Icecast - Aug 2004 - Q: Is it possible?

Hola Mac (qué bien, un español ;-)  )
> I would reserve a mountpoint for each one of these sources:
>-Spain = my_radio.mp3 (Your listeners will listen to this mountpoint ONLY)
>-Honduras = Honduras.mp3
>-Guatemala = Guatemala.mp3
Ok, it's seemed to my conversation with Eric. My Bc server will receive N
sources, mix them and broadcast the final results, but I see some differences
(or doubts cause my inexperience on audio streaming, I'm sure)

I thought that an streaming scenario was basically:

* A broadcast server (icecast server)
* A source (liveice, iceS ... )
* some receivers (WinAmp)

Translated to this project:

* Bc server with icecast server (independent of the final signal treatment  -
analog, digital - ... )
* N speakers around the world, each one with your microphone and your liveice
station, ready to speak live.
* many many people with WinAmp and ready to enjoy this radio ;-)

I confused with "you use Winamp/Oddcast as source clients". Do you
refer WinAmp can work as liveice? or related to your latest comments, too, 
"You can run more than one instance of Winamp/Oddcast and use a silent
output plugin". Do you refer each speaker (honduras, caracas, barcelona)
must to have a bc server too, and into the central studio I must to have various
Winamp to listen each remote server for to mix and to resend the result to the
central broadcast server?

returning to my first mail the more "strange" scenario could be a
program with N remote collaborations. More than one speaker live on the same
program, one in honduras, one in madrid, one in caracas ...  bcause the people
that will work in this project (the speakers at the central studio) come from a
"traditional" radio world and they like to have an analog mixer to
control the faders and the collaborations live , my idea was to set up an
"easy" way to afford their daily work. The more easy way for them
could be to have an analog mixer with N inputs, one for the principal speaker,
one for each remote speaker, the stereo channels for music files,  the master
output (to the bc server)...

In this way, I can assume that in an input channel (analog mixer) I can attach
pre-mixed sources with your method (although still I haven't understood it
well :-(   ) so I could to pre-mix the remote speakers to one stereo input
channel to the analog mixer. it's ok?, so this means that now I will need:

* 1 card for all the remote speakers (to pre-mix and reserve only 1 stereo input
line)
* the rest will be mixed live directly on the analog mixer (music files,
principal speaker ... )
* All the remote speakers will have a microphone and a pc station (previous
doubts Winamp vs liveice)
* Even so if i need I can "associate" one source with one card (only
forecast) and send the signal to one input channel.

OK?

I like it .. this world is very very interesting

very very thanks, Mac and Enrico

<p>----- Original Message ----- 
From: "MacSym" <macsym69@yahoo.fr>
To: <icecast@xiph.org>
Sent: Wednesday, February 11, 2004 11:58 PM
Subject: RE: [icecast] Q: Is it possible?

<p>Hi Raul,

Here is how I would set it up to answer your scenarios:

-One Icecast server in Spain.
-One source in Spain
-One source in Honduras
-One source in Guatemala (for example)
...

I would reserve a mountpoint for each one of these sources:
-Spain = my_radio.mp3 (Your listeners will listen to this mountpoint ONLY)
-Honduras = Honduras.mp3
-Guatemala = Guatemala.mp3
...

Let's say you use Winamp/Oddcast as source clients. If, you want to
broadcast a live from Honduras, you won't ask your listeners to switch to
"Honduras.mp3" so you have to set up your Spanish source
(Winamp/Oddcast) to
listen to "Honduras.mp3" and resend the stream to
"my_radio.mp3". In this
way, there will be a smooth transition between the Spanish and the Honduran
sources because the final user will always listen to "my_radio.mp3"
(not
Honduras.mp3 or Guatemala.mp3).

Also, if you want to listen to several sources without broadcasting it on a
single computer, you don't necessarily need several soundcards. You can run
more than one instance of Winamp/Oddcast and use a silent output plugin
(attached to this mail). In this way, the audio pipeline is managed by
software and not hardware.

I don't know if it's the best solution, but I am just suggesting.

Saludos de Barcelona,
(¡Yo tambien escribo desde España!)

