26 Jul
2003
26 Jul
'03
9:51 a.m.
Mark Knecht wrote:
This info is to help me do more debug work on a new
HDSP 9652 driver
version that I am helping to test.
Should the volume levels I hear when using the command
aplay -Dplughw:0 -r 44100 data/wave/seque~10.wav
be controlled by alsamixer?
Depends on the hardware (or the driver). Many cards have a mixer for
certain output streams and/or a master mixer, some don't. (ALSA
doesn't modify volume levels in software by default).
Also, on a multichannel card, how do I direct the
above aplay command to
a specific channel? I am finding that with this new driver the audio is
appearing on ALL channels on the card, even for a mono wave file. I think
this is a bug, but I'm not sure.
The plughw plugin automatically converts sample formats. To access the
hardware directly, use "hw:0" instead of "plughw:0", but this
won't
work if your file isn't exactly in a format supported by the hardware.
To access a subset of the channels, you can use the route plugin IIRC.
The "documentation" at
<http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html> lacks
the interesting parts, so try to search in the list archives.
HTH
Clemens