Quicktime Record Screen issues

[Alienworkshoper]

I just found the quicktime option to record the screen and have been trying it with WoW during duels and battlegrounds. While it's running there is some slight lag if I have the view distance turned all the way up, but there is no lag while playing and simultaneously recording when the view distance is at 50%.

However, when I play the video, the quality is awful and the interface bars are constantly flashing. What causes this and how can it be fixed?

 

[Alienworkshoper]

echo echo echo