[Darryl Ramm]

Uh how can anybody guess what cameras you are talking about and what inputs they have available? And the mixer is doing what? Feeding live sound at the event as well as you want to drive a separate submix for video? Or you just want to split the main mix? The mixer has something like 3 separate stereo submixes... so in many split live/video events one of those submixes is likely recorded if you want a mix-down recorded to an outboard analog recorder. Or maybe you just want to take the main AES/EBU out or the alt main mix is on a pair of TRS jacks or... ... we can't guess.

I'm not really following the goal. Why does one camera need to take a direct feed off the mix board? If you are doing manual sync up anyhow... The QU24 has an integrated recorder, why not just record to that and then do manual sync up later? If the on camera mics are far from the source you'll have some time of flight of sound latencies to correct anyhow.

Or doing this a lot? Why not get timecode on the cameras and record LTC into the QU24? Or maybe by that point just record using an outboard recorder with digital timecode support? Timecode is getting cheaper and easier to use. Stuff to work out when you are not working on a job.