Can no longer import analg video via QuickTime

I have been able to import analog video via QuickTime for years:

Connect VHS/3/4" deck to DC recorder (Sony DRS11), go Firewire out from DRS11 to computer, start "New Movie Recording" in QuickTime and select DSR 11 as both audio and video source.

Since the upgrade to Ventura, QuickTime only pretends to record: it displays audio/video, the timer is running and when done, the file has the appropriate size. However, when I try to play it back, nothing has been recorded; I get a blank screen without audio or video.

I have tried a other software (iMovie, LifeFlix), always with the same result: it looks like it is recording, but it is not.

Has anyone found a solution?

Thanks,

Ingrid