Question: AVCHD video from Canon C100 stuttering in FCPX 10.4
I'm having the same issue with importing AVCHD video from a Canon C100, and it started after I upgraded to FCPX 10.4. Apple needs to look into this ASAP! Periodically the video will stutter on playback, audio is fine. I've tried transcoding the media to Prores 422, but the stuttering is still there. It only happens from the AVCHD files created on the C100.
FCPX 10.4 on a Mac Pro (Late 2013)
macOS High Sierra v. 10.13 (17A405)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
AMD FirePro D700 6 GB