[gmpi] Re: Reqs 3.8 Events - ramped events

On Tue, Dec 23, 2003 at 09:56:20PM -0500, Michael Gogins wrote:
> For the kind of event process that I have been discussing and which has
> already been implemented in some existing software, a series of point values
> is not optimal and, indeed, NOT SUFFICIENT - at least, not unless it extends
> into the future. One advantage of splines, or some other functional
> representation of music time, is that it enables an event processing plugin
> to "look ahead" a little bit, for example to generate an accompaniment that
> creates a cadence that actually synchronizes with the phrasing of a stored
> sequence.

There is no future. You can assume anything you want about the future - at
your own peril.  If all this complexity is about giving plugins a hint about
the future, then I have a problem with it.

> If GMPI provides some means of iterating over future point values of tempo
> maps or other continuous controllers, that would certainly do the job, it
> would probably be simpler to implement, and thus it may even be better that
> a functional representation. But the REQUIREMENT is to enable plugins to
> process or generate continous controllers, tempos and phrasing, or
> sub-scores that synchronize with the host's view of these data.

Here is my view (and mostly the XAP model) of a unified API:

* 'Controls' are things like parameters, but more.

* Controls are modified by timestamped events (point-value or ramped).

* Almost everything is a control - tempo, meter, note-on/note-off, parameters,
  etc.

* Controls are always optional.  If your plugin provides a TEMPO control, it
  will receive tempo events.  If it does not, it will not.  If your plugin
  provides a VOICE control, it can receive note-on/off events.

* Controls can be defined as per-voice controls.  If your plugin respects
  velocity, it can provide a VELOCITY control.  If your plugin respects
  per-voice filter control, it can provide a per-voice filter cutoff.

There really isn't a fundamental difference between tempo and any other
continuous controller.  There isn't anything special about velocity that
means it should be sent at the start of each note.  Some controls make sense
with ramped values, like TEMPO, some don't.

We've wandered OT again, but this kind of matters.

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