Participant

Question

25fps to 29.97fps with no duplicate frames??? How can i do this?

Forum|Forum|7 years ago
May 1, 2018
2 replies
9750 views

Ok so I have a issue at work I have a 25fps mp4, someone is asking....

"Can you please update the YouTube Frame Rate to 29.97? Can you also please confirm that there are no blended or duplicated frames?"

I've tried converting but every time it has duplicated frames, I know via after effects i can interpret footage and do it around there perhaps but I need to be told exactly what to do so no vague answers please?

Need help ASAP PLEASE

This topic has been closed for replies.

R

Rick Gerard

Community Expert

If you want to keep all the original frames in your source video you have to select the original footage in the Premiere Pro Project or the After Effects Project and select Interpret footage. You then just force the original footage to the new frame rate. Change 25 to 29.97 and you will not have any duplicate frames. The footage will run a little faster but there will be no duplicate frames.

A batter option may be to use 23.976 or 24 fps because the speed change will be less noticeable.

If you are getting judder in the movement then the problem is more speed of movement vs frame rate. Watch any old western and you'll see that the wheels on the stagecoach often turn backward. That's a perfect example of the problem. If your spiral pattern is not working the way it should then you have to change the speed or hiding the problem with motion blur. Pixel Motion Blur is probably the effect you want to try. It's not the blended frames as much as it is the speed of the motion that is causing the problem.

Maestro666

Participating Frequently

You used an example of wheels on a stage coach. I notice a jitter or jumpiness in simple movement such as walking or running when I go from 25fps to 29.97fps. So here's my issue... I am burning DVDs of files I have taking up crap tons of space on my PC. Some of them are PAL 25fps. If I want to make a DVD-R of those files, I have to make MPEG2 at 29.97fps (I will never understand why DVDs have to be 29.97fps but I am not the tech savvy one here). So I make the conversation in multiple coverter programs and the burn discs using DVD Lab Pro II. The result is the same no matter which converter I used. I get a slight jitter motion when a person walks, runs or there's a camera pan across a room or landscape. It's quite friggin annoying and I have no idea how to fix this.

Here is something else I do not understand: I have a program that allows an MPEG2 to be set at 30fps. But.... DVD Lab Pro will NOT accept 30fps, only 29.97. So... Adobe Encore will accept 30fps as MPEG2 but...and this boggles my mind being that I am NOT tech savvy... Encore will burn the disc and although the overall qualtiy is fine, the image has these weird lines in fast motion and a fuzzyness around the outline or images. I've read that this is caused by interlaced video. But.. Encore will produce the same video at 29.97fps without this fuzzy/lines effect. What changes by simply doing 30fps rather than 29.97 in Encore?

andrec98422456

Participant

Hi Maestro,

I've used Encore for hundred of projects and I import 23.98 progressive mpeg-2 DVD files rendered widescreen 720 x 480 with the 1.212 pixel dimension. I don't render to 29.97 interlaced video for the sake of making the DVD. The DVD hardware player will output an interlaced signal from the progressive file and if you're lucky to have a progressive DVD player and monitor you'll probably be about to view the 23.98 progressive file from the DVD player without the 29.97 framerate and interlacing. I've extracted files off of such DVDs and retrieve the progressive 23.98 file.

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Rick Gerard

Community Expert

You can't make extra frames without duplicating either fields or frames. Can't be done. 24fps film converted to 29.97 fps video involves a 3:2 pulldown scheme and interlacing. You would have to do something like that. The pitch change from 24 to 25 fps is not noticeable unless you have perfect pitch. I would interpret the 25fps MP4 as 23.976 then render adding interlacing and 3:2 pulldown. That will give you an interlaced 29.97fps video that looks as good as it can look.

You have two other option is to experiment with dropping the 25fps footage in a 29.97 comp and experimenting with frame blending options. The last option is to purchase Twixtor. It do a good job of predicting pixel motion and blending frames providing you set it up properly.

Personally, I think this is probably much ado about nothing. Nobody is going to see the difference between 25 and 29.97 unless there is some frame rate critical movement in the movie like rolling credits. If those kinds of elements exist then you'll have to retime them so you don't introduce Judder.

So did I help?

simonh57760236Author

Participant

This is for broadcast which means there can't be duplicated or blended frames and it needs to be 29.97 otherwise it'll fail QC, I'm fairly sure.

This is at work, for a ad agency so can't really buy Twixtor. What do you mean by duplicating fields?

I've tried your first option

R

Rick Gerard

Community Expert

There is no such thing as duplicated or blended frames when you convert 25 or 24 to 29.97. You end up with interlaced with 3:2 pulldown. If you deinterlace converted footage and deliver 29.97P footage and they step through it one frame at a time they will find blended frames.

There are systems to convert PAL to NTSC and that is what you should use. I'd just send it out. The color space, format, compression, and audio specs are more important to most broadcasters than interlaced footage. They would or rather should never ask you to provide a progressive version of a converted PAL original. It's just not done.

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