29.970 to 25fps

[magnu]

I have some videos I wish to Convert from 29.970 to 25fps. I want to do so without quality loss. I have the latest version of Vegas Pro. I also have Twixtor, if that helps? I also currently have a subscription for Adobe After Effects & Media Encoder (but plan to remove them as I can’t afford it!).

I haven’t tried this before so how do I go about it? Which software is easiest and is there any free alternatives I can use instead?

I am on Windows 11.

[poisondeathray]

I have some videos I wish to Convert from 29.970 to 25fps. I want to do so without quality loss. I have the latest version of Vegas Pro. I also have Twixtor, if that helps? I also currently have a subscription for Adobe After Effects & Media Encoder (but plan to remove them as I can’t afford it!).

I haven’t tried this before so how do I go about it? Which software is easiest and is there any free alternatives I can use instead?

I am on Windows 11.

Is there any audio ?

It's not possible without loss, unless you slow it down, but then audio discrepancy is far too large (~20% slower speed...)

Think about it - if it's truly 29.97, you have to discard information to achieve 25 . You're going from a higher to a lower number. Discarding means loss.

Are you sure they are 29.97 ? Not 23.976 content with telecine (3:2 pulldown) ? If it's a theatrical content, it's likely 23.976 content. In that case you are speeding up, and that is a common situation and possible after pulldown removal (ie. "PAL speedup")

[victoriabears]

why do you want to do this?

[rrats]

You can make a 25fps sequence and then input your 29.97fps video. But you loose frames that way

[ProWo]

You could IVTC the 29.97 fps video to 23.976 fps.

[magnu]

First of all, it's a TV show and definitely in 29.97 fps. What I should have stated in my first post but forgot to mention is that I originally had the UK BluRay, which was 25fps but made a copy and then sold the original. Unfortunately, I since discovered some visual faults but couldn't get a replacement copy.
This TV show was produced for British TV and the same release came out in the USA, but with a frame change up to 29.97. I was given a copy of this version.

I know some people always say things such as why go to the bother of changing it again, but it's simply because the speed of the video is now slightly faster than the original.

I don't need to worry about the audio if I convert the video as the audio for the UK copy I made is still perfect.

PS Would going in the other direction and converting to 50fps be a better solution?

[poisondeathray]

What kind of "visual faults" ? If it was produced for British TV, then presumably it originated at 25p , and it shouldn't have problems

For the American release - it depends on how the specific conversion was done; some methods are mostly "reversible", some are not (or have other issues). The usual conversion would be 25p to 29.97i , via either field repeats or blends - but your version might have other steps applied in between

You will probably get better advice if you describe it correctly, or post a sample

[manono]

The usual conversion would be 25p to 29.97i , via either field repeats or blends - but your version might have other steps applied in between

Yes, there's these Snell and Wilcox boxes that can interpolate from 25->29.97fps. I have no idea how one would undo that kind of conversion. But then, nor can I understand how and why the video would be speeded up in the process, as magnu claims. And it's still the same length as the original so the audio fits them both?

Anyway, as you suggest, a sample is needed so it can be examined.

[DB83]

I am still struggling with the rationale in attempting this.

In my rapidly-reducing-brain if the 29.97 fps version is running faster than the original 25 fps then whoever converted it simply changed the frame-rate and (what has not been mentioned) the frame size. Surely 25 fps for a blu-ray suggests legacy SD frame size of 720*576 for 25 fps and 720*480 for 29.97.


That being so then by simply reversing the process and re-sampling the frame-rate back to 25 fps - but still having regard to the frame size - will 'fix' the issue.


I am probably over-simplifying the issue since such an initial re-sampling from 25 fps to 29.97 will alter the run-length. But would the reverse restore the original run-length or create timing issues which would mean that the original audio could not be used.


But I must concur with those that know much more about these than I do. We need an actual extract. Maybe one from both the original 25 fps copy and the 29.97 fps derrivative. If the OP does not know how to do these (I would hope given his existance here that he does) then we can guide him forward.

[magnu]

The visual faults were basically that I made my original conversions on a setting that was far too compressed for the actual video, making it seem like it was skipping frames and also the occasional blocky artifacts.

I shall try to put up an example soon.

[rrats]

Send a sample.

[magnu]

I have decided not to bother with the converting. However, everyone here seems desperate for me to send samples, yet I don't see the point in doing so, as I really just want to hear a straightforward answer to my question, regardless of what videos I plan to work on since there are so many people who always seem to say things that are completely irrelevant to questions being asked on many forums that we visit.

So really I would just like to know a simple answer to my question, even though I may not necessarily follow the process through? It seems a bit silly to me when I see responses to questions all over this site along the lines of waste of time, etc...

No one on here has said that though, but I thought I'd just bring that up as I am curious still as to the various possible methods used, considering this is meant to be a helpful site for video editing, viewing, and so much more.

[DB83]

I thought it was quite clear.

It was explained t you that various methods exist to do the conversion. The purpose of the sample was to attempt to establish the method used which would then, in turn, provide the best solution.


Go to a doctor and he asks you for 'a sample'. Then he can diagnose the problem and not simply guess.

[magnu]

Read the first line in my post. I am not talking about one specific video. I thought that was made clear?

[hello_hello]

magnu,
If you have multiple (unrelated) videos you'd need to provide multiple samples. One from each video, in case it wasn't clear they could have been frame rate converted in different ways.

I have some old DVDs of classic Doctor Who converted to NTSC. For those, the 25fps video sections were converted to interlaced 29.97fps using some kind of interpolation process (fine on an interlaced display, a bit ugly on a progressive display, and irreversible either way), while the progressive film sections were converted with field blending (can be reversed). I've seen progressive BBC video that appears to have been slowed from 25fps to 23.976fps with audio pitch correction (and could then have standard pulldown applied for 29.97fps). I'm pretty sure I've seen progressive 25fps converted to progressive 29.97fps using the type of interpolation process manono referred to above (probably irreversible but it looks very good), and progressive 25fps is often converted to interlaced NTSC by slowing it to 24.975fps and repeating every fifth field for 59.94i (can be reversed).

I don't recall ever seeing a 25fps video converted to 29.97fps that resulted in it being sped it up. 25fps to 29.97fps is too large a difference. The above techniques either slow the video down slightly or keep the durations the same. Naturally there's more frames after a conversion to 29.97fps, but the video durations are either the same or slightly increased, so your question is probably based on an incorrect assumption to begin with, but there's no way to tell without a sample......

[DB83]

Read the first line in my post. I am not talking about one specific video. I thought that was made clear?

Sure you mentioned the plural "videos".


Yet you later elaborated and talked about a tv series on blu-ray. Would anyone think that different episodes from that series be converted from 25 fps (if they really (originally) were) to 29.97 fps in a different way. So we have to take the series as a whole.


You mentioned "time wasting". Your topic smells of that. If you really wanted help you would appreciate the help suggested.


Copy a BD set and sell it.Then get a another set as a 'gift'. Do me a friggin' favour. We were not born yesterday.

[davexnet]

For a quick and dirty, just use

ConvertFPS(25)

in Avisynth and be done with it

It may or may not be acceptable

[LigH.de]

If you want to learn basics and technical background: StainlessS translated a guide to English, originally written by scharfis_brain in German - "exotic Interlacing"