Subject: Re: [ecasound] mixing with -ei in eiam?
From: Kai Vehmanen (k@eca.cx)
Date: Tue May 08 2001 - 05:59:25 EEST
On 1 May 2001, Mario Lang wrote:
>> importantly, it is practically useless in multichain setups. :( You should
>> try the LADSPA pitchshifter plugins instead.
> Ahm, I installed LADSPA yesterday (and I am amazed!) but I didnt
> find a plugin like this. Could you point me to a website and/or plugin name
> which does this. The only thing I found was the pitchShifter, but
> that one only shifts pitch, and doesnt change the speed of the track.
> I want to change both. I want ecasound to behave like a digital turn table...
Aa, true, pitchShifter doesn't change the duration of processed audio
blocks. Hmm, this might turn out to be more difficult than I thought. For
efficiency, ecasound engine requires that all chains operate one block (x
sample frames) at a time. Ie. all inputs produce x samples, which is then
easy to mix to chains, and afterwards to outputs. The -ei:x pitchshifter
breaks this design, as individual -ei can take x samples, but produce
1.5*x samples. With only one chain, this works ok, but otherwise it gets
messy. Picture that we get x samples from one chain, 1.1*x from other and
1.5*x from the third. It's impossible to just mix these together and write
to output...
If you need to you play multiple files, but at a different speed, it
probably requires a special input device (ie. not effect or a plugin).
Hmm, you could simulate this by using raw audio files:
ecasound \
-a:1 -f:16,1,22050 -i input1.raw \
-a:2 -f:16,1,23000 -i input2.raw \
-a:1,2 -f:16,2,44100 -o /dev/dsp
... and here input1.raw and input2.wav really are sampled at 44110Hz. By
using -f:x,x,freq you can select the speed with which the input files are
read.
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