Odd problem here. I have been making extensive use of the new facility of V12 that allows Boris compositions to 'see' up to six video layers below it. This is great for creating editable multi-stream effects but I have hit a snag.
I had one layer of video with sync sound and over it (amongst many) were a number of compositions that looked at that video layer. When manually rendering each composition everything works fine, but if I batch render the compositions the video is out of sync.
What seems to be happening is that Boris re-starts the video stream rather than picking it up at the right point. As I said this has only happened when batch rendering.
So is this a known bug, my bad luck, or something that can be worked around (without the obvious 'render manually' and don't build your effects this way ;-) ) ?