Re: [ecasound] recording from jack

From: Kai Vehmanen <kvehmanen@email-addr-hidden>
Date: Thu Apr 13 2006 - 01:26:19 EEST

On Wed, 12 Apr 2006, Jure Pear wrote:

> I have a machine with two Maudio Delta 1010LT. The idea is to use its
> 16 analog inputs to record, compress and later stream on the net 16
> stereo channels (radio stations).
> I have CentOS 4 installed on a dual xeon server class machine. I began
> with .asoundrc from
>, figured out
> how to run jackd on it, hunted down many snippets of ecasound

It might be easier to just run a a separate ecasound instace for each
stereo pair:

ecasound -f:32,2,48000 -a:ch12 -i jack -o ch12.mp3

And then use some connection tools (like jack_connect, qjackctl, or
various others), to connect the two ecasound ports to the right soundcard
inputs. To help in scriptin, you can label the client with:

ecasound -f:32,2,48000 -a:ch12 -i jack -o ch12.mp3 -G:jack,ecarec_ch12

Ecasound client name will be 'ecarec_ch12' in the JACK graph (as shown by
jack_lsp or qjackctl).

> ecasound -f:32,16,48000 -a:1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 \
> -i jack_auto,alsa_pcm \
> -a:1 -f:s32_le,2,48000 -o ch1.wav \
> -a:2 -f:s32_le,2,48000 -o ch2.wav \
> -a:3 -f:s32_le,2,48000 -o ch3.wav \
> -a:4 -f:s32_le,2,48000 -o ch4.wav \

The main problem with this is the data is copied channel-wise in
ecasound, so although chXX:wav files will be in stereo format,
only the left channel will have audio. Mixing channels is a bit
more complicated, see...

The "Multichannel Processing" example at:

> ecasound ('h' for help)> engine-launch
> (eca-control) WARNING: No chainsetup connected. Trying to connect
> currently ... selected chainsetup.

You need to also start the engine with "start". You can
omit "engine-launch" in this case (only needed if you specifically want to
avoid actually starting the processing -- for example you want to control
start/stop from another JACK client).

> 2. Can I afford to run 16 lame processes to compress this to mp3?

Depends on the hw I guess, shouldn't be an impossible task although will
consume quite a bit of CPU.

> 3. What is the proper way in this setup to selectively turn on/off some
> channel? I'm planning to run ecasound in daemon mode and have a mngmt
> app connecting to it and controlling it.

Hmm, I'd still consider the one-ecasound-instance-per-stereo-pair
approach. Otherwise it is difficult to independently control the channels.

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Received on Thu Apr 13 04:15:08 2006

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