[Steve Adams]

Mads: Yes! That helps a lot! Thank you very much for that information. By the way, also relevant, I thought, was a comment from Grok:

“Frame
sampling (duplicates) and Optical Flow (synthesized frames) live in preview
renders and the export pipeline, not the source clip. Changing Interpret
Footage does not delete them from a file that never contained them. If you want the original frames and original
speed use “Use Frame Rate from File” and
then on the timeline clip set Speed/Duration to 100%.” – Steve Adams

[Steve Adams]

Thank you!

[Steve Adams]

By “target track” I assume you mean the track that is receiving the images. I don’t know what you mean by “set properly.”

[Steve Adams]

Actually, the iPhone had nothing to do with this hum, and the 1080P video it generated was gorgeous.

[Steve Adams]

Yes, what you say makes sense. I’m sure the iPhone speaker can’t produce 60Hz, so, of course, the video sounded great played back on the iPhone. It’s puzzling, though, that I didn’t notice any hum when I was following her around the store but in the video playback the hum dominates the audio. And at one point the hum disappears for about 5 seconds and then comes back on! There must be some machine in the area that gets turned on and off.

Thanks for the input.

[Steve Adams]

Ok, I think I understand the options. I just thought there might be something in Premier that could do it that I wasn’t aware of, but clearly not. Thanks.

[Steve Adams]

Thanks to everyone for the replies. The clip is about 5 minutes.

I don’t really want to become an expert in new software to do this if I can help it, so I’m probably limited to whatever I can squeeze out of PPRO CC2017. One thought I had was to maybe play with the Lumitri HSL Secondary by cranking the exposure and contrast up to a ridiculous amount, first, where I could detect some difference if indeed the eyes are actually open, and then map that color to white and finally take the exposure and contrast back down.

[Steve Adams]

I just wanted to post a follow up. I dug through ffmpeg and I was able to remove my duplicate frames. The final command was:

ffmpeg -i cut.mp4 -vf mpdecimate,setpts=N/24/TB -vsync vfr cut_p.mp4

I ran into two problems along the way:

1. MP4, by default, is a constant frame-rate muxer in ffmpeg, so timestamp gaps created by mpdecimate removing duplicates will be plugged back in by duplicate frames. The solution is to set variable frame-rate mode with -vsync vfr.

2. I had to retime the frames after removing the duplicates to get them to play at 24fps, using setpts=N/24/TB.

Thanks

[Steve Adams]

The frame rate is 24 fps. But I’m not dealing with a well-behaved clip, here, where something like a 3:2 pull down for the entire clip would do anything sensible. There are just parts of this clip where suddenly a frame is repeated 4 or 5 times and then it goes along fine for several seconds and the same thing will occur again. So it seems that what I need is something that decides when a frame is the same as the previous frame, and removes it – period. Fps doesn’t have much to do with it.

I’ve stepped through the clip manually with PP, frame by frame, and removed the duplicates and the result is what I want. I just don’t want to do it manually.

I found a Stack Overflow article on removing duplicate frames with ffmpeg at

https://stackoverflow.com/questions/37088517/ffmpeg-remove-sequentially-duplicate-frames .

This suggests that something like

ffmpeg -i in.mkv -vf mpdecimate out.mkv
ffmpeg -i in.mkv -vf decimate=cycle=6,setpts=N/25/TB out.mkv

might work, though I’m not sure yet what the various parameters mean.

[Steve Adams]

Thanks. I looked at the first two but didn’t find anything about removing duplicates. Is it perhaps a filter? Could you maybe point me a little closer to the command that removes duplicates?

Thanks