Subject: Re: [ecasound] Question about multichannel sound cards
From: Jeremy Hall (jhall_AT_maoz.com)
Date: Mon May 19 2003 - 23:01:07 EEST
but in your erc effects you will want to reverse the arguments, currently
with this example you'll get 4 copies of channel 1.
_J
In the new year, Kai Vehmanen wrote:
> On Thu, 15 May 2003, Aaron Heller wrote:
>
> > I'm a novice user and still trying to understand all this. Could you
> > explain why using jack is better than the following for recording to
> > multiple files.
> [...]
> > ecasound -f:32,4,96000,i -a:1,2,3,4 -i:alsaplugin \
> > -a:1 -f:32,1,96000 -erc:1,1 -o:track-1.wav \
> > -a:2 -f:32,1,96000 -erc:1,2 -o:track-2.wav \
> > -a:3 -f:32,1,96000 -erc:1,3 -o:track-3.wav \
> > -a:4 -f:32,1,96000 -erc:1,4 -o:track-4.wav
>
> Actually there's nothing wrong with the above. Problems come up when you
> want to use really high channel counts, let's say 12 or 24 input channels.
> With 4 channels and the above routing approach, ecasound will use 4x4ch
> worth of memory bandwidth for demultiplexing. This is not a big problem,
> but 12x12ch starts to be...
>
> So using JACK is not absolutely necessary, but it does provide a nice
> solution to optimizing multichannel use scenarios. But, but, what's
> importannt in the end is what works for you. If your machine can handle 24
> channels with the routing approach above, then use that. If you run out of
> cpu power, then you can try JACK.
>
> > And.... I've been using the following to playback M-S recordings to
> > L-R (L = M+S, R= M-S). Is there a better way.
> [...]
> > ecasound -c -r -b:2048 -z:db \
> > -a:1 -i:m.wav -ea +100 -erc:1,2 \
> > -a:2 -i:s.wav -ea:+100 -erc:1,2 -epp:0 \
> > -a:3 -i:s.wav -ea:-100 -erc:1,2 -epp:100 \
> > -a:1,2,3 -f:16,2 -o:alsaplugin
>
> I guess this is currently the best way.
>
> > Ideally, I'd like to tie the setting of -ea together, under a single
> > real-time control to compute: L = kM + (1-k)S, R= kM - (1-k)S, where
> > 0.0<k<1.0.
>
> I'd say writing a new chain operator (or a LADSPA plugin) for this is the
> best solution (takes 'k' as its parameter).
>
> --
> http://www.eca.cx
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>
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