Topic: "Fix" for videos with resampled framerates?

If you take a video that was originally 25fps but was encoded at 30fps, then every 5 frames you will have a doubled frame.  A 24fps video encoded at 30fps is similar.

This isn't too too noticable vs a native 25fps video if you're displaying them on a 60hz display anyway, but if you're running them through SVP @ 90fps then heck yeah is the judder noticable.


Also relevent would be 25fps content resampled to 24fps where a frame has been removed, where once every second you can have a small sudden jump fowards during pans or the like.


Would it be possible to have some sort of "fix" in SVP for such a thing, whether it's automatic or manual?

  • MAG79
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Re: "Fix" for videos with resampled framerates?

Nintendo Maniac 64
It is telecine.
25 original frames in every 30 fps is named 2:3:2:3:2 pulldown.
24 original frames in every 30 fps is named 3:2 pulldown.

The task is make progressive frames first if it is field-based pulldown. Then frame decimation is needed.
See it in pictures from Russian thread.

For avisinth you can use script with using TIVTC plugin:
To restore 24 fps from 30 fps:

TFM()
TDecimate(cycle=5)

To restore 25 fps from 30 fps:

TFM()
TDecimate(cycle=6)

You can encode fixed video from telecined version. Then watch restored version with SVP.

Re: "Fix" for videos with resampled framerates?

That's great and all, but I was hoping to look for a solution without re-encoding since apparently Sony Vegas can do a similar thing...

  • MAG79
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Re: "Fix" for videos with resampled framerates?

Frames decimating and SVP at realtime. I tried it in 2011. With no success.
At present time we have one very similar option and it works: Drop every other frame.
So. New option with frame decimation have all chances to be implemented. Look forward.
I will try to do something at this issue.

5 Reply by Nintendo Maniac 64 (edited by Nintendo Maniac 64 09-04-2015 08:09:51)

Re: "Fix" for videos with resampled framerates?

It should noted however that a 25fps source that's been resampled to 24fps via dropping a frame can't really be solved via avisynth and/or re-encoding since the solution would involve interpolating an extra frame in an attempt to re-create the dropped frame.

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Re: "Fix" for videos with resampled framerates?

Nintendo Maniac 64
Of course. And 24 from 25 restore in real time with ffdShow can be not so successful since it will want 25 frames buffer ahead for only this operation. It can be incompatible to multithreading and its frames buffer ahead and it can be harmful to audio synchronization with video.

First I will try to implement restoration two types only: 25 from 30 frames and 24 from 30 frames.

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Re: "Fix" for videos with resampled framerates?

Nintendo Maniac 64
Can you give a link to sample with 25 fps in 30 fps encoded video?

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Re: "Fix" for videos with resampled framerates?

MAG79 wrote:

Nintendo Maniac 64
Can you give a link to sample with 25 fps in 30 fps encoded video?

Take your pick:
https://www.reddit.com/r/FormulaE/wiki/howtowatch

AFAIK, all the YouTube links on that page are 25fps source video encoded at 30fps.

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Re: "Fix" for videos with resampled framerates?

Nintendo Maniac 64
Something is wrong. I checked first two links. It is true 25 fps.
1. Race

720p: Video: MPEG4 Video (H264) 1280x720 25fps 2504kbps
1080p: Video: VP90 1920x1080 25fps

1. Race Highlights

720p: Video: MPEG4 Video (H264) 1280x720 25fps 2834kbps
1080p: Video: VP90 1920x1080 25fps

Where I can get 25 in 30 fps? hmm

10 Reply by Nintendo Maniac 64 (edited by Nintendo Maniac 64 11-04-2015 03:09:39)

Re: "Fix" for videos with resampled framerates?

Interesting, I just went through every single video and it seems that different sessions are recorded/uploaded from different sources, so some have native 25fps and others have 25--in->30fps...

Anyway, all of the qualifyings are 25--in->30fps as are all the races other than the first 2 races.


Oh, another thing to mention that I thought of: 30/60--in->24fps and even 30/60--in->25fps; these are something you find with videogame footage at times.

The first 5 videos in the following playlist are an example of 60--in->24fps:
https://www.youtube.com/playlist?list=P … OlFcdZKiZE

Every single video on this following playlist is an example of 60--in->25fps:
https://www.youtube.com/playlist?list=P … ZZaKE6uR7O


EDIT: Is suggesting a "fix" for 20--in->30fps a bit too much?  A good example of this is the two Zelda games on the N64 where they only rendered at 20fps in-game (though menus and splash-screens were 30fps).

Example gameplay video showing that every other frame is doubled:
https://www.youtube.com/watch?v=3BUjR5MG3Ho


And I'd like to make a special mention of 24--in->30fps since I unfortunately don't have any example videos at this time, but it's definitely something I've run across more than I like.

11 Reply by Nintendo Maniac 64 (edited by Nintendo Maniac 64 15-04-2015 19:50:23)

Re: "Fix" for videos with resampled framerates?

Apologies for double-posting, but I just came accross a 24--in->25fps video.  I never mentioned such a thing because I didn't think it would actually exist, but it would seem that I was wrong.

Example:
https://www.youtube.com/watch?v=2i-t0C7RQWM