[aminozuur]

He is using Sony software on the iMac and Apple's own iMovie on iPhone. iMovie for macOS and iOS has always been ridiculously fast, even on a 2011 MacBook Air.

Perhaps, a better comparison would be to compare iMovie on iMac VS iMovie on iPhone 12.

[bentoBox82]

That’s one step closer, but it all depends on what exactly you want to test and compare. If you want to test raw speed you probably need to use comparable transcoders.

[artellectual]

Looks like Final Cut to me, which is Apple's software.

[aminozuur]

My bad. He said "Sony fx9 footage" and I mistook it for being the software.