[Fedora-music-list] ardour 2.4 was out
Dave Jones
davej at redhat.com
Wed Apr 9 22:00:34 UTC 2008
On Wed, Apr 09, 2008 at 02:40:04PM -0700, Fernando Lopez-Lezcano wrote:
> > All this said, I personally haven't hit any issues with things like MIDI in
> > Fedora where the -rt kernel would have helped me. Maybe my gear is special,
> > but latency between me hitting a key on a synth and having that note show
> > up in rosegarden, and a sound being created is well below perceivable.
>
> And that would be how many milliseconds?
I honestly couldn't say (it's been some time, and I'm a few thousand miles
from home right now).
> What could seem below the perception level to you (caveat: I don't know
> if you are a musician and what instrument you play) may bother a
> professional percussionist using the computer as an instrument. It all
> depends on your demands as a performer.
"musician" may be stretching my abilities somewhat :)
But yes, I understand that I'm probably not pushing things perhaps as
far as some others may be.
> Besides realtime performance, all the audio-over-the-network being done
> at CCRMA needs it (see: http://ccrma.stanford.edu/groups/soundwire/).
>
> This is, in a nutshell, multichannel (between 4 and 8 channels)
> non-compressed high quality bidirectional audio being sent between 2 or
> 3 geographically separate locations to create a virtual concert hall and
> jam session or concert. You don't want to add _any_ latency to the one
> that speed of light already gives us :-) We routinely run at 64 frames
> (or 128 if the links are not good). The stock Fedora kernel is just not
> good enough although I'm sure it is getting better all the time.
*nod*. A while ago, I was tempted to add the latency-tracer part of -rt
to Fedora kernels just to see what would show up, but Ingo wasn't really
interested because he felt that we'd get a lot of reports we'd already
fixed in -rt.
The fundamental changes to spinlocks is probably the real controversial
stuff that's left to go upstream. How well that goes remains to be seemn
over the coming months.
> > Right now the guys working on that stuff typically have a
> > bunch of 'boring' test cases more tailored towards replicating situations
> > like stock trades and the like. If we can construct additional use-cases
> > I'm sure Ingo, Thomas & co would be very interested to hear about them.
> > Especially if these cases are triggering different latency paths.
>
> The apps being worked on at CCRMA (jacktrip) would touch both the
> network drivers and drivers for pro audio cards. Probably disk as well
> if the same host is being used to record the performance in Ardour.
Ok, that's an interesting use-case and in honesty, I don't think it's
too different to the use-cases like the stock trading stuff that people
have been focusing on, so it's understandable why you're reaping
the same rewards.
Dave
--
http://www.codemonkey.org.uk
More information about the Fedora-music-list
mailing list