Subject: Re: [ecasound] ecasound ladspa question
From: Kai Vehmanen (kai.vehmanen_AT_wakkanet.fi)
Date: Wed Jul 21 2004 - 14:25:26 EEST
On Tue, 20 Jul 2004, Aaron Heller wrote:
> If I have the following setup:
> ecasound \
> -a:1 -f:s24_be,1,96000 -i:W.raw -eac 400 \
> -a:2 -f:s24_be,1,96000 -i:X.raw -erc:1,2 -eac 0,1 -eac 400 \
> -a:3 -f:s24_be,1,96000 -i:Y.raw -erc:1,3 -eac 0,1 -eac 400 \
> -a:4 -f:s24_be,1,96000 -i:Z.raw -erc:1,4 -eac 0,1 -eac 400 \
> -a:1,2,3,4 \
> -f:32,4,96000 \
> -el:singlePara,8,12000,2.5 \
> -o:WXYZ.wav
[...]
> Where "singlePara" is a one-channel LADSPA plugin. Does ecasound make
> one instance and apply it only the first channel or are four instances
> made and applied to each channel. The latter is the behavior of Jack-Rack.
That's also true for Ecasound, if the plugin has exacly one input and
output, a new plugin instance is created for each channel when
processing multichannel Ecasound chains.
The problem with above setup is that you are adding singlePara four times,
once for chain '1', once for '2', and so on. As '4' is a 4ch chain, '3'
a 3ch chain, etc, there's quite a lot of processing overhead. But I guess
that shouldn't be a problem here, in any case singlePara is applied to
all input signals. One way a round this is to use:
ecasound \
-a:1 -f:s24_be,1,96000 -i:W.raw -ea:400 \
-a:2 -f:s24_be,1,96000 -i:X.raw -erc:1,2 -eac 0,1 -ea:400 \
-a:3 -f:s24_be,1,96000 -i:Y.raw -erc:1,3 -eac 0,1 -ea:400 \
-a:4 -f:s24_be,1,96000 -i:Z.raw -erc:1,4 -eac 0,1 -ea:400 \
-a:1,2,3,4 \
-o loop,1 \
-a:5 -i loop,1 \
-f:32,4,96000 \
-el:singlePara,8,12000,2.5 \
-o:WXYZ.wav
... also note the '-eac 400' to '-ea:400' change. You'll want to apply the
amplify to all channels.
> What happens when the LADSPA plugin is 4x4 (four inputs and four
> outputs, e.g., bf2quad).
Then Ecasound channels are mapped one-to-one to plugin inputs and outputs.
In other words you need to have a 4ch Ecasound chain to use bf2quad.
-- http://www.eca.cx Audio software for Linux!
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