Time Compression and Expansion for MIDI???

[yogi snaps]

hey there, i'm currently running 7.4 on my Mac Dual 1 gig G4 Desktop with 1.5 gigs of ram.

I have been using pro tools for many years, but just recently discovered the usefulness of the "Grid" tool for quantizing midi etc.

I record my midi drums via my Roland V Drums.

I find my BPM and record that from the VDrum brain for roughly 5 mins as an audio track to utilize as my click.

I then recorded and 'corrected' my midi according to my 'audio' click track.

Well..since discovering the "Grid", i've been recording using the actual built in click track and found that my 'audio' click track wavers a bit.

Regardless....from my older sessions where Grid was not used, i re-opened them up and saved as a new file and set up the actual tempo and set the grid up to the BPM as per song needs.

By doing so, it either compresses or expands any / all midi on the grid.

My question: If i'm happy with an older performance of my midi drums, how can i re-align them to match up with the new actual Tempo in the Grid setting?

In other words, is there a tool similar to the time compression / expansion that is used for audio, that can also do that for midi?

The reason, is that some of the performances are really good, and i'd like to stretch them back to the proper tempo that is now established in my new 'Grid' sequence.

If i'm not explaining myself clearly, but any questions, comments or suggestions would be GREATLY appreciated.

Thanks!!

[kRokksOn]

Try using beat detective on your audio click track to create a tempo map from your performance.

Make sure your midi tracks are set to sample base instead of tick base while you create the tempo map.

Then when you´ve created the tempo map, set your midi tracks back to tick base (the little green or blue icon on the track menu) and erase the tempo map.

Your midi should move with the tempo change.

now you can use the midi quantize window to align the midi perfectly to the grid if you like.

Hope this helps.

[gdugan]

How about this:

1. With your track(s) in 'Region' view, trim the beginning of each to the first downbeat of the first bar.
2. If your performance consists of more than one MIDI track, line up the beginning of them, and, in 'Region' view, group the regions into one big region.
3. Go to the downbeat of the last bar, and trim the end.
4. In Grid Mode, use the trimmer tool to compress/expand your MIDI region to fit your new grid.