[linux-audio-dev] Ecasound question

[Fons Adriaensen]

Thanks a lot Kai and Eric (see below) for your help.

On Tue, Feb 03, 2004 Kai Vehmanen wrote:

> ecasound -a:1,6 -f:32,12,44100 -i alsa \
>          -a:1 -f:32,1,44100 -o t1.wav \
>          -a:6 -erc:6,1 -f:32,1,44100 -o t6.wav \
>          -a:2 -i t2.wav -ea:200 \
>          -a:5 -i t5.wav -erc:1,5 -ea:200 \
>          -a:2,5 -f:32,10,44100 -o alsa
> 
> Input object with the most channels determines the channel count of the
> chain it is attached to. On the other end of the chains, if an output has
> less channels than the chain it is attached to, extra channels are
> discarded when writing to the output. With these simple rules you can 
> route audio between channels and chains, and without bloating the syntax 
> too much.

Shouldn't there be a  '-erc:1,2' on the t2.wav chain (it should go to
ouput 2) ?

> The '-ea:200' at the end of chains 2 and 5 helps to keep the volume
> constant. This is ugly, but unfortunately something I cannot fix at this
> point (I'd like to change the chain-mixing semantics from add'n'divide to
> plain add'n'saturate like in most other systems, but unfortunately doing
> the change now would break far too many existing scripts/sessions :( ...).

Why is this necessary ? Nothing should be mixed... unless alsa inputs
2 and 5 are also mixed in. If this is so, can it be prevented ?


and Eric Dantan Rzewnick wrote:

> -a:t2 -i t2.wav -erc:1,2 -f:32,10,44100 -o alsa,hw:0
> -a:t5 -i t5.wav -erc:1,5 -f:32,10,44100 -o alsa,hw:0
> 
> -a:t1 -f:32,14,44100 -i alsa,hw:0 -f:32,1,44100 -o t1.wav
> -a:t6 -f:32,14,44100 -i alsa,hw:0 -erc:6,1 -f:32,1,44100 -o t6.wav

I kind of like this 'per chain' way of writing things. Would adding
'-erc:1,1' to the a:t1 chain hurt in any way ? It would be nice to
have a uniform syntax.

-- 
Fons