[LAU] Rendering multiple midi files for mixing

[S. Massy]

All right,

Here's another installment in the never-ending questions series.

I have tracks sequenced in individual midi files meant to be rendered
using various softsynths/patches. The idea is to:
1. Send the midi data to the synth using pmidi or midish.
2. Record the output from the jack ports to disk.
3. Repeat 1 and 2 for each track.
4. Import the tracks and mix them, possibly recording live material on
   top of it.

Of these, step 2 is the tricky part. Recording the output is easy enough
with ecasound or even jackrec, but the problem is that there is a gap of
silence between the time recording is started and the time the synth
starts playing, thus making syncing the tracks a very tedious job. Is
there a simple way of recording only when audio data is coming out of
the jack ports?

I hope I'm being clear enough.

Cheers,
S.M.