I have a sequence set at 1920x1080 with an editing timebase of 23.98 fps. I have been cutting in footage from a clip that is 59.94 fps and about half the time getting dropped frames on playback. The other half of the time, footage from this same clip is cut in and plays back in real time just fine. I have messed around with the playback options (safe RT, unlimited RT, full and dynamic quality frame rate playback, etc) and the problem clips remain jerky. Nor do I think it's a processor issue: I am running Snow Leopard on a new 8-core Mac Pro with 12 gigs of RAM.
The annoying workaround I've come up with is to cut in a section of the clip that plays back okay, then slide the clip back in time to where I wanted the original edit to be. But I don't see why FCP should have a problem playing back different pieces of footage from the same clip. Is this just FCP's generally junky way of handling mixed frame rates?
Thanks for getting back Zane. The clip is a DVC PRO HD codec 720p60. I'm using a 4 TB G-Raid external drive for the project and the media, connected by firewire 800. I should also mention that I have tried transcoding the clip to Apple Pro Res 422, but frames continue to drop in certain sections.
It is a mixed format sequence that configured itself based on the codec of other XD HD clips that I am using. There's a wide range of clips with different codecs (including some SD footage) that are native to FCP and playing back fine.
When mixing codecs NEVER use a GOP codec as the sequence codec. All the non-GOP formats, or even GOP formats with different structures (HDV in an XDCAM sequence) will cause HUGE issues. GOP native formats are processor intensive, and now you want to make a non-GOP format fit in there.
No no no.
Use a ProRes sequence setting. Even if nothing you have is ProRes....if you mix formats, use a ProRes setting. That will greatly reduce, if not eliminate, dropped frames in your sequences.