ZV-1 USB streaming to iMac = no sync

[sichapm]

I've been trying to get my new ZV-1 (firmware 2.01) audio and video in sync when USB streaming to my (High Sierra) 5k iMac. Typically, using the ZV-1's inbuilt mic as the audio source, I'm getting the audio coming in 1 second ahead of the video. I get the same problem when I switch the audio source to an external USB mic or to the Mac's built-in mic.

HOWEVER, I discovered that I can always get video and sound in sync (temporarily) if I first select the external USB mic as the source and then switch back to the ZV-1 mic. In Quicktime Player I can thus make a perfect short video…but as soon as I end the recording and start a new one straight afterwards, using the same sources, the audio is again 1 second ahead of the video. This is reproducible.

In my troubleshooting steps to try to normalise the USB stream, I tried the following (none of which helped):

1. Reboot computer

2. Reboot ZV-1

3. Clean my HD with both Disk First Aid and CleanMyMac

4. Logging in to my computer with a virgin test account

5. Trying two different USB cables

6. Trying two different USB ports

7. Switching to two alternative audio sources (internal iMac mic and external USB mic)

Is there a known issue - perhaps a bug in the ZV-1 firmware? If not, what could be the explanation for the ZV-1's audio and video syncing only after switching to a different audio source and back again? Thanks for any help.

[sichapm]

@Marino.Manolo I appreciate your help but there is honestly no point. *If* Imaging Edge fixes the problem, it only gives me 1024 x 576 max, which isn't enough. It also doesn't accept audio from the ZV-1 or an external mic, forcing the use of the iMac's built-in mic which is shabby.

On those terms, I don't want to fix the problem.