Hi alsa people,
OK, this is probably in the dumb green user category of question but we
are all there at some
time or other ! Nothing in the archives seems to help.
Background:
I am writing a simple linux application which uses a professional
multichannel soundcard: envy24
Originally parts of this program were done under windows, but things
were getting real messy with
the standard windows API when you need more than 2 channels capture.
Alsa 0.9 seems to fit the
bill perfectly, allowing 96000 sample rate on 4 channels with 24 bit
sampling, and even in & out
sync !
Where I'm at:
alsa 0.9.0rc2 has been installed sucessfully. aplay works, evny24control
(wonderful!!) works.
Also, if I only playback from my application, it works (as long as I use
plughw:0.0)
Problem 1:
When I try to record I get segmentation fault in
"snd_pcm_route_convert1_one" called indirectly
by my "snd_pcm_readn" call. I would prefer to use readn rather than
readi since it suits my
application better. The capture is opened in blocking mode (whereas my
playback was opened in
non-blocking mode).
It is possible I have misinterpreted the parameters for "snd_pcm_readn",
but the API doco doesn't
describe "void **bufs" very well. I have assumed I am meant to pass a
pointer to an array of
pointers (array size = #channels configured), which in turn point to
buffers (one for each channel)
each which must be at least as big as ("size" *
#bytes-needed-to-store-sample) bytes. In this current
test I am using 16bit samples, but I'm using the "snd_pcm_format_width"
anyway. I have assumed the
buffers for the channels do not need to be contigueous with each other.
Is this correct ?
Problem 2:
When I try device "hw:0.0" the very first hardware parameter set fails
with unavailable. It's
snd_pcm_hw_params_set_access(handle, params,
SND_PCM_ACCESS_RW_NONINTERLEAVED); that fails.
I have seen other posts talking about using non-interleaved frames....
surely the ice1712
supports this ??
--
Cheers,
Bruce
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