Frame rate is likely to be 25fps/25Hz - Mac monitor may well be a 60Hz or multiple of. So the jitter may be frame rate conversion of 25/50Hz to 60Hz.

I don't know if you can change the Mac hardware frame rate for playback of these? 25/50/75/100Hz should help if you have those options available to you. My Macbook and ext monitor is locked down to 60Hz, so its not anything that I know how to do. I suspect if these were played through a normal TV they would playback smoothly.

hth

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).