Subject: RE: [linux-audio-user] Capture with DIGI9636 Hammerfall Light andplayback with PCI 128
From: Mark Knecht (mknecht_AT_controlnet.com)
Date: Thu May 01 2003 - 16:54:55 EEST
> On Wed, 2003-04-30 at 07:13, Steve Harris wrote:
> >
> > You cant easily because the soundblaster and RME (unless you
> have wordclocked
> > them) will be running out of sync. If you did manage to make a virtual
> > device that read from the RME and wrote to the SB you would get lots of
> > clicks and pops.
>
> Is this still an issue if all the recording is with one card and all the
> playback is through the other card? And all the playback, at least, is
> analog? I don't see where the problem would come from in that situation.
>
Paul,
I'm going to guess that the problem will be in the way the output data is
handed to the Sound Blaster. Let's say that the underlying sound system
(Alsa or whatever) is running off of the RME's clock. The data is brought
into the system using the RME clock. It gets processed in the Linux
environment using the RME clock, and it gets handed, as a block of data, to
the Sound Blaster using the RME clock. This is the problem I think. The
sound Blaster needs to have the block handed to it based on it's own clock
rate. If not, then there will be times when the SB clock comes a little bit
early and the data won't be ready to go since the RME clock hasn't happened
yet. This will result in a click.
I hope this helps.
Mark
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