PhotoJPEG Artifacts in FCP movies
 

I'm creating short animations using Jumpbacks and Artbeat background movies which are in Photo JPEG Codec. Whenever I export the movies, I get varying amounts of artifacting regardless of what sequence and render settings I use. Best results are when I export 10-bit uncompressed movies. Movies usually incorporate a JPEG or TIFF image over the motion background, but the artifacting is usually too much to use the final product.

Everything plays fine when playing with Realtime Playback, but the transitions between JPEGs, sometimes a page peel or dither dissolve can become a bit too taxing so I need to render for smooth playback. This is where the artifacting begins.

Any thoughts on eliminating the artifacts? I've tried Photo JPEG, Motion JPEG A/B, AIC, ProRES for my sequence, and they all produce less artifacting right up to 10-bit Uncompressed.