I'm using TouchOSC daily and it works really well.

For most of the buttons (push buttons, not toggles or sliders) we use "Control Change" midi messages, and it's the channel and number values which are important. The range (0-127) is not, in fact vMix ignores it so you can't use a control change for a toggle button.

vMix does not ignore the range with sliders, so "Control Change" messages can be used for volume controls for example, but even here you don't need to adjust the range settings. Just leave them as 0 and 127, and vMix maps this to 0-100%. (The range 0-127 is a midi thing by the way. See this: http://stackoverflow.com...es-midi-offer-127-notes)

For buttons which toggle, we use a midi "Note" message type because vMix will detect if the note is on or off. We use this for muting audio channels for example.

When you're editing your layout in TouchOSC Editor, you add a button and then click on "MIDI" so that you can configure the midi message that is sent when the button is pressed.

As I say, for most cases, selecting a message type of "Control Change" is what you need. But if you want to use a Toggle button with two states, you need to use a midi message type of "Note".

So in the first image, you can see the midi settings for the button I have selected, and in the second, you can see the mute button for the first audio channel which is a toggle.