Error 15 MIDI Input Buffer Overflow

Bome Products
32

Hi Steve and Florian,

My second try at solving the Error 15 issue seems to be very promising. It’s very much along the lines that both of you have been describing.

Originally, if I scrubbed a fader quickly, and update the LEDs as shown below the APC eventually freezes.

  • MT Pro Input from AKAI APC track volume fader: B1 pp qq
  • Response from MT Pro (output to Live track volume fader): B1 pp qq
  • and
  • Response from MT Pro (output to APC) for updating LEDs:
  • — 90 52 00 90 53 00 90 54 00 90 55 00 90 56 00 90 57 00 90 58 00 90 59 00 90 ss 01
  • — Where ss is the LED I want to turn on. All LEDs are turned off before turning ss on

Not so elegant, I know, but I didn\'t have enough globals to remember LED positions for all 20 tracks and didn\'t have the appetite for trying a bit mapped solution.

I think the problem may stem both from the fact that messages are sent back to the APC repeatedly during scrubbing (127 times for each stroke up and another 127 times for each stroke down). as well as from our original conjecture - that it might be due to the fact that the APC fader is moving while it is receiving LED related MIDI.

The solution seems to be:

  • MT Pro Input from AKAI APC track volume fader: B1 pp qq
  • Response from MT Pro (output to Live track volume fader): B1 pp qq
  • and
  • Response from MT Pro: Timer 1 OUT (initial delay 20ms)
  • Response when Timer 1 elapses (out to APC)
  • — 90 52 00 90 53 00 90 54 00 90 55 00 90 56 00 90 57 00 90 58 00 90 59 00 90 ss 01
  • — Where ss is the LED I want to turn on. All LEDs are turned off before turning ss on

The timer only produces output to the LEDs once (if the fader is moved fairly quickly) or just a few times for a typical, slower, movement of the fader. I think both of you had pointed out to me that the MIDI stream would be dramatically reduced… and it is.

The same fader movement produces several other outputs, some of which sent LED messages to the APC’s. I’ve taken steps to throttle the MIDI flow there too.

Anyway, I’ve rewritten the code for one of the APCs and it seems to be preventing freezing. I’ll test more extensively tomorrow, and if it really does work, I’ll rewrite for all 8 APCs and let you know how it goes.

Thanks,

Gabriel