I have recently noticed (by tinkering with DaVinci Resolve) that some of the 30fps footage is marked as using drop frames but other 30fps footage (using the same resolution) does not. For example, on this screenshot of the DaVinci's media panel shows 2.7K (2688 x 1512) unedited videos. They are all 30fps (29.97) but the first and last is non-drop frame and in-between everything else is marked as drop frame (DF).

Anyone knows what causes one footage (of the same resolution and fps) being marked as drop frame and others are not?

Hi, osmonauta. Thank you for reaching out. Let me confirm this with our relevant team. We'll keep you posted.

Hi, osmonauta. Please check my DM regarding the topic we discussed. Thank you.

Hi, osmonauta. Please check my updated DM. Thank you.

"Hi there. Thank you for patiently waiting. Here's an update from our relevant team: It is not dropping frames, but a kind of Drop Frame timecode. To eliminate the timecode difference that shooting at 29.97fps would result in 3.6 seconds less per hour (relative to real-time), a method called DROP FRAME was developed) ; It may be related to the length of the videos. Is there any difference in the length of these videos (with DF and without DF)? Better to provide a video with a DF mark and a video without a DF mark for further check."

Thank you for the follow-up, DJI Gamora!
It doesn't have to be private message, after all there's no secret, and others might also wonder about this. I didn't imply that the frames are being dropped. I know about drop frames, after all the internet is full of articles about it. I was just curious why one footage ends up being DF and others are not.

Eg:
1. press the shutter to strat recording
2. press the shutter to stop recording
3. repeat a few times
4. some videos will end up with DF and some won't

It's not a critical issue, I thought there's a basic explanation for it.

As an example, I recorded some footage since my original post. All of them are 2.7k @ 30fps. Some ended up being marked as drop frame and some didn't. I'm sure it's happening to others as well, they just don't check it or pay attention to it. Or possibly don't even care. It doesn't really matter to me either, I was just curious.

osmonauta Posted at 4-16 05:24
"Hi there. Thank you for patiently waiting. Here's an update from our relevant team: It is not dropping frames, but a kind of Drop Frame timecode. To eliminate the timecode difference that shooting at 29.97fps would result in 3.6 seconds less per hour (relative to real-time), a method called DROP FRAME was developed) ; It may be related to the length of the videos. Is there any difference in the length of these videos (with DF and without DF)? Better to provide a video with a DF mark and a video without a DF mark for further check."

Thank you for the follow-up, DJI Gamora!

Hi, osmonauta. As mentioned in the DM, it may be related to the length of the videos. Is there any difference in the length of these videos (with DF and without DF)? Please provide a video with a DF mark and a video without a DF mark for us to further check.

It is not related to the length of the videos. The screenshot I provided shows the duration of each clip in the DURATION column.

osmonauta Posted at 4-22 07:36
It is not related to the length of the videos. The screenshot I provided shows the duration of each clip in the DURATION column.

Hello, osmonauta. Please provide us with the videos with DF tags and videos without DF tags for further confirmation.