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Title scroll flicker

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Andrei ZagdanskyTitle scroll flicker
by on Dec 30, 2009 at 10:19:37 pm

Hi -
I have a relative long credit scroll done as a Photoshop file. Painstakingly done layout.
Preparing file for FCP. PAL XDCAM EX 1080p.25
How to get rid of this flicker? I render in Prores 422.

Thanks a lot for your help.

Andrei Z.

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Dave LaRondeRe: Title scroll flicker
by on Dec 30, 2009 at 10:29:59 pm

You are seeing the effects of After Effects' ability to do subpixel rendering. As the layer moves up, After effects may move at something like 2.33876 pixels per frame, