Reverse-telecine 59.95fps to 24fps

[Dutchsteammachine]

I would like to edit and enhance high-quality NASA 16mm images. The best quality 16mm scans I've found online are on archive.org, as high-bitrate MXF files, 1280x720 and 59.94fps.

Like here: https://archive.org/details/Apollo-15_Onboard-Film-Mags_EE.mxf

Now the problem, the camera usually recorded at 6, 12 or 24fps.

The frame rate of the scans is 24fps.

Unfortunately, the files that were put online were telecined to 59.94fps. This is done by repeating frames, sometimes 3 to 4 times. The duplicate pattern also seems to vary.

The enhancing I want to apply requires removing all duplicates and bringing it back to the native scan frame rate. So reverse telecine to 24fps for further editing.

I played with virtualdub with someone else, and that seemed to work sometimes. But then the duplicate pattern seems to change and I got frames that repeated again. Also I tried to just export it as 24fps video file but this didn't work either, still repeating images.

Also, I exported all frames as .png files and had several programs search for duplicates, but none could do this reliably.


So my question now, does anyone have a way to do this, and help me out here? that would be great.

I got a YT channel where I upload my work as a hobbyist, basically interpolating 6 or 12fps NASA footage to 24fps for a much smoother playback. Duplicate frames cause a jerky stuttering effect.

[jagabo]

AviSynth has adaptive de-duplication filters for this.

LSmashVideoSource("Apollo-15_Onboard-Film-Mags_EE.mp4") 
#DupMC(log="dup.txt")
DeDup(threshold=2.0, maxcopies=20, maxdrops=12, log="dup.txt", times="times.txt")
AssumeFPS(9.277)

You can play around with the threshold value to get more or fewer frames. The assumed FPS was based on the number of frames remaining after removing dups.

[Selur]

okay, download here is simply to slow, but may be using sRestore might be worth a look,...

[LigH.de]

Isn't SRrestore a special filter to restore gradual blending?

And Telecine works fieldbased. If it was applied orderly, it can be reversed with IVTC, just the detection will be harder in low FPS scenes. Of course, you will get a result with one continuous frame rate, it will be 24 fps (or 23.976 first) everywhere, with double frames for 12 fps scenes and quadruple frames for 6 fps scenes. AviSynth supports only one fixed frame rate for the whole movie. And many commercial video systems need that as well. Combining identical frames and creating a Variable Frame Rate clip is something an encoder might do on its own, but that requires also a container which supports VFR video content.

I believe to remember that x265 attempts to detect duplicate frames and encode them as a combined frame. But I do not yet know details (which technique it uses to combine them, and how reliable the detection is).

[sophisticles]

I believe to remember that x265 attempts to detect duplicate frames and encode them as a combined frame. But I do not yet know details (which technique it uses to combine them, and how reliable the detection is).

That's not what it does:

https://x265.readthedocs.io/en/default/releasenotes.html

[Selur]

@LigH: yes, it is, but it also worked for me fine in a similar care where I went down to ~15fps and it removed the duplicate frames fine there. Might just have been my luck with that source, but sure is worth a look/try.

[Dutchsteammachine]

Thanks for your help everyone, i talked with somebody else on a forum yesterday and I found this workflow that correctly decimates all duplicate frames, without skipping real frames that look similar.

FFMPEG takes the raw proress422 150mb/s mxf file, takes the section I want, crops it, decimates it, and saves as lossless PNGs.

ffmpeg -ss 240 -t 250 -i "D:\Apollo\16mm\AS16\Apollo-16_Onboard-Film-Mags_BBtoT.mxf" -map 0:0 -vf mpdecimate,setpts=N/FRAME_RATE/TB,crop=960:720:156:00 "FrameOutput/frame_%05d.png"

This processes at 39/40 fps. Then I can simply import the individual frames for further editing.