The VideoLAN Forums

Hi forum,

we've been trying to get VLC to multicast out a stream we recieve over HTTP using the following command:

vlc -I "dummy" "$SURL" --sout "#rtp{access=udp,mux=ts,dst=${IP},port=${PORT},sap,group=Video${REV},name=tester${REV}}" :sout-all&

We find that this is working sometimes for a single stream, but the stream can randomly stop and restart (so I'm talking multicast packets out and also from a VLC client connected to the multicast video). Additionally, if we try and stream multiple videos from the same server then none of them work, the VLC command executes, we see some multicast network traffic out, but we can't connect to any videos from a VLC client.

We have some hardware multicast devices streaming video on the same network config that work ok, so we don't think the network is at fault.

Does anyone have any ideas what may be causing the issue, what we can do to improve things or troubleshoot further?

We are using VLC 3.0.4 on Ubuntu 18.04 LTS.

thanks in advance! Andy.

just been looking around for anything that might help, I came across mulitcat. I can pipe my stream into multicat and save it to file, like:

vlc -I "dummy" "http://my.network.stream" --sout="#std{access=file,mux=ts,dst=-}" | |multicat /dev/stdin /tmp/test3.mp4

but when I try and multicast out I get no error, but no traffic outbound on the mulicat NIC (just to confirm I do get traffic multicasting from vlc so network is working):

vlc -I "dummy" "http://my.network.stream" --sout="#std{access=file,mux=ts,dst=-}" | |multicat /dev/stdin @239.192.1.185:5000


Anyone have any ideas why mulitcat isn't working for me here? thanks again, Andy.

ok, strangely by dropping the "@" in the output for multicat I can connect to the stream :S
Still having choppy and total drop outs in the video unfortunately

Hi, from the manual:

For conveniency all tools use the same way of describing a socket in a
program argument:

<connect address>:<connect port>@<bind address>:<bind port>/<options>

All parts are optional; default port (1234) or wildcard address will then
be used.

Some examples:

Reading all streams coming to port 5004:
@:5004
Reading from a multicast stream on port 5004:
@239.255.0.1:5004
The same, with source-specific multicast:
192.168.0.1@239.255.0.1:5004
Writing to a multicast stream on port 5004:
239.255.0.1:5004
The same, but binding to a specific interface:
239.255.0.1:5004@192.168.0.2

So @239.192.1.185:5000 was reading, not writing.

For your issue, I don't have a clue for now :/

thnx for reply and clarification, had it my head the "@" was for setting multicast, obviously I was wrong!