[Ardour-Dev] OSC changes/updates

Len Ovens len at ovenwerks.net
Sun May 1 16:23:38 PDT 2016

On Sun, 1 May 2016, Melanie Bernkopf wrote:

> Hello,
> yes HUI is dead but the Hardware lives on as MCP ;)

MCP is not HUI. Mackie control surfaces do emulate HUI, but it is not 
their native protocol. Ardour does not support HUI.

> Meter is for me something like this:
> http://www.sweetwater.com/images/closeup/750-MBM7CL_detail1.jpg
> and Fader is this:https://www.conrad.de/medias/global/ce/4000_4999/4400/4420/4420/442094_RB_00_FB.
> EPS.jpg
> So i think we are talking different things but meaning the same.

OSC in Ardour is meant for those, but also 

None of which use "LEDs" for anything. Level indicators are generally 0 to 
1 in floats. Meters, faders, etc. So in the long run, a meter in either dB 
or linear representation makes more sense than 8 or 12 LEDs. It is the 
control surfaces job to make something useful out of it. There are a lot 
of cheap, small arm boards out there that handle floating point math just 
fine... or can run a desktop for that matter. Touch screen tablets are all 
over, even people who don't have any other control surface have a tablet. 
So touch screen GUI based controllers are much more common.

Am I suggesting all controllers should be touch screen? no. I am saying 
that basing a protocol on a low number of reprogramable HW controllers 
over what most people use doesn't make sense.

> Those encoders give just a clockwise/counterclockwise signal so all doable in
> software with changes if lights are there well up to software. Didn´t think
> someone could think about moving them.
> Those alps fader well found them in most consoles those are even mounted in the

I do sometimes think outside of the box :) Yes that is common, encoders 
for pots like pan and motor faders for channel level. There are other 
ways, but in the end it does not matter. Any of the faders I know (GUI, 
encoder, or motor fader) have a resolution from 100 to about 1000. All of 
them can be used to accept a level change from the DAW. All of them _can_ 
be set up to provide "touch". All of them with any quick movement have a 
resolution of about 10 BTW. All of them are effectively linear. Code to 
put a nice curve from the DAW is already available. (MCP uses it and OSC 
has it available)

> On a microcontroller converting a float range from 0-2 means round it to int
> leaving me with 0 1 2 on the alps fader that would be a reading of 0 511 1023 (
> all way down, mid, all way up). Maybe i can find a mathematical way to do better
> but i have not yet searched. I have to get some testing going with PD extended to
> see if it is doable.

Multiply it as a float first. value * 1023 and then truncate anything on 
the right side of .

No floats? Do MIDI. OSC by it's nature uses floats. Any OSC controller 
that does not handle floats is crippled. MIDI is already all int. OSC will 
never be. Float is part of the OSC spec.

> And for Midi well it is in a dying state  as was the Mackie HUI once. Keeping it
> alive is not useful specially with such a limiting thing as Midi is. Let it die

A controller with no floats is just as limiting. MIDI is not dying... even 
MIDI-HD is not taking over from it. OSC is effectively static, it has not 
progressed for years because funds ran out. For this kind of control OCA 
may well take over. A $35 (or less) RPi and all the other similar boards 
out there, all do floating point math, can run an OS that allows at least 
ssh login. Can use all or any tools for software creation. Yes I have done 
projects with int only... (Old Z8 series stuff) but I wouldn't choose to 
start there now. Things like OSC assume a controller brain with more 
smarts (and memory) than that.

I am not saying it can't be done, just that it is atypical for OSC.

Len Ovens

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