FCP Video flicker problem

I'm having an odd problem with FCP.

Occasionaly when I try to play video on my sequences I am getting a flicker problem.. It's only sometimes though and I can get rid of it usualy be clicking the viewer and then back to the canvas or by refreshing the A/V devices. Unfortunately it tends to always happen when the client is in the room though. Any ideas why? This occurs both in D1 and HD sequences and both in 29.97 and 23.98 fps sequences. I have been using the Photo - JPEG codec because I am getting clips from a VFX house in that codec. Do you think its an issue with the codec? Or some bug in the program? Just really odd cause it only hapens sporadicaly.

I stand to correction but should you not rather be using a codec that matches your video clips, rather than your graphics clips - what format did you shoot in? Alternatively, if all the footage is from VFX, then it may be better to go for a ProResHD timeline?

Marcus T
iCreate! digital|post
12 Core Mac Pro, Snow Leopard, FCP 7.0.3, 8Gb Memory.

The video clips are quicktime files that are also in the photo-jpeg codec. I was sticking with that codec so i didnt need to render everytime I add a new clip.

Wow, that's a new one to me.. even so, why not try to work in one of the ProResHD codecs.. they're great..

Marcus T
iCreate! digital|post
12 Core Mac Pro, Snow Leopard, FCP 7.0.3, 8Gb Memory.