The VideoLAN Forums

Hello,

I am trying to use VLC to convert about 25 UDP unicast streams to multicast and I'm having problems with the load on the CPU. After 5 or 6 streams, the CPU use gets up over 90% and the system is unstable. The test server is 2x 3.4GHz & 2GB RAM. It's currently on Windows but I'm not sure CPU use would be much better with Linux.

Transcoding obviously uses a lot of processing power but I'm not converting the feeds at all. The source for each feed is a satellite receiver with UDP unicast output over Ethernet. The original MPEG-2 ~3-5 Mbps streams are not changed at all and I'm simply trying to convert them from unicast to multicast for use on an in-house LAN.

I'm a little confused as to why it would take so much processing power since the feeds are not being decoded or transcoded.

I'm launching VLC with the telnet interface and loading a VLM config file:
Again, the feeds do convert to multicast and I can play them out using the specified multicast address with VLC as a client. I'm only concerned about the CPU load and the inability to do more than 5 or 6 streams.

I have also tested using a MPTS multicast stream as a source and trying to split it into 5 separate multicast streams (one for each program in the multiplexed source multicast, using "udp://@239.1.1.199:4410 :program=1" [... program=2, etc] as the source) and find comparable CPU load issues. (The reason for splitting the multicast is to reduce network load for the clients... so they're only using bandwidth for the channel they're watching rather than for a group of channels concurrently).

Any help would be greatly appreciated.
Thanks.

Hi kmarchand,

Have you really been able to split an MPTS in multiple SPTSs using vlc? I am trying to do this and I have tried all the versions of starting from 0.8.6i till the latest but unable to do. In your post you mention that -

"I have also tested using a MPTS multicast stream as a source and trying to split it into 5 separate multicast streams (one for each program in the multiplexed source multicast, using "udp://@239.1.1.199:4410 :program=1" [... program=2, etc] as the source) and find comparable CPU load issues. (The reason for splitting the multicast is to reduce network load for the clients... so they're only using bandwidth for the channel they're watching rather than for a group of channels concurrently)."

I tried the same command but it only opens the vlc GUI there is no video. If you try "vlc --sout udp://@239.1.1.199:4410 :program=272" (272 is program id) it tries to stream but fils. The error messages are as follows :

main error: cannot resolve @239.1.1.199 port 4410 : Host or service not found
access_output_udp error: failed to open a connection (udp)
main warning: no sout access module matching "udp" could be loaded
main error: cannot delete object (306, (null)) with children
stream_out_standard error: no suitable sout access module for `udp/ts://@239.1.1.199:4410'
main warning: no sout stream module matching "std" could be loaded
main debug: destroying chain... (name=std)
main debug: destroying chain done
main error: stream chain failed for `std{mux="",access="udp",dst="@239.1.1.199:4410"}'
main error: cannot start stream output instance, aborting
main debug: thread times: real 0m2.359375s, kernel 0m0.000000s, user 0m0.000000s
main debug: thread 3984 joined (input/input.c:412)
main: nothing to play

I am using vlc 0.8.6i Janus version. Please let me know which version you are using to split the Multicat MPTS into multiple Unicast or Multicast SPTS.

Thanks in advance.