Problem solved, by the most responsive tech support I’ve ever encountered. Usually I have to wait days, Blackmagic got back to me in a couple of hours, on a Saturday. Wow.
Anyway, in case it’s of use to anybody, here’s what fixed it:
2. Reinstall the BMD drivers:
If you are having problems with Final Cut Pro HD and your Decklink card:
1. Uninstall the Decklink software. The Decklink Uninstaller is “hidden”
in the Installer folder that you downloaded from the Support area of the
Blackmagic Design Website. (You will find it at the very bottom of the
folder, all the way over to the right. It is “hidden” so that people do not
inadvertently rid the system of the Decklink drivers.)
2. Repair your Disk Permissions on the System Drive of your Macintosh.
If you have never repaired disk permissions, this may be a somewhat lengthy
process. You will find the Disk Utility in the Applications
Folder>Utilities>Disk Utilities. Repair Permissions is one of the Tabs.
3. Close all applications and shut the computer off. You will restart it
soon. But you are to shut it off so that no power is going to the system
and the cards installed in the system.
4. Now restart your system and find the folder with the Decklink
Installer software. Install the Decklink installer.
5. Repair your Permissions again. Now it should be easy to find the Disk
Utility and it should repair Permissions in no time.
6. Shut down your computer one more time and wait about 15 seconds before
turning it on.
7. Restart your computer. Load Final Cut Pro. In over 90% of the time,
this will fix any Final Cut Pro issues with regard to resolution, time code,
audio, and or sync issues.
8. Note that the Easy setups have been prepared for you so that all of
the appropriate settings are correctly configured. Changing any portion on
your own may mis-configure the setting and may create problems for you.
9. Rarely you will find that you will have to throw away your preferences
and relaunch Final Cut Pro. That was an older method of “cleaning up” FCP,
but today, repairing permissions usually solves any internal FCO
“confusion.” On that rare occasion when you might have to “trash” your
preferences, you might want to go through steps 1 through 7 again.