Hi. Slow editing in timeline only of HD (1080i HD 29.97i, Stereo) video on tape captured in Final Cut Pro X. It does not allow the files to be transcoded to "Create optimized media" (click box in light gray, not an option). SD video from tape and all non tape acquired video (HD to 4K) edits fine. Arrow keys for micro forward and backward movement of edit point marker on timeline very slow. When you move the edit point marker in the timeline and press the space bar to start playback you get the spinning rainbow wheel for a while and if you go to Force Quit you will see (not responding) in red writing next to Final Cut Pro X. Ideas? Thank you.