[LAU] A list of available OSC parameters?

Ken Restivo ken at restivo.org
Mon Sep 24 02:23:59 EDT 2007


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On Mon, Sep 24, 2007 at 01:46:48AM +0200, Lars Luthman wrote:
> On Mon, 2007-09-24 at 01:29 +0200, Bengt G??rd??n wrote:
> > s??ndag 23 september 2007 22:36 skrev Arnold Krille:
> > > Am Sonntag, 23. September 2007 schrieb Ken Restivo:
> > > > Does OSC support "reflection"? i.e., is there any way in OSC to
> > > > interrogate a device and get back a list of all available parameters that
> > > > the device supports?
> > >
> > > OSC is connectionless, at least if the implementation uses udp as the
> > > transport-protocol (which most do). So there is no real way to even return
> > > values. Most apps send return-values to the host/port the query came from,
> > > but if that fails or is not handled (as the current state of ofqf...),
> > > nothing really happens.
> > 
> > If OSC ain't waiting for return packets it's not UDP:s fault. You specify 
> > destination _and_ source port in UDP just like in TCP. Ergo. You state your 
> > port that you are going to receive on. So. There's a real way to return 
> > traffic.
> 
> But not a reliable way if you are using UDP.
> 
> 

My NFS server seems to do just fine with UDP. I send it requests, I get back blocks of a file. I send it blocks of a file, I get back confirmations that they were written to disk. It's plenty reliable because it's over a local 100Mbps Ethernet connection. The higher layers of the protocol implement the connection state. 

Presumably OSC connections are over media at least as fast. I'd suppose that in 99% of cases that connection is to localhost from localhost-- not even a wire in the way. I fail to understand why OSC connections over UDP is a problem unless it is connecting to a OSC client across the world, in which case I'd have to agree that UDP wouldn't be the best choice.

Anyway, thanks for all the info on OSC. I was going to try to create a shim that would enable me to control flexibly a ton of WhySynth parameters via MIDI, but it may be easier to do that in PD using the dssi~ external.

By the way, looking through my notes, it seems I discovered several months ago a way to determine which OSC parameters are available: it's called "tcpdump -vnl -i lo", and then twiddle knobs and buttons on the DSSI synth's GUI.

*hack* cough *hack*

- -ken
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