Hmm...MIDI and continuous fades...brings back bad memories. MIDI CCs have only 8 bit resolution, yielding 128 values and they need to send three bytes down the wire to do this (one status byte, one byte for the CC number and one actual data byte). Most MIDI implimentations I've used only utilize these "low-resolution" controllers. I don't know how well PT supports them, but I would definately reccommend the high-resolution controllers (basically combining two CCs to make one, 16-bit CC - and 6 bytes down the wire) if you actually want good, clean, fader moves.
In addition, MIDI, being the height of 1983 technology, has a throughput of 31,250 bps. Do the math, and even assuming perfect performance, you're going to hit a wall pretty soon, especially when using multiple channels - not to mention that as a serial connection, no two CC messages can actually be sent at once, so no two messages are ever truly sync'd. You could theoretically do 16 channels with 2.5ms moves, but that's assuming an awful lot of things go right.
I don't mean to disuade you, but from my experience, anything real-time with MIDI pretty much, well, blows - no nice way to put it. If you don't need gentle fades and/or aren't using many channels of automation at once, it's probably doable, and I'd be happy to help any way I can if you decide to go forward with it.
I wonder if there isn't a better way. Weren't there some old automation systems that saved automation data multiplexed on an extra track or tracks as audio on the tape machine? They were ultimately dumped and replaced by computer-based systems because of the hassle of syncing with a tape machine, because you couldn't easily edit automation data, because it was rather inconvenient to use up valuable tape tracks, etc. Using an extra PT track is a lot easier, though, can be edited, is much more reliable, etc. Would it make any sense as a poor man's automation system?
Example idea (I'm sure someone can do better): Choose 16 (or whatever) frequencies over the audio spectrum and assign one channel to each. This audio signal gets routed to the automation system, which filters out 16 seperate signals corresponding to those frequencies. Each fader then responds to the amplitude of that signal. To write automation, all you need is 16 oscillators and something to sum them. Offline editing could be a hassle, but in a rush, you could still tweak things with an EQ over the automation data (Or, better yet, create a custom plugin, one that could even be automated from within the DAW). Need more channels? Just add another audio stream. Could even set up to automate pan, mutes, solos or whatever else you feel you need. Lots of possiblities with custom plugin programming, too.
Yeah, it's ugly. Goes to show you how much I really hate MIDI.
Anyway, just some thoughts.
- E
