I am trying to edit 720p mov video footage in Pitivi, and when I place 1 clip in the timeline it plays fine in realtime. The problem begins when I add another clip and try to edit. Besides the 1st clip (that continues to run in realtime), all the other clips or cuts are choppy. I currently have 3gigs of ram and an Intel duo core processor. And using 10.10. Is there something I can try? I've heard of Kdenlive, is it better that Pitivi in handling 720p footage? Thank you very much!