[Haskell-cafe] MIDI-controlled application

[Tim Baumgartner]

Hi Stephen,

2011/12/27 Stephen Tetley <stephen.tetley at gmail.com>

> Hi Tim
>
> More problematic is that FRP models hybrid (continuous and discrete)
> systems. For me at least, MIDI seems essentially discrete - a stream
> of control events. In MIDI files control events are twinned with a
> time stamp so they can be played. Presumably events are instantaneous
> in real-time interactive MIDI - not something I've looked at.
>

The events all feature a time stamp and my drum set produces lots of
"CRTClock" events for synchronization. I didn't use the time stamps in my
Java application but I would have to for recording/recognizing rhythms.


> Working with an FRP system like Yampa might add a lot of complexity,
> which admittedly you should be able to ignore


Yes, I'm a bit afraid of that.


> but initially it might
> be difficult to identify what parts are needed for a "mostly" discrete
> system like MIDI. (If you are time-stamping MIDI events yourself you
> will presumably need to sample a running clock which seems like a
> continuous behaviour...)
>
> Unfortunately I can't think of any systems in Haskell that are "more
> discrete than continuous" so you might have to choose a FRP system
> anyway.
>

I just had a glance at Peakachu. It seemed easier than Yampa to me. I liked
the Program abstraction. Perhaps I can use this...


> Incidentally, I've been working on a MIDI "animation language" for the
> last couple of days based on the animation language in Paul Hudak's
> book. I've wanted continuous behaviours to model modulating volumes
> (crescendos, decrescendos) and panning, but I've found the work tough
> going for modelling the note lists where I want the system discrete in
> both input (specification) and output.
>

This reminds me of the Yampa based synthesizer from the paper "Switched-On
Yampa". I just looked into it.


> Best wishes
>
> Stephen
>

Thanks
Tim
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