Editing HLG 120 fps footage in final cut pro dropped footage

[mlo0its]

Hello, I currently purchased a Macbook Pro 16 (2.3ghz, 64gb RAM, 5500M 8gb, 4TB) and noticed that when i try editing 120 fps footage in final cut pro with an HLG color profile from both my sony A7 iii and a6600, while playback for the first few seconds is totally smooth, video continuously drops frames resulting is choppy video playback. just curious if this was a bug that everyone is experiencing or just my own device. In this case, my videos are saved on the internal SSD, no other programs are in the background. CPU and RAM usage are low and not close to 100%. Although, temperature skyrockets to around 75-80 degrees whereas idle, it is 35-40 degrees. I’ve isolated this to just 120fps clips shot in HLG profile. Slog clips have normal playback.

 

[Newah]

Bro! Same exact issue here. So specific but definitely some sort of glitch. The 16" Macbook is editing so slow with this kind of footage on FCPX. Premiere Pro is butter. Other footage types are fine. Help report back if you find anything else out.

 

[linyx]

After Four Weeks,Finally,I solved this problem.
If you are in 10.14 or lower system,Everything will be fine.
But if you are in 10.15 catalina,you shoud set View-Quality in the FCPX monitor from “Better Performance" to "Better Quality"
👍👍