Talking to myself again. Not the first time though …
I finally figured out what was going on so thought I’d add to my post in case anyone else has the same problem sometime in the future.
The documentary that I’ve been working on for some time now is a real Franken-project. When it came to me, it was already a mish mash of clips of varying formats, codecs, frame rates, field order, etc. Ironic, as the film is about classic horror movies. I really wanted to start afresh by re-digitizing everything, but wasn’t allowed that option so I’ve had to work with what I had. As it was, I had to do a great deal of conversions to get 21st century editing software to cooperate. Re-digitizing in this case wouldn’t have mattered as the problem was in the old source tapes.
The edit project is set up for standard D1 specs; 720 X 486, lower fields first. The problem clip though was DV rez (720 X 480) and digitized with upper fields first. In AE, I’d set interpretation for upper but was rendering to lower to conform with the edit timeline.
When selecting a time source in AE to clone from, my normal routine is to find the glitch, position the clone brush cursor over it, hit page up to back up to 1 frame earlier, ALT click the clean spot, then page down and start painting.
As it turns out, the tape dropouts are occurring on one field, not on a full frame. If you think about how video tape is recorded, this makes prefect sense. So, with the source clip interpreting upper and the project set to render lower and backing up to an earlier time point in the AE project to clone, I was essentially canceling my efforts out. Even though it looked like it was working in the project window, the render reality was otherwise.
I eventually resolved the problem by cloning from a later time point but got to thinking how there must be a more elegant, accurate way to do what I wanted. I had a thought and dug back into an older Trish & Chris Meyer book and indirectly found a solution.
I left the source interpretation as it was but then changed the Comp settings to 2X the frame rate, namely 59.94 fps. Now when I page up or down I’m seeing each field and when I double click the source layer, it’s window also reflects this higher frame rate setting. Now when I page up and select my clone source time, I’m actually selecting from just the previous field.
When sending the comp to the render queue, I had to make sure the frame rate settings were at 29.97, but this time the rendered results were what I was expecting. Whew!
M. Whitney