Need an audio multicasting solution

Victor Sudakov vas at
Fri Sep 16 03:52:58 UTC 2011

Alejandro Imass wrote:
> >
> > A quick look at Icecast showed that it does not support multicast either.
> > It this true? If so, Icecast is completely useless for my scenario.
> >
> AFAIK very few media streamers (or none) actually support real IPv4
> (Class D) Multicast. They support what is known as "application
> multicast" akin to a multi-process/multi-threaded Web server.
> I don't know much about real IPv4 Multicast but I've heard it's not
> that easy to do in the real world and would probably require
> coordination with your ISP unless you're multicasting in a private
> networks.

I use multicasting in a corporate network.

> Again, IMHO because I've never even attempted multicasting.

It's fun and very pleasing aesthetically :) At least on Cisco.

As to the original question. I have had some success with
multimedia/ffmpeg, at least this:

ffmpeg -i file.mp3 -acodec copy -f rtp rtp:// -re

does send a multicast stream which can be listened to with VLC (but
not mplayer for some reason) on multiple hosts.

Now I need to figure out how to stream live sound from /dev/dsp. All my
attemps to record sound from a USB audio interface have resulted so
far in a severely distorted growl instead of normal voice. Does
anybody know how to figure out the sampling rate and other parameters
of the sound card? "cat /dev/sndstat"  does not output anything really

> Why do you need multicasting anyway?

To save bandwidth mostly, and it's fun to setup :). Taking into
account that I have PIM working across all our WAN links (an in-house
monitoring/alarm system relies thereupon), it would be nice to use
this infrastructure for sound too.

Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at

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