MAX

 

-----Original Message-----
From: owner-icecast@xiph.org [mailto:owner-icecast@xiph.org] On Behalf Of
Raúl Wild-Spain
Sent: Wednesday, February 11, 2004 11:03 PM
To: icecast@xiph.org
Subject: Re: [icecast] Q: Is it possible?

wow, Enrico ... it's a great help ;-)

I comment:

----- Original Message -----
From: "Enrico Minack" <enrico.minack@informatik.tu-chemnitz.de>
To: <icecast@xiph.org>
Sent: Wednesday, February 11, 2004 8:00 PM
Subject: Re: [icecast] Q: Is it possible?

<p>> Hi Raúl,
>
> interesting project ;-) So this is what I would recommend. For a number of
> remote speakers (1 or more) it would make sence to mix them together in
the
> studio the local speaker is located.
>All remote speakers could mount as a
> source at the broadcast server (shouldn't be a problem to have a bigger
> distance between them).
Ok, the first is more or less what I thought (and what i need), mix them
together in the "local" studio (where will exist the broadcast
server,too)

mmm ... but I confused with  "... mount as a source at the broadcast
server...". Do you refer each remote location will have an streamer client
(pc) to send their signal (through Inet) to the broadcast server? or another
way?

<p>>Other way would be to have a icecast server at
each
> remote speaker's location.
They want only a central broadcast server for controlling and planning the
kind of  programs (and to mount them).
> However, a PC could play these streams from the broadcast server on a
number
> of soundcards and the output of them is put into an analog mixer where the
> local speaker can control the volume and can listen into the stream
without
> broadcasting. The main audio output from this mixer goes into the
broadcast
> server which creates the final stream.
OK.. I'm digesting ;-)) ...

... and analyzing ...
* I will have a broadcast server (bcs).
* this bcs will have various soundcards (n +1 -> N speakers + 1 final mix)
* the output of each soundcard is put into the analog mixer.
* the remote clients will send the signal to the bcs (through liveice?) .
* these channels will be received by bcs (and not broadcasted) and will
output them to the analog mixer (one channel per soundcard).
* The local speaker (or producer) will mix all and will send the results to
the bcs.
* the result will be broadcasted ...

right?

More doubts:

- about soundcards: are important terms like "latency 0"?or MP3
decoding by
hardware?, do you know  RME digi9336? can you recommend me any soundcard?

- Do you know if it is possible to control an MP3 file list  manually
( for example if someone want to launch these files one by one and on demand
while mix the rest of remote channels - it could be another pc playing as a
MP3 server ... )

- the rule 1 soundcard = 1 remote speaker isn't fixed, right?. If the number
of speakers grows I will have some way to mix various sources to the same
soundcard. yes?

one bcs routing various "channels" to each soundcard is possible with
one
icecast server or I will need N icecast servers on the same machine?
>
> This is how we make live broadcast from remote venues.
then it's all guaranteed !!!  ;-))
>
> I hope I could help some,
> Enrico M.
It has already been a great help,
;-))
>
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I'd like to relay content running on an icecast server to a Darwin 
Streaming server.

Darwin doesn't have relay capability. Icecast can pull from one 
server to make content available on another.

What are my options for grabbing a source at one server and sending 
it on another without re-encoding?

-- 
Bryan Walls                             My words are not NASA policy.
Bryan.Walls@nasa.gov        	       (256)544-3311voice,544-8752fax
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> What are my options for grabbing a source at one server and sending
> it on another without re-encoding?
find a client for icecast (mpg123, wget, fetch, ...), put the content to
standard out, find a source for darwin (sorry, I don't know any) and let it
use the standard in.

Enrico

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Hi:

If you have a card like an SB Live, you could have all the remote streams
playing and use something like alsamixer to set the volumes of these
sources relative to each other, and then feed the lot through one mixer
channel on your mixer.

You will hit two problems though.  The first is that you will need to have
a stream for remote participants to listen to.  Finding a way to send the
local host plus all other remote parties but not their own voice out to
them will be tricky.  If they can cope with hearing their own voice coming
back to them, or you can send them a mix where you can mute the remote feed
for them while they are talking, then perhaps you'll be OK.

The other problem you'll hit is latency.  Not sure how much of a problem
this will be, it all depends on how much buffering both the source and
client programs use.  If you're using MP3, you could use something like
mpg123 to play the remote streams, which uses very little buffering.  But
it's possible that the latency will be too big to be workable.  If you
could use speex with icecast or some other tool using speex for remotes,
then you'd be OK.

In fact, both these problems *could* be solved by using something like the
open H323 programs and using their conference server to connect everyone.
Pretty low latency and everyone would hear everyone else without hearing
themselves.  The only bummer about open H323 is that I don't know how to
get the sampling rate any higher than 11khz, which is not really good
enough for broadcasting (IMHO).

BTW: AFAIK, you can't use liveice with icecast2, you can use darkice
though.

Geoff.

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very thanks, Geoff, your comments are really important, 

----- Original Message ----- 
From: "Geoff Shang" <gshang@pacific.net.au>
To: <icecast@xiph.org>
Sent: Friday, February 13, 2004 3:39 AM
Subject: Re: [icecast] Q: Is it possible?

<p>> Hi:
> 
> If you have a card like an SB Live, you could have all the remote streams
> playing and use something like alsamixer to set the volumes of these
> sources relative to each other, and then feed the lot through one mixer
> channel on your mixer.
OK. The only doubt I have about this; I always understood that pre-mixing must
occurs into the broadcast server (or better on another pc listening these
mountpoints?). I say, I will have mountpoints for each remote speaker and there
will be a way to pre-mix and put them to the analog mixer. If I not mistake this
can be translated as to have 1 winamp per mountpoint playing their source.mp3
and mixing on alsamixer... it's right or there are another and better way?

another doubt is: 
How to send the final mix (from analog mixer) to the bc server? would be right
to have a source client on the same machine where is installed icecast server to
convert the final mix?
> 
> You will hit two problems though.  The first is that you will need to have
> a stream for remote participants to listen to.  Finding a way to send the
> local host plus all other remote parties but not their own voice out to
> them will be tricky.  If they can cope with hearing their own voice coming
> back to them, or you can send them a mix where you can mute the remote feed
> for them while they are talking, then perhaps you'll be OK.
> 
> The other problem you'll hit is latency.  Not sure how much of a
problem
> this will be, it all depends on how much buffering both the source and
> client programs use.  If you're using MP3, you could use something like
> mpg123 to play the remote streams, which uses very little buffering.  But
> it's possible that the latency will be too big to be workable.  If you
> could use speex with icecast or some other tool using speex for remotes,
> then you'd be OK.
> ....
Does someone know more about speex vs icecast?

I'm reading about speex and is very interesting. There are speex plugins for
WinAmp and seems to be capable to sampling till 32Khz. Perhaps there would be a
way to send (speex based) a final mix to all speakers ...

... how another Icecast-users achieve to solve this trouble today? returning
"a mix" to a remote speaker and avoiding latency problems ... is not a
common scenario? I'm the one? ;-)

best regards,

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> You will hit two problems though.  The first is that you will need to have
> a stream for remote participants to listen to.
Yeah, that's right. If you want the remote speakers to be able to listen to
the other speakers this becomes a little complicated. If you hear your own
voice with a latency more than 1/10 or 1/5 second it becomes very
distracting! This latency really is a problem.

And mixing a certain signal for every remote speaker also means a huge
effort. And you need to decode each of this signal, which means you need to
create N MP3 streams, that's a lot of CPU laod.

But the remote Users don't need to hear the local speaker in 128kBit
quality, therefore you could establish a H323 session with all remote
speakers and the local speaker in it (if H323 works with multiple clients,
I'm not sure). This can be in low quality. Everybody can hear the other
speakers and vice versa. For broadcasting, the high quality signal from each
remote speaker is send to the studio (just one direction).

Here are pictures of the two layers, layer 1 is the icecast MP3-stream,
layer 2 is the H323 RTP-stream:
http://www-user.tu-chemnitz.de/~mie/layer_1.gif
http://www-user.tu-chemnitz.de/~mie/layer_2.gif

But I doubt that 2 programs (ices and the H323 software) can capture the
microphone channel of one soundcard simultaniously. Maybe there are
technologies out there to grant multiple access (I am sure there is),
otherwise two soundcards and two mics at each remote speaker location would
be necessary :-(

Well, this is getting quite complex ;-) I love it, though!

Enrico

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