Subject: Re: [linux-audio-dev] jack question
From: Andy Lo-A-Foe (andy_AT_alsaplayer.org)
Date: Fri Nov 23 2001 - 04:59:30 EET
On Wed, Nov 21, 2001 at 04:48:05PM -0500, Paul Davis wrote:
> >Can anyone confirm that the current jackd actually outputs audio?
>
> yep. myself as well as several other people have run it and heard it
> as well.
I'm guessing all the other folks had S32_LE capable hardware also?
I did some more printf debugging inside jack and noticed that the
"default" device on my setup (virgin alsa CVS, no custom
.asoundrc, Trident 4DWave NX) will happily advertise S32_LE as a
supported format, along with 16 million channels :)
The jack internals are thus setup to read/write S32_LE values to and
from my soundcard, which will of course fail misserably. Or is alsa-lib
also doing a S32_LE -> S16_LE conversion before outputting to the
hardware internally??
Either way, I still get no sound from jackd. It might simply be because
it's constantly writing near zero values ([-1 1] instead of [-32767
32768])
Reversing the S32_LE / S16_LE detection to force S16_LE operation gives
the following error/crash after a couple of seconds:
jackd: pcm.c:1928: snd_pcm_areas_copy: Assertion `frames > 0' failed.
> are you sure you have the capture input set properly in ALSA? do you
> have the mixer stuff properly set up for the PCM output stream?
Sure, arecord -f dat|aplay -f dat, produces the expected results. I've
tested this with line-in and a TV tuner as source. It does a nice
ADC->DAC pipe. I understand that running jack_simple_client should
achieve the same?!
Andy
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