Subject: Re: [ecasound] Trouble with capture and latest alsa
From: Kai Vehmanen (k@eca.cx)
Date: Fri Jul 13 2001 - 00:24:06 EEST
On Wed, 11 Jul 2001, toby wrote:
> I am using ecasound 2.01 with Alsa 0.9beta5 and a
> Midiman Delta44 card. Everything works correctly
> but recording. I don't know how to use the dsp_name
> with alsa, (how does one, btw) so I used:
[...]
> ecasound -i:alsahw,0,0 -o:foo.wav
When using direct hw-access (= 'alsahw'), you need to be sure that the
recording format is actually support by hardware. Here you tried to open
the Delta44 for recording 16bit-stereo-44kHz (default audio params in
ecasound) data. Most cards dont' support many formats in hardware
(conversions are better handled in software).
I don't know enough about Delta44 to give you better instructions, but you
should try something like:
ecasound -f:16,4,44100 -i:alsahw,0,0 -f:16,2,44100 -o:foo.wav
ecasound -f:32,1,44100 -i:alsahw,0,0 -f:16,2,44100 -o:foo.wav
.. etc, see 'man ecasound' for more info on the -f option. ALSA also
has a plugin-access mode, where ALSA will transparently convert between
various audio formats. As I haven't had time to follow recent ALSA
developments, I'd recommend you to ask about this on ALSA's own
alsa-user list. But in any case, you should be able to record with
'alsahw,0,0'. It's just a question of convenience.
> ERROR: [ECA-CHAINSETUP] : "Enabling chainsetup: AUDIOIO-ALSA3: Audio
> format not supported."
Yup, you tried one set of audio parameters, and Delta44 replies that "I
don't support that, try something else.". :)
> ecasound -i:/dev/dsp -o:foo.wav
> That worked but yeilded a file which looked
> like I suspected on a large scale, but upon
> zooming in I could see that the data was pulsed
> with regular periodic silence, so that it
> sounded like a stick on a picket fence.
So here ecasound's accesses the audio hardware throurgh various layers of
ALSA (the OSS-emulation). So this could be a ALSA bug...
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