Changing the framerate to 29.97 to 59.94 fps?

[Larry4009]

So I'm trying to change the framerate on a video from 29.97 fps to 59.94 with avidemux, I've been trying to get the audio in sync, but it has failed to do so. I know there may not be a way to do this, but if there is a way, let me know. I know this is impossible to do, but I need some help here. Once again, if there is one way let me know. I doubt there is a way.

[poisondeathray]

So I'm trying to change the framerate on a video from 29.97 fps to 59.94 with avidemux, I've been trying to get the audio in sync, but it has failed to do so. I know there may not be a way to do this, but if there is a way, let me know. I know this is impossible to do, but I need some help here. Once again, if there is one way let me know. I doubt there is a way.

If you double the frame rate, but keep the same number of frames, it will play 2x the speed .

So what exactly are you trying to do and why ?

If you add duplicate frames, or add inserted blends, or inserted interpolated frames then you can keep the audio in sync

[Larry4009]

What I'm exactly trying to do is increase the framerate of some of my videos because I am making a movie with the fps as 59.94 fps, and trying to keep it in sync. Do you have any step by step instructions?

[poisondeathray]

But WHY are you doing this ?

You need to insert frames by one of those 3 methods. I don't think Avidemux can do this

You can do this in editors such NLE's such as vegas, premiere , fcp , Or avisynth (but it's a bit of a learning curve).

There are side effects to each method (you can't get more real FPS for nothing - so it won't be "real" 59.94 content, even though the FPS is 59.94.)

[poisondeathray]

To illustrate: lets just use 30fps and 60fps for this example .

You start with a 120 frame, 30fps clip . So that is 4 seconds duration because 120 frames / 30fps = 4 seconds

Changing the FPS to 60, will make it 2 seconds because 120 frames / 60 fps = 2 seconds . This is just simple math . So audio is out of sync, or you have "chipmunk" voices as it's sped up

If you double BOTH the FPS and the #frames , then 240 frames / 60 fps = 4 seconds and everything is in sync as the original . Thus you have to double the number of frames if you double the FPS




BUT - where do you get those EXTRA frames from?

1) If you just use duplicates, it will look exactly as the original in terms of motion

2) If you use blends, it will be blurry but the motion will be the same as original

3) If you use motion interpolation - it will be smoother than the original (it will approach the look of "real" 59.94 footage), but there can be weird edge morphing artifacts. It can work ok on some types of footage by fail miserably on others