atemOSC is a open-source bridge between OSC and the Blackmagic video switchers. I wrote this Mac OS X application based on the SwitcherPanel-application coming with the SDK from Blackmagic. The Github repository includes a compiled and ready-to-run version of the application.
I added the VVOSC-framework to send and receive OSC-messages (and AMSerialPort for sending signals to a custom Arduino-tally-system I built). This enables you to control your ATEM switcher via OSC. You just need the switcher to be connected via any kind of network to your computer running atemOSC, where you specify the IP-address of your switcher, as well as an IP-address, incoming and outgoing ports for the connected OSC-device. That's it!
This enables you to create any kind of interface you'd like to use for video-switching:
iPad: With TouchOSC you can create custom interfaces for mobile devices to send OSC-messages via WiFi. I created a template for TouchOSC (included in the Github repo), so I can use the iPad for video switching. It is possible to use an iPad and the standard Blackmagic-software alongside each other, because atemOSC not only sends signals to the computer, but also receives state changes from the switcher.
MIDI-pads: There are several cheap USB-MIDI-pads out there. I bought an Icon i-PAD with a fader (I use it as T-bar) and 12 buttons (unfortunately they are drumpads without a pressure point) for switching. You can use the buttons and faders of these pads to get MIDI-signals into your computer. I use the awesome OSCulator to convert these MIDI-signals to OSC-messages. Therefore you need to set the OSC-IP-address inside atemOSC to 127.0.0.1. Another downside of my pad is the lack of MIDI-controllable LEDs to indicate the selected channel.
If you used atemOSC with any other controllers, I would love to hear you experience.