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Date:      Fri, 16 Sep 2011 10:52:54 +0700
From:      Victor Sudakov <vas@mpeks.tomsk.su>
To:        freebsd-questions@freebsd.org
Subject:   Re: Need an audio multicasting solution
Message-ID:  <20110916035254.GC92792@admin.sibptus.tomsk.ru>
In-Reply-To: <CAHieY7RQOFecrcCfSDtGjw-z1GU8RD8-%2BpkBpDkEaiu-usfppA@mail.gmail.com>
References:  <20110909062121.GA28440@admin.sibptus.tomsk.ru> <CAHieY7Tj-PyF52tRa8DMCdicqiOixLjSwT-QO67qT0PAirQyoQ@mail.gmail.com> <20110912055755.GA79151@admin.sibptus.tomsk.ru> <CAHieY7RQOFecrcCfSDtGjw-z1GU8RD8-%2BpkBpDkEaiu-usfppA@mail.gmail.com>

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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://239.8.8.8:5000 -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
useful.

> 
> 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@sibptus.tomsk.ru



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