasting that Windows Media Player can understand?
Now I use command:

Code: Select all

vlc /tmp/deti.mpg vlc:quit --sout '#rtp{dst=239.255.100.100,sdp="rtsp://192.168.0.55:8080/test"}'

It works with all players except Windows Media Player. What should I do to get it working?

[Jean-Baptiste Kempf]

Use mms for WMP.

[workhn]

I have to use rtsp, because mms don't support multicast. And I have to use multicast because it's requirement of my chief.
If there is another way to stream multicast w/ WMP, it fits too.

[VideoCheif]

Windows Media multicasting is done using a Windows Media Server.
The Windows Media server must be running Windows Server 2003 and have Windows Media Services 9 (a free optional component) installed on it. Although all versions of Windows Server 2003 have Windows Media Services 9 available for installation, only the Enterprise and Datacenter editions allow the use of multicast. Earlier versions of Windows Server, such as Server 2000 and NT 4.0, used Windows Media Services 4.1 which did not offer multicast.

A Windows Media server receives a stream from a Windows Media encoder. The server then generates the multicast. It is not possible to create a multicast directly from a Windows Media Encoder. I belive the protocol that is used for the multicast is UDP, not RTSP or MMS. By the way... Strictly speaking, MMS has been depreciated. Most MMS streams now roll over to RTSP invisibly to the end user. Windows Media Services 9 on Server 2003 does not offer or support MMS.

In order for Windows Media Player to decode and play a Windows Media multicast, it must receive specific metadata about the multicast stream. Other streaming technologies distribute this metadata via SDP or SAP. Windows Media uses neither of these but instead uses a proprietary approach which is centered around a small stream descriptor file called an .NSC file. This file must be made avaiable to the Windows Media Player. The easiest way to achieve this is through a web server. Although it is technically possible to put the .NSC file on each and every client/player computer, it is not generally feasible to do so. The assumption is that if you are multicasting, it is inteneded for a very wide audience and copying the file to hundreds or thousands of client computers would not be practical. By publishing or distributing a link (such as via email or on a well known web site) to the file on a web server, it is possible for a wide audience to access the multicast. The file is only a few KB and does not require much network bandwidth. Although it is not required it is possible to enable IIS on the Windows Media Server and serve the file from the same server. The additional load on the media server is generally insignificant.

When a multicast publishing point is created on a Windows Media Server, the multicast wizard will walk the user through the process of creating an .NSC file as well as an optional .ASX file. The .ASX file is a convient indirect way to disclose the location of the .NSC file. Amongst other advantages, it has the ability to list several possible locations for the file and if the first location listed does not respond, Windows Media player will step to the next location listed in the file and try to find it there. When setting up the multicast and creating the .NSC and .ASX files, it is useful to have a basic understanding of how to configure IIS on the Windows server and HTTP in general.

A typical .NSC link would look like: http://server.name.domain/file_location/file_name.nsc
The server name can be an FQDN, simple DNS name, WINS name, or IP address. All of them are valid and would all work. In an enterprise application, it generally advisable to use the FQDN or other DNS name. Also, the file can reside in the root/default IIS directory so file_location is not technically required.

The NSC file will provide the keys to the castle for the Windows Media Player; what the multicast group address is, what port it is on, what the bit rate is, what video codec is in use, which audio codec, copyright info, etc.

We are multicasting a ~600 kb/s Windows Media stream at my organization through this process and it is very sucessful. I have also sucessfully tested multicast Windows Media streams at rates up to 768 kb/s via satellite and put the .NSC files on a (terresterial) web server.

Unfortunately, I have not yet been able to get VLC (0.8.6) to play a Windows Media multicast.

I hope this helps. I apologize if I've missed the point of the question and bored you.

[workhn]

Thanks.

[dionoea]

You cannot use VLC to listen to Windows Media Server multicast streams. You cannot use VLC to stream multicast to Windows Media Player (well ... you can using plain UDP/TS multicast if you have the Moonlight plugin installed in Windows Media Player). We'd be glad to help anyone wishing to implement those features in VLC though (We already have a module to decode the Microsoft multicast description file ... we just can't use it yet. thedj (The DJ in this forum) gave it a try once but he never finished. There's a (long) forum thread about that somewhere.)