Back in 2012 we migrated from SplitCam to ManyCam to allow continued use of our Polycom VSX7000 as a web camera. Migrating to Windows 7 and ManyCam v.4.x broke this functionality, and we held onto our Windows XP setup to give us multiple camera tools. Alas the time had come for XP to be shot and buried, but our solution was still not in sight; whenever we added the ‘AVC Compliant DV Tape Recorder/Player’ signal into the system we always received the ‘Can’t start video. Try closing other programs that might be using your webcam‘ error.
I spent way too much time trying to debug the Canopus ADVC300 – Windows 7 interactions and then swapped it out with our Canopus ADVC700 without fixing the issue. The next on the list was the Firewire card and drivers, lots of testing but still no joy. After some time I decided to try SplitCam again to see if it could pick up the camera and straight off we had an image, it seems that ManyCam v4.x was the culprit all along (note that this is *not* in their FAQ page!).
Still wanting to use some of the features in ManyCam (having paid for the ManyCam Pro version to try and solve the issues) we found it was possible to use use SplitCam v.18.104.22.168 to manage the initial video capture, this is passed onto ManyCam Pro v.4.0.77 and finally through to Skype v.22.214.171.124.
This is a tad complicated in the initial setup but once configure allows for some great tricks with multiple cameras within Skype (and webconferences).
Note: When installing SplitCam you can click on decline when it requests to install the crapware that comes bundled with it to give a clean install.