I have an app that uses AVFoundation to read and analyze frame-by-frame a *.mov file. The app, last built in 2015, would not run on my 2013 Powerbook on macOS 10.14.1, so I tried it on a iMac running 10.13.3. Often, but not always, the app would hang after reading about 26,750 frames from a ~54,000 frame video file. It wouldn't quit, it just hung. At least once, Terminal didn't respond to a control-C abort.
When I tried rebuilding and debugging on Xcode 10, I got a burst of console warnings at about frame 26,750. Most were of the form
GVA warning: addNewReferenceEntry_MMCO mmcoFunc1 not found requested 11, curr = 12
or
GVA warning: addNewReferenceEntry_MMCO force release 7
where the first version also had 16,17 and 0,1 as the arguments
and the second version also had release of 5 and 1
Subsequent files would be processed correctly, with no warnings.
Any clue what is producing these warnings, and what I can do to prevent them?