Recording multiple cameras simultaneously on a Mac

I have two webcams and a Cam Link 4K I use with my Sony a6000 for live streaming. I was wondering: is there a way I can record my two webcams and the a6000 at the same time, so I can mix the three camera feeds as a multicam clip later?

Contents:

00:00 - Intro
00:34 - Record via external cameras
01:01 - Multiple cams in one stream
01:36 - OBS hack for multiple cams
01:59 - CaptureSync
02:10 - Record with QuickTime
02:33 - Record two cams with QuickTime
04:08 - Record three cams with QuickTime
04:48 - Outtro

I know I can do it during a stream in OBS or similar streaming software, but that doesn't preserve the original source footage, so I can't re-edit the video later and choose different camera angles, or choose to do side-by-side or picture-in-picture video later.

Well, it turns out, you CAN do it on a Mac, by creating multiple copies of QuickTime Player! Check out this blog post for more info: https://www.jeffgeerling.com/blog/2020/recording-multiple-camera-angles-full-size-simultaneously-on-mac

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My main camera: https://amzn.to/2UofeBS
My webcams: https://amzn.to/2Ul9nxq

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