[chuck-users] syncing computers with OSC

Kassen signal.automatique at gmail.com
Wed Jan 28 21:56:04 EST 2009


Some notes;

A remark was made about the importance of timing in dance music. I don't
think sample accuracy is mandatory there, at least not for sequencing. Even
a well implemented MIDI clock (Atari,old MPC's) will service there beyond
what most people need and MIDI is slooooow. Bad MIDI clocks may be a issue
and require work-arounds. If you can get it down to the MS range for jitter
and latency you are set, I'dsay.

Some attempts have been made to sync to sample accuracy over OSC, for
example some wavefield synthesis systems that use a cluster of computers
because more channels than a single one can take are needed (one system uses
about 800 channels so that's a real issue). I think this works with
time-stamped messages but to get hose to work you need a synced clock. That
clock will likely be synced to a networked soure as well so the benchmark
for that already has jitter. We could ask Marije Ballman for what she uses
there but I'd suspect severe degrees ove Linux tweaking might be involved
and some of it might be spoeciffic to SC.

Most modern mainstream OS's aren't even realtime so unless you go Linux with
a RT kernal no guarantees can be made at all about when messages will arrive
and I'm not even sure to what degree a RT kernal will affect TCP-ip message
processing. On top of that there is the inherent jitter caused by ChucK only
processing such info once per block/buffer and at current CPU speeds and
soundcard stats I don't think you'll be running ChucK with a block of
1sample.

In short; I'd abandon this as a goal and shoot for a situation where I
didn't notice any latency anymore, then simply go with that.

For music what you hear and don't hear is a lot more important than arbitary
yet absolute standards, IMHO.

Yours,
kas.
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