FPS issue during Deinterlacing


i had a quick chat with amazing Emily on deinterlacing issue and it was suggested I raise the topic here (apologies for the late reply, Emily, i was on medical leave over the weekend).

when i use Dione Dv/Tv v1/v2 to deinterlace videos and double FPS, it sometimes does wonderful job. but i came across couple recent videos where is is doubling the last frame in FPS. I suspect that the issue is that it incorrectly establishes the FPS in original video (for instance 25 when it is 23.9 and thus converts video to 50 FPS, instead of 48). It then

Case example: if my FPS is 10, then Topaz Enhance will convert it like this 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B 6A 6B 7A 7B 8A 8B 9A 9B 10A 10B 10A 10B and then continues 11A 11B etc…
it is especially disruptive when there is dynamic camera and it “plucks” the video movement. I can override this issue if i deinterlace video in Avidemux using Yadif method doubling the FPS. then i can upscale video in Topaz but:

  1. quality seems to be worse/sketchier
  2. Topaz now has double the frames to process to it doubles the processing time as well. (instead of processing 20k frames via Dione Tv, it now has to process 40k frames via Artemis)

Is there a way to fix this please?
I have uploaded the files here

Thank you very much for any help.

best regards


I seem to have another issue that could be related to the same problem.

I have a very old video source that is an mpg and probably 25 frames (interlaced) per second.
The up-scaling to 1080p is great but the video plays faster than the audio.

At first I thought the players played at 60 fps instead of 50 fps, but it could be that I only have 41.6 fps instead of 50 fps but played at 50 fps. There seems to be something with 60/50 = 1.2 ratio.

Kind regards

I recently did a deinterlacing test using the double-frame model that altered the shot to 60fps. The picture looked good, but the sound is slow and off sync. Why? And how do you fix it?

Try removing the sound using MKVToolnix from the original footage, then remux the sound again into the new footage. That’s what we use now. And the final footage will be MKV as well.

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I’m a new Topas Video AI user and am not entitled to open new questions.Since mine is related to de-interlacing I thought I’d try here. I was wondering what is the reason/advantage that the default filter is a double frame model, altering 25 fps to 50? I have done an afternoon of testing on some legacy footage and am happy with the result and am not having any issues with audio. Thanks for any light on this…

to get much smoother (close to original) motion.
Interlaced video on your TV projected to your eyes as 50/60fps due to how interlace works. if you keep it at 25/30fps , you will loose half the frames and you will get less smooth motion and in some cases a bit of jittery motion.

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Interlacing is the way that the camera cuts the frames in half to save more space. In order to fill the gaps between the lines in the frame, they double the framerate. Of course this can’t be perfect since these extra frames and lines are not real. But, this could smooth out the footage and make it more comfortable to watch.

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Thanks so much, @Akila and @viktorz3008 I appreciate your taking the time to answer. I have thousands of hours of legacy footage digitized from Umatic and Betacam. I’m so happy to have discovered Topaz. I’m doing testing and have settled on the default filter for now. It looks as though the deinterlace filter also does some noise reduction and sharpening - though maybe that’s only a result of deinterlacing- I would love a present that could combine deinterlacing with noise reduction.

Thanks again for your time!

it does. Dione DV / TV also denoise and sharpen the picture. de-interlacing by itself doesn’t remove noise nor sharpen the picture, it just convers it to progressive scan.

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In your opinion is it best then to place this new processed 50fps clip into a 50fps or a 25 fps timeline?

I don’t know what is best or not, but I can tell you what I am doing with my 25 fps interlaced videos.
I double them to 50fps as part of de-interlacing process to the level I am reworking on all my old previous videos that were de-interlaced with only 25 fps at the time, replacing them now with 50fps.