[LAU] KVM virtual machines and jack

[torbenh]

On Mon, Dec 07, 2009 at 01:48:04AM -0600, Reuben Martin wrote:
> On Sun, Dec 6, 2009 at 4:14 AM, Patrick Shirkey
> <pshirkey at boosthardware.com> wrote:
> >
> > On 12/06/2009 03:20 PM, Reuben Martin wrote:
> >> On Sat, Dec 5, 2009 at 8:39 PM, Paul Davis<paul at linuxaudiosystems.com>  wrote:
> >>
> >>> On Sat, Dec 5, 2009 at 2:51 PM, Reuben Martin<reuben.m at gmail.com>  wrote:
> >>>
> >>>> Does anybody know if it is possible to run a guest OS under KVM and
> >>>> have the ins and outs of the virtual audio device presented to that
> >>>> OS, interface with JACK on the host linux system?
> >>>>
> >>>> I've done a little googling on this but couldn't find anything.
> >>>> (mostly because "jack" is ambiguous, and "KVM" can mean a lot of
> >>>> things)
> >>>>
> >>> unless the VM software that provides fake audio devices to the guest
> >>> OS knows about JACK internally or can be configured to use it, this is
> >>> not happening.
> >>> on the other hand, if the VM software can simply use the ALSA JACK
> >>> plugin, that could potentially work (lots and lots of latency though).
> >>>
> >>>
> >> In that case I guess my best bet would probably be to petition KVM
> >> development to add support for JACK. Currently I believe it supports
> >> ALSA, OSS, SDL and PulseAudio.
> >>
> >>
> >
> > If KVM already supports those api's then it can  be used with jack via
> > several different methods. What is the problem that you are having exactly?
> >
> 
> No problems yet. I'm putting together a new system and had thought of
> using Windows and Mac as guest VM systems under KVM for running things
> that don't exist for Linux and/or don't work well with WINE. And I
> wanted to see if anybody had tried routing the VM audio ins / outs to
> JACK rather than directly to an audio sink.
> 
> Wanted to see if anybody had seriously tried this before I gave it a go.

using netjack and the master running at -p1024 seems to be working fine.
at least when i compress the audio, and there is not too much gfx memory
transfers.

i have put a windows build of jacknone-0.4 on http://netjack.sf.net
this is basically jack-1.9.4 with qjackctl and a fixed audioadapter.
it includes netone with celt-0.7 and jack_trans2midi which generates
midi clock... so you can sync your windows apps to jack transport.


-- 
torben Hohn