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# Smooth Credits in 23.976 fps / expressions?

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 Smooth Credits in 23.976 fps / expressions? on Apr 8, 2012 at 6:55:50 pm

Hello,

I saw this covered in some old threads that seemed to only address 29.97 fps -

I am creating the text in after effects and would like to use an expression that scrolls the credits at 2 pixels a frame. My comp is at 23.976 and is 52:02 long. Any suggestions on how to apply my specs into this expression formula that Kevin Camp previously provided?

value - [2*timeToFrames(time),0]

I guess what I should admit is that I need some help with my math.. how many frames are in 52:02 at 23.976? I was guessing 1,417.

Am I on the right path? My final destination is an FCP sequence, pro res 422 HQ 1920 x 1080 23.976.

Thanks!

mac os 10.6.8
AE cs5
2.66 ghz intel duo core imac
4gb ram

 Re: Smooth Credits in 23.976 fps / expressions?on Apr 9, 2012 at 1:20:56 pm

[Brian Jahns] "I guess what I should admit is that I need some help with my math.. how many frames are in 52:02 at 23.976? I was guessing 1,417."

52 seconds and 2 frames at 23.976 frames per second is 52 * 23.976 + 2, or 1249 frames. You don't need to plug any values into Kevin's expression; you just apply the expression as is to the credit's position.

You can use the following expression to get a smooth scroll. Alt-click the position property stopwatch, and enter the following expression:
```speedPxPerFrame = 2; currentFrame = (time - inPoint)/thisComp.frameDuration; value - [0, currentFrame*speedPxPerFrame]```

Expressions are evaluated every time a frame is rendered. This expression gets the x and y positions as defined by the layer's position property, then subtracts 2 pixels from the y position for every frame that's happened since the layer's in point. You can change the speed of the roll by changing the value assigned to speedPxPerFrame.

You can also manually adjust the layer's position point to change where it will begin (just don't add keyframes to the position property -- you'll get unexpected results).

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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 Re: Smooth Credits in 23.976 fps / expressions?on Apr 9, 2012 at 5:44:21 pm

 Re: Smooth Credits in 23.976 fps / expressions?on Nov 17, 2015 at 3:22:47 am

OK! what a night this one has been!
Finally got a solution to my problems...
so:
speedPxPerFrame = 2;
currentFrame = (time - inPoint)/thisComp.frameDuration;

value - [0, currentFrame*speedPxPerFrame]

is awesome! but a bit to slow for me.
and if I fiddle with the numbers it starts flickering again.
SO:

1: Create a null and apply the expression to it

2: Parent the text and resize comp untill all the thext goes by

3: exported an uncompressed video of the text

4: Imported the whole video and time remapped it to the lenght I needed
5: turned on the frame blending option in my text video layer and my comp

its a bit of a neandrathal way of doing things but the only one that has worked flawless so far.

if you have a better expression or a little plug-in please share