Nick Conway wrote: > So how do they format the velocity data? Position is limited by whatever the > pulses per revolution are but velocity can be pretty unbounded.
Hi Nick, The formatting is defined by the communication protocol. For the total control, that's MIDI, so it'll start sending "widget #FOO +1" messages when you rotate the turntable clockwise, and "widget #FOO -1" messages when you rotate the turntable counter-clockwise. As you spin it faster, it sends the messages more often, until you hit some threshold, at which point it always sends the message at its basic clock rate (maybe 100Hz?) but just increases the number instead. The powermate I mentioned earlier is sort of a special case, they have their own protocol (and the device wasn't really intended for dj mixing anyway). However, I would expect most midi controllers to behave very similarly to the total control, as described above. > Is it 7 bit? How is it scaled? I think it's either 7 or 8 bit signed, yes. It's scaled by the application, and indeed, different applications have different default sensitivities. For instance, on win32, virtual DJ is a lot more sensitive than pcdj dex is by default, and vdj's default setting is subject to overflows if you spin it too fast (causing the track to seek slowly and semirandomly, usually in the opposite direction). I don't know the answers to all of your other questions, as I only have a total control. But I'll see if I can get you some captured packet data with kmidimon when I get home from work. (Maybe someone else on list can beat me to it.) > I don't think you even necessarily need position data for a motorized jog > wheel unless you want to do output control over the wheel. Sure, I was just thinking position data would be more useful if you wanted the application to map exactly one revolution of the wheel to a specific time chunk of the media file being played. I don't know if there are any controllers out there that do that (but it would be neat if they did); I think vinyl control achieves the same goal. Mark ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Mixxx-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mixxx-devel
