VLC and Multicast Streams

[wmgries]

Is it possible to use VLC to receive multicast streams? I have a project that I am interested in using this player with but unless I won't be able to if I can't figure out how to use it for this purpose (if it's even possible). VLC would be a great choice for this project because it works on Windows, Linux and Mac so I've got my fingers crossed it can receive multicast streams.

Thank you

[Rémi Denis-Courmont]

Yes, of course.

[wmgries]

I forgot to mention that it's an http multicast stream.

[Rémi Denis-Courmont]

There is no such thing as HTTP multicast.

[wmgries]

I access it from an address on my local intranet. Streams are formatted as http://myintranet/example.nsc.

I'm using Windows Media Services to broadcast this from a Windows 2003 server.

My eventual goal of using VLC is to embed it into a website available from within my intranet for easy access. Using VLC is preferable because I don't have to track down different players for Windows, Linux and Mac.

[msupstream]

I believe HTTP uses TCP, and is made for unicast. TCP is not suitable for multicast streaming, hence you should perhaps find a protocol that can use UDP instead. I have used VLC to play streams using RTSP and RTP. RTP is well suited for multicast as it can use UDP as the underlying protocol. Or are you using HTTP mainly for the setup of the multicast stream, and actually multicasting with i.e. UDP?

[yohann.martineau]

multicast http is not employed in your case (actually, I think multicast http does not exist), windows media player downloads a descriptor file (.nsc) via http. This files contains encrypted multicast ip address and media port. And then it sends IGMP messages to join the multicast group where the media stream is being streamed over udp. If you know the multicast address and the media port you can open the media streams with vlc.

Actually, it's a bit more complicated... because windows media player and windows media server will try to "negociate" the best way to stream the video: it will try several things: multicast udp, unicast udp, raw tcp, http over tcp, etc. It will try to choose the most "network-friendly" way to stream the video.

[wmgries]

multicast http is not employed in your case (actually, I think multicast http does not exist), windows media player downloads a descriptor file (.nsc) via http. This files contains encrypted multicast ip address and media port. And then it sends IGMP messages to join the multicast group where the media stream is being streamed over udp. If you know the multicast address and the media port you can open the media streams with vlc.

Actually, it's a bit more complicated... because windows media player and windows media server will try to "negociate" the best way to stream the video: it will try several things: multicast udp, unicast udp, raw tcp, http over tcp, etc. It will try to choose the most "network-friendly" way to stream the video.

That doesn't sound good for my hopes of using VLC to be able watch these streams. Is there some sort of back way to work around this issue?

[yohann.martineau]

Is your network multicast-enabled?
You can try to install wireshark on your computer, and make a network capture of what's happening between windows media player and windows media server.

If you see igmp packets and then a huge amount of udp packets, you can try to open the multicast address of the igmp message. For the port number, take the destination port of udp packets.

If you see udp packets, but not with 2xx.x.x.x destination address, your network is not multicast enabled.

[wmgries]

Is your network multicast-enabled?
You can try to install wireshark on your computer, and make a network capture of what's happening between windows media player and windows media server.

If you see igmp packets and then a huge amount of udp packets, you can try to open the multicast address of the igmp message. For the port number, take the destination port of udp packets.

If you see udp packets, but not with 2xx.x.x.x destination address, your network is not multicast enabled.

This wouldn't work, I think my network is blocking it. I am sure however that the stream is a multicast one. Why can't VLC resolve the file?

[wmgries]

I went into the Windows Media Services application directly and tracked down one of the streams that I am hoping to view with VLC. I have the IP address and port number but when I type them into the multicast udp spot on VLC, it doesn't seem to want to work.

It is possible that a different Media server (on Server 2003) could be used... but I don't know if any that are up to the job. I need a media server that is capable of multicast and being able to push out like 30 different streams at once.

Thanks for all the help!

[wmgries]

Anybody?

[wmgries]

Still nothing?

[yohann.martineau]

use vlc as a streaming server and vlc as the client. With an intel centrino duo with 2GB of memory (dell precision m4300), you can stream up to 35 streams.

http://www.videolan.org/doc/streaming-h ... l#id312308

[markh]

I believe that this is the syntax for viewing a udp stream, please correct me if I'm wrong.

udp://@<multicast-group-address>:<udp-port>

I'm using this to view an Ikusi IPTV transcoder with the following url for example.

udp://@225.0.0.4:1234

and it works a treat. I think however that WMS uses its own proprietary protocol over udp to control the "users' streaming experience", but I'd be interested to know how you go viewing a WMS generated multicast stream with vlc.
Are there ways to 'decrypt' the .nsc announcement file used by the WMP to view the stream? The wireshark idea sounds like a good one. If you're having trouble using wireshark just plug into the WMS server with a x-over cable then run WMP to start the server streaming.

I hope that this helps.

mark