I have a project where I am chromakeying 4 tracks each with a number of separated events on the timeline.
I am doing this through the track compositing mode...which is one way through which RED is started within Vegas.
So...I have a clip in the Vegas preview window and either start RED new through the compositing mode, or restart it via an existing compositing means on the track header. Once RED starts it does not show the video in its preview screen, rather just a blank alpha channel screen. This is even after it has opened on a previous occasion during which chromakeying had been done...
Why can I often not see my video in the preview window?