Zenith432 - 2011-09-07

QuickTime works on OS 10.7, and renders video purely in software [on the CPU, no GPU assistance]. As such, it is highly susceptible to performance issues. If your host system is under-resourced, or overloaded it may perform badly. I tried QT, and it worked reasonably, but I used a small window, and didn't have much else running.
iTunes & VLC on OS 10.7 use QE/CI, which isn't supported so they show up with black screen.
Video recording in QT may not work due to the way the accelerator works. Try booting with "vmw_options_fb=3" in your boot-args do disable the accelerator, and see if QT can record video. Performance of regular graphics may suffer as a result.