Re: [linux-audio-dev] Midi/OSC help - Continuous controllers

On 6/28/05, Olivier Guilyardi <ml@email-addr-hidden> wrote:
> 1 - a friend of mine showed me his brand new evolution uc33 midi controller.
> He's using that with a windows-based software called "Live". I was really
> suprised to see that this software use exactly what I proposed in this thread.
> First you enter a "capture-mode", you click on some GUI widget, then you rotate
> some knob, that's it : it's assigned. I promise I never saw a such thing when I
> had exactly the same idea.
>

I think everyone would agree this is a Good Thing.

> 2 - Tonight, I went to a concert of a jazz drummer, a friend of mine. He was
> using a macintosh coupled with a midi h/w controller. He spent more time playing
> with this computer than with his drumset, but nevermind... My point is : he was
> using both the midi controller, and the screen/keyboard/mouse set, just as my
> other friend above.
>

I don't see what this has to do with anything.

> Now, here's what I consider to be a very practical consideration : there are
> many GUI enabled apps, which can't run headless. A usual way of using a midi h/w
> controller is as a add-on, not as a replacement for the screen. I'd personally
> like to use a such midi h/w as a standalone device, on stage, but nothing will
> forbid me to unplug the screen in this case...
>

Never mind headless; it might be useful to run without X (hence no
GUI) on older PCs.

> By "midi-enabling" some toolkit widgets, _many_existing_ apps would suddenly
> become compatible with these dedicated controller hardware devices. I do agree
> you that the best would be for these apps to add some midi input support, as a
> separated "View".
>
> But on the other side, what about the "capture-style" way of assigning knobs to
> widgets ? Don't you see how this is efficient ? In 1 second, what you touch on
> the controller is connected with what you see on your screen (WYTIWYS ;-).
> Still, of course, in this case you may say that these are two separated layers
> that artificially appear to be one... But what about a shortcut to couple these
> two layers, if they are to get so tight ?
>

I see no reason why this couldn't be done with an MVC-like architecture:

1. Your (MVC) Controller enters "capture mode"
2. you move a slider in your GUI whichs sends a message to the MVC Controller
3. you turn a knob on your MIDI controller, which sends a message to
the MVC controller
4. MVC controller binds the two

But I should shut up because I've never done the above.

> I believe there could exist a library with which :
> 1 - you instantiate a core object (providing the alsa midi port as an arg)
> 2 - you "attach" to some widgets : sliders, spin buttons, etc.. (note that this
> is different from extending (bloating) widgets)
> 3 - you may call a function to enter the capture-mode
> 4 - 100 % of this capture-mode is encapsulated by the library : knobs-to-widgets
> assignations are handled transparently
> 5 - there is some way to retrieve these assignations to recall them later
>

You seem to really like this idea. Why don't you just do it and see
if it works well? I have an unfounded hunch that it won't, since you
usually want your GUI running in a lower priority thread.
Received on Thu Jul 7 16:16:14 2005