Midi resolution / OSC



  • I'm doing a live control of some video parameters using a midi fader, but 127 steps is too rough. Is there a way to double the resolution of a midi change? If not, I was also thinking that if it was possible to increase the resolution within Isadora that might work, but not sure how to do it - for example, multiply the midi value by 10, and then somehow smooth the values automatically as the midi clicks up. But the Smoother Actor doesn't seem to do this. Any ideas?



  • Well, I did figure out this solution - not sure if there's a better one? Smoother does work - it's just that I didn't understand the settings. Really I'd love to find a way for the values to arrive into Izzy at 16 bit, so that I have more precise control. 

    51a77c-midi_rez.jpg


  • Tech Staff

    If you are looking for higher resolution input data you probably should be considering OSC (open sound control), it offers much higher resolution.
    see: http://en.wikipedia.org/wiki/Open_Sound_Control
    and http://vjskulpture.wordpress.com/2010/01/14/basic-open-sound-control-osc-isadora-mac/



  • If you must use MIDI, then look into Pitch Bend. It is 14bit stream.

    While almost all channel voice messages assign a single data byte to a single parameter such as key # or velocity (128 values because they start with '0,' so = 2^7=128), the exception is pitch bend. If pitch bend used only 128 values, discreet steps might be heard if the bend range were large (this range is set on the instrument, not by MIDI). So the 7 non-zero bits of the first data byte (called the most significant byte or MSB) are combined with the 7 non-zero bits from the second data byte (called the least significant byte or LSB) to create a 14-bit data value, giving pitch bend data a range of 16,384 values.



  • My midi controller doesn't have a pitch bend, though certainly 14 bit is enough - I need a resolution larger then the pixel width of the projectors, and I'm needing more than a few controls at the same time. So, downloaded TouchOSC and am failing at making a connection to Izzy. Perhaps because of old OS / iOS? my ipod is 3rd gen v5.1.1 and I'm on a Macbook Pro 10.6.8. Izzy 1.3.1f02. Is everything just too outdated do you think?


  • Tech Staff

    I don't think that age is the problem. You probably have an addressing problem.
    Maybe take another look at the tutorial: http://vjskulpture.wordpress.com/2010/01/14/basic-open-sound-control-osc-isadora-mac/
    also read about the stream setup editor: http://troikatronix.com/isadora-1-3-release-notes/
    Its located in the menu: Communications->Stream Setup
    Auto detect may help ?
    This thread and video link may also help: http://ni-mate.com/vanilla/index.php?p=/discussion/12/how-to-isadora-ni-mate/p1



  • Grr. I'm getting nothing. Even the basic connection tutorial from Hexler doesn't work for me via pd-extended. Trying to do it on an ad-hoc network because I'm out of town and don't have any additional equipment with me. When I try Graham's tutorial (just on one machine since that's what I have here) I see that sending and receiving works within one patch, so it must be something with the network setup or my ipod.

    Within TouchOSC though, there are preferences for incoming and outgoing ports, but in Isadora it's only in one direction - what do you do with the other setting in TouchOSC?


  • The other question I have is about "Type Tags" - I can't find anything in the TouchOSC editor that allows the user to specify that. I'm presuming that the default presets all send these messages?


  • Tech Staff

    In isadora the OSC output address is defined in the 'OSC transmit' actor.
    The incoming address is set under Isadora Preferences->Midi/Net-> Open Sound Control Port Number

    It sounds to me like you have a problem with your adhoc network. Do you have a firewall on?



  • OK, I'm a dope - disabled Intego and incoming works perfectly. So, for the OSC transmit I use the iPod's address and the TouchOSC incoming port address? Also, is there a prefix specific to TouchOSC for the control addresses or can I keep them exactly as Izzy shows them in the stream window (/1/fader1 for example)?

    I should be able to initialize values within Izzy, have the controls in TouchOSC jump to those values when a scene is activated, and then be able to manipulate the values on my iPod - changing them in real time in Izzy?


  • OK, now I see - renumbering the ports helps. Works great in both directions!

    Now my question is whether it's possible to make a bi-directional patch, so that when you enter a scene in Isadora, the settings of that scene fade to their proper values within TouchOSC, but then you have the ability to change the values within TouchOSC. I patched the Transmit and Listener actors together, at it seem to create a jumpy feedback loop. 
    Also, I'm not sure what the /isadora/1-100 addresses are for? Is the channel number just a shortcut for the long version of the OSC address?


  • Regarding this comment:

    _Also, I'm not sure what the /isadora/1-100 addresses are for? Is the channel number just a shortcut for the long version of the OSC address?_
    That was just to give Isadora it's own set of OSC destination addresses. Some software (NI Mate, OSCulator) allow you to define your own OSC output addresses. For apps like this, you could then choose to use these "built-in" addresses.
    Best Wishes,
    Mark


  • Got it Mark, thanks - it's just taking me a while to wrap my mind around this one.

    -Rick

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