Ok, so I went into Media Manager and duplicated my project, recompressing into ProRes 422. I can now edit in RT (thanks!) but only at about a frame per second. Out of curiosity, I examined the media files that Media Manager created– they are still MP4s, and Final Cut still identifies them in Item Properties as having H.264 for a compressor. So I went back and grabbed one of my original MP4s, threw it in Compressor and recompressed it as a ProRes MOV. Then I reimported this into Final Cut and threw some filters on it, and it was able to play back at full framerate.
I’m not sure what Compressor did differently than Media Manager, but it certainly works better. If I just convert all my MP4s with Compressor, should I be able to easily take my old media offline and reconnect it to the converted files? Or is there a way to get more control over Media Manager’s recompression?
Thanks for the help!