Re: [ecasound] Making a mix from multiple WAVs faster

From: Kai Vehmanen <kvehmanen@email-addr-hidden>
Date: Tue Aug 05 2008 - 19:29:51 EEST


On Mon, 4 Aug 2008, Stuart Allie wrote:

[example of loop device use in user's guide]
> Sorry I didn't see this before - might have save you some time. The
> documentation is wrong. When you assign chains to an output, it

wow, that's pretty bad. The example in the user's guide is now
fixed (online plus in the git tree).

> disconnects any chains already assigned to that output and then connects
> only the currently selected chains. I don't think the documentation
> spells that out explicitly anywhere.

Actually this is a special case that only applies to loop devices.
Normally, whenever you have a "-i:foo" or "-o:foo" option, a new object is
created. If you specify "-o:foo" twice, two separate objects are created.
The only exception to this is the loop device. The loop id number is a
global value, and for a given ID (e.g. '1', all loop input/outputs (e.g.
'-i:loop,1' and '-o:loop,1') will point to the same to same object

I guess ecasound should detect this specific case and give a proper
error message. In theory ecasound could also "fix up" the chainsetup
so that:

  ecasound -a:1 -i foo -o loop,1 \
           -a:2 -i foo2 -o loop,1

... would be automatically converted to the correct syntax:

  ecasound -a:1 -i foo -a:2 -i foo2 \
           -a:1,2 loop,1

But this is a bit dangerous, as with other input/output types the above
two commands really are different. E.g.:

  ecasound -a:1 -i foo -o jack \
           -a:2 -i foo2 -o jack
  ecasound -a:1 -i foo -a:2 -i foo2 \
           -a:1,2 jack

Both commands will work, but cause different things to happen: the first
one will create two JACK client objects ("foo" and "foo2" not mixed),
while the latter will create just one (the files are mixed).

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Received on Tue Aug 5 20:15:17 2008

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