Thanks Don,
Now a little error report.
http://www.users.on.net/~audionut11/0.6.mkv
Frames 2193-2214
Stepping forward through frames is fine. Stepping backwards from frame 2216 is fine. Go say 15 frames forward and then step back at speed results in frames 2193-2214 looking like the screen shot above.
Encode settings don't matter. Here is a screen shot from the same frame range using significantly different encode settings.