Subject: Re: [ecasound] Re: "Device busy" w/ multitrack capture on Delta-66
From: Kai Vehmanen (kai.vehmanen_AT_wakkanet.fi)
Date: Wed Sep 04 2002 - 00:15:50 EEST
On Tue, 3 Sep 2002, Anthony wrote:
> ecasound -f:s32_le,12,48000,i -a:1,2,3,4 -i:alsa,ice1712 \
> -a:1 -f:s32_le,2,48000,i -erc:1,1 -o:stereo1.wav \
> -a:2 -f:s32_le,2,48000,i -erc:2,2 -o:stereo1.wav \
> -a:3 -f:s32_le,2,48000,i -erc:3,1 -o:stereo2.wav \
> -a:4 -f:s32_le,2,48000,i -erc:4,2 -o:stereo2.wav
> I just tried it and it seems to work. Maybe Kai or someone else can
> comment on better approaches. Is it possible to make aliases for
Actually this isn't quite correct. You are not allowed to have
multiple chains attached to the same file. Let's make a few mods:
ecasound -f:s32_le,12,48000,i -a:st1,st2 -i:alsa,ice1712 \
-a:st1 -f:s32_le,2,48000,i -o:stereo1.wav \
-a:st2 -f:s32_le,2,48000,i -erc:3,1 -erc:4,2 -o:stereo2.wav
I've been meaning to add new stereo channel-route operators that would
shorten these command lines at least a bit.
Another big improvement would be a demux audio object. This has been on my
todo-list for a long time, but I've always thought that this will be
handled in ALSA sooner or later, so I've never actually implemented the
functionality. But as it seems that implementing a generic driver level
channel demuxing is not entirely easy (btw; OSS/commercial provides this
although with other type of limitations), it might make sense to add this
Anyway, here's how I've thought the demux would work:
ecasound -f:s32,12,48000,i -i ice1712 \
-f:32,4,48000,i -o demux,foo1.wav,foo2.wav,foo3.wav,foo4.wav
Ie. after the keyword 'demux', you'd just list filenames for each mono
file. Here I limited the output count to four channels to avoid typing 12
filenames. ;) Also, there could be a separate stereo_demux which would
output stereo-pairs to separate files.
I don't see much use for the reverse case, ie. a 'mux' object
> format strings like an effect preset:
> f12 = -f:s32_le,12,48000,i
> and then
> ecasound -pn:f12 ....
Unfortunately this isn't currently supported. But I'll put this on my
might-be-implemented list. It's common that you only use one or two
different formats in normal use. It would make sense if you could define
presets for these formats. So something like: -F:cd, -F:dat,
-F:ice1712 (native hw-format) and so on.
-- http://www.eca.cx Audio software for Linux!
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