[LAU] : Netjack : like a charm :)

[torbenh at gmx.de]

On Thu, Dec 11, 2008 at 10:03:22AM +0100, Mysth-R wrote:
> 2008/12/10 <torbenh at gmx.de>
> 
> > On Wed, Dec 10, 2008 at 08:16:29AM +0100, Mysth-R wrote:
> > > * I would like to test the --celt option. But I can't understand what the
> > "N
> > > bytes per period" option are.
> >
> > it tells celt to compress one period of data to N bytes.
> > i use -c32 for internet connections generally. sounds ok.
> > if you can cope with lower quality lower it and add more channels.
> >
> > be careful to not max out the link, because this will give you netxruns.
> > using celt you will only hear a lot of them, but they degrade the
> > quality.
> >
> > > * It seems that xruns on the master computer made some
> > desynchronizations.
> >
> > oh... right this can happen.
> > i need to think about how i can fix this.
> >
> >
> > > * On seq24, on the slave computer, I had to configure the option with
> > "Jack
> > > Transport" AND "Master JACK" ... a bit disapointing... We lost so much
> > time
> > > finding this very logical configuration.
> >
> > sorry, i was not really clear about this.
> > netjack only synchronizes the frame count. not the tempo information.
> > So you need a Transport Master on both ends.
> >
> > The problem is that the slave transport is basically running in the
> > future to compensate for the latency of the network link.
> >
> > I cant know of tempo changes ahead of time. So its mostly
> > impossible, to add N frames, to beats:bars information.
> > Tempo changes would at least become flakey.
> >
> Ok but If tempo on the master is 120 and tempo on the Slave is also 120,
> should it be ok ? Would it be always synchronized after hours and hours of
> rolling ?
> Because for our needs, we don't want to change tempo while Jack is rolling.
> Just fixe it at the begining and be sur that it will not be desynchronized
> after 1 or 2 hours.Can you confirm this ?

If it looses the sync its a bug.
i will try to reproduce it with xruns on master.
there might be desynchronisation happening, when the master
xruns.

there is one case, where desync would happen, which is not
printed to the terminal.

and another which is quite deceiving:
"resync after freerun" 
this does not resync the transport. it resyncs the internal
framecnt value, resulting in desynchronisation of transport.

however i only expect these things to happen on a high latency,
packet losing link. Not on a LAN.

In any case start stop of transport would fix it, so if you have the
feeling its loosing sync, just make a musical break.

> > > * So the problem was seq24 on the slave machine was running at this own
> > > tempo. If the master use 120BPM and the Slave 110, they are not
> > > synchronized. But if you put 120 on both, it seems to be synchronized...
> > > Well I think there is a bug in seq24 or something. I didn't try with
> > other
> > > softwares. But I have some doubt about the real tempo synchronization.
> >
> > as stated, it only synchronizes the framecount.
> > netjack2 seems to do complete tempo synchronisation, but i dont know
> > if its latency compensated. and i also had somebody reporting,
> > that it just fails with an assert triggered.
> >
> > >
> > > Thank you very much for this great apps that change our lives :)
> >
> > no problem.
> > just spread the word. i still have the feeling, not many
> > people are using it :S
> 
> Yes of course ! In fact, I think not so many people are knowing the
> existence of this software. And perhaps those who know about it are a bit
> scared, ... like me at the begining... Because in my mind I though about too
> much difficulties ... how does it works ? is it easy to implement to use it
> ? In fact it was a bit obscur for me. But now I can affirm that it is very
> very easy to use it. I think I will post a bit of documentation on LinuxMao,
> the french Linux website.

cool.
> 
> >
> > while there is obviously much use for it.
> >
> Is it possible to have more than one slave ? One master and several slave
> trough local network or internet ?

yes. just start another jack_netsource.
you might want to use the -j "name" option to give it a more speaking
name. 
You can even run the jack_netsource on the slave, and slave another
slave.

But if possible use a star topology.

> By the way thank you for your precision about celt. It is not so clear in
> your website.

The website is still just building up.
And the internet stuff, still needs more testing. I was not able to
connect with someone who had hydrogen running and do tranport tests.

Note: not because it did not work, simply because i did not find anyone
      on irc, who was interested in testing transport.

> Cheers,
> Mysth-R
> 
> 
> >
> > --
> > torben Hohn
> > http://galan.sourceforge.net -- The graphical Audio language
> > _______________________________________________
> > Linux-audio-user mailing list
> > Linux-audio-user at lists.linuxaudio.org
> > http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
> >
> 
> 
> 
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-- 
torben Hohn
http://galan.sourceforge.net -- The graphical Audio language