Subject: Re: [linux-audio-user] HDSPconf and sync
From: Lee Revell (rlrevell_AT_joe-job.com)
Date: Fri Dec 24 2004 - 21:29:46 EET
On Fri, 2004-12-24 at 12:15 -0700, Mark Knecht wrote:
> On 23 Dec 2004 21:53:34 -0800, Fernando Lopez-Lezcano
> <nando_AT_ccrma.stanford.edu> wrote:
> > On Thu, 2004-12-23 at 20:11, Kevin Ernste wrote:
> > > > Range 1 - 44.1K/48K
> > > > Range 2) 88.2K/96K
> > > >
> > > > Jack can switch between either rate in each range, but for whatever
> > > > reason it cannot switch between the two ranges themselves.
> > >
> > > Aha, this is precicely the behaviour I was looking for _across_ the
> > > two ranges! As you say, sampling rates change happily within each
> > > range, just not to/from rates in the other. In any case, I'm relieved
> > > to know that it's not my setup (things are working remarkably well
> > > now).
> > >
> > > I may contact the developer (if only to thank him) and inquire about
> > > this, it seems to me that ALSA or JACK should be able to inform
> > > HDSPconf of a rate change regardless of speed/range. It is
> > > particularily painful at the command line where I'm jumping back and
> > > forth between rates all the time meaning HDSPconf is always open ;)
> >
> > There was a thread long ago about this. I think the issue is that the
> > number of channels that the device supports change with the switch
> > between the two ranges of sampling rates. I don't remember why this was
> > a problem.
> >
> > -- Fernando
> >
> >
>
> Hi,
> Yes - there have been two or three threads about this, I think. The
> number of 'user visible' channels does change between the two ranges.
> RME 'binds' two channels running at 44.1K to make an 88.2K ADAT
> channel. The ADAT interface itself does not run at 88.2K. It's just a
> logical combination of the data on both channels to make it look like
> the card is runnign 88.2K. (Or 2x48K to make 96K)
>
> Unfortunately this is not a globally supported mode of operation
> for ADAT devices. None of the Pro Tools hardware I have supports this.
> It does work fine between RME cards though.
I also seem to recall there was some kind of an issue where you cannot
distinguish an incoming 44.1 stream for an 88.2 (or 48 from 96) stream
with half the number of channels, or something. This was either
discussed on the list, or maybe in the comments in the driver source.
Lee
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