Hi,

I've got a CSound script which uses the schedkwhen opcode, but
periodically fails in a rather strange way.

The setup involves using continuous controller change messages to
trigger the playing of a sound event. The program sending the
continuous controller messages sends a square wave signal, and csound
detects edges and uses these to play another instrument,using
schedkwhen. The instrument which uses schedkwhen to play the other
instrument has is set up to be played for a long duration. I've tried
various schedkwhen commands, and they all fail. some exmaples are:

schedkwhen kTrig, 0, -1, 35, 0, 0.5, kpitch
schedkwhen kTrig, 0, 4, 35, 0, 2, kpitch
schedkwhen kTrig, 0.01, 4, 35, 0, 2, kpitch

(oh why won't my machine go ping?)

This works fine most of the time, however at times, what happens is
that the event will still trigger, but amplitude will be zero. Here's
an example of the output when normal:

new alloc for instr 35:
  rtevent:         T  0.327 TT  0.327 M:    833.1   2000.0
new alloc for instr 35:
  rtevent:         T  0.740 TT  0.740 M:    832.0   2000.0
  rtevent:         T  1.148 TT  1.148 M:    307.1   2000.0
  rtevent:         T  1.561 TT  1.561 M:     41.1   2000.0
  rtevent:         T  1.928 TT  1.928 M:      0.8   2000.0
  rtevent:         T  2.341 TT  2.341 M:    471.3   2000.0

and when the problem occurs:

 rtevent:         T 29.184 TT 29.184 M:      0.0      0.0
 rtevent:         T 29.914 TT 29.914 M:      0.0      0.0
 rtevent:         T 30.644 TT 30.644 M:      0.0      0.0
... and so on

So, as I understand it, it's still scheduling the score event via
schedkwhen, but the amplitude of the event is zero (last collumn).
Once this happens, it won't start playing the sounds until you restart
csound.

One idea that i've had is that there's not enough processing time for
the instrument, seems as it's played for a short duration (0.3
seconds). I've tried optimising (via removing anything else that
CSound is doing) but this hasn't made any difference.

Has anyone else come across this problem, or can suggest any solutions
/ workarounds? This is getting quite frustrating...

Thanks,
Phil