Export Glitches: One Black Frame?

Wayne-McIlvaine wrote on 5/10/2025, 7:48 AM

I have been noticing these single black frames appearing during transitions between two clips over the past few months. They do not appear in the Timeline Preview - only appear in the final export.

I believe they manifest themselves because of some bug in the software: sometimes I am unable to drag the beginning of a clip to the end of the previous clip while editing. Nothing I do allows me to do anything but overlap the two clips for a "blend" / "fade" and whatever is blocking me from dragging the beginning to the end (i.e. forcing the overlap / blend), causes these single black frames in the exported video.

Look specifically at 12 seconds into the attached video, and 36 seconds in.

What do you think is causing this, and how can I fix it?

Thank you!!

Comments

AAProds wrote on 5/10/2025, 8:07 AM

@Wayne-McIlvaine

It could be...

Zoom in to frame level and check the ending frame finishes exactly on a whole frame number. Sometimes files end at a point mid-frame eg at a half frame past the last full frame point.

Here's an example. The left video (CCTV camera) ends at midframe, and the right video cannot be dragged to a butt-join; it has to be an overlap.

The solution is to trim off the end of the left video so that it ends on a whole-frame point; in this case, put the Play marker on 00:00:12:00 and cut the delete the offending part frame, then join the two videos up as you normally would.

Wayne-McIlvaine wrote on 5/10/2025, 9:10 AM

@Wayne-McIlvaine

It could be...

Zoom in to frame level and check the ending frame finishes exactly on a whole frame number. Sometimes files end at a point mid-frame eg at a half frame past the last full frame point.

Here's an example. The left video (CCTV camera) ends at midframe, and the right video cannot be dragged to a butt-join; it has to be an overlap.

The solution is to trim off the end of the left video so that it ends on a whole-frame point; in this case, put the Play marker on 00:00:12:00 and cut the delete the offending part frame, then join the two videos up as you normally would.

This sounds extremely promising. I will try it and reply soon.

Thank you!!

AAProds wrote on 5/10/2025, 10:19 AM

For the eagle-eyed out there, these videos are coming in at "approximately" 14.92fps. 😉😂

Gid wrote on 5/10/2025, 11:00 AM

@Wayne-McIlvaine Although I agree a half frame will/could cause a black frame the curious part for me is that the black frame isn't on the crossfade, it's before, the video loops the final part before the transition.

Here it is slowed down

Maybe a variable frame rate issue because you've speeded the clips up..🤷‍♂️?