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Posted: 22 Dec 2007, 17:57
by antwan
Hi,

After a long pause in investigations I'm battling with Midi clock and MMC issues again. I had serious difficulties when using the existing Midi Clock in / out add-ons.
So, I started to build my own midi clock out patch:

Image

I'm sending the midi clock and MMC messages out to a MPC1000 drum sequencer.

The construction in the image above works quite nicely to start with. The only thing is, the sync drifts within a matter of a couple of minutes. My suspicion is that it's got something to do with accuracy. Both the precise time -module and dividing the bar duration by 96 give values with decimals. The Div -module gives out integers for the Has changed for triggering the clock. So I think somewhere along the line, this could be more accurate?
Any ideas - you math geniouses - how do I get this to be more accurate so it keeps sync better? Or where's the problem?

On a side note, two questions:
- Was there talk of Midi clock being built-in into Usine? Is that near-future?
- I was experimenting with receiving and filtering MMC messages through Midi In. The Start/Stop/Continue filters in the Midi Filter module did not recognize the corresponding button presses from the MPC1000. Yet if I connected a sysex editor to the Midi in I could see the incoming messages were typical MMC sysex codes:

It gave:
[ F0 7F 7F 06 02 F7 ] -- Start
[ F0 7F 7F 06 03 F7 ] -- Continue
[ F0 7F 7F 06 01 F7 ] -- Stop

Why don't the corresponding Midi Filters recognize these button presses?

Thanks a million,
wish you all happy holidays.

antwan

Posted: 22 Dec 2007, 18:12
by senso
few comments
the next version of Usine (arrive soon) will contain basics MIDI Clocks send& receive patches.
I spent a lot of time to improve the accuracy of the tempo detection: gives a result with the best precision we can have with the midi resolution (around 0,5 to 0.1 BPM)

The MMC commands are handled directly in Usine (see setup/midi in)

so the messages
[ F0 7F 7F 06 02 F7 ] -- Start
[ F0 7F 7F 06 03 F7 ] -- Continue
[ F0 7F 7F 06 01 F7 ] -- Stop

aren't what we call 'midi messages' but MMC sysex. That why they are not filtered with the Midi Filter. If you want to catch those messages you have to use sysex flow.

Posted: 22 Dec 2007, 18:56
by antwan
Hello,

thanks a lot for your quick reply.
Ok, I will gladly wait for the new version.
I also noticed that the slave device has great difficulties keeping sync when tempo is changed. There must be some special programming in Live and other similar hosts because the same problem doesn't exist there. Have you perhaps been working on this challenge as well?

About the MMC sysex's... Thanks for the clarification.
What would be the recommended way to detect these certain sysex messages because I don't want to use the built-in MMC system in Setup, I want to handle the sysex commands differently...?

thanks olivier,

antwan

Posted: 22 Dec 2007, 19:44
by senso
you will see the patch soon. A little complex, especially to ignore fluctuations. But gives good results (?)

you catch sysex msg you can use the sysex editor
Create a patch like:

if the sysex from the midi input module = the sysex in the sysex editor
then do something.
Normally should be simple (?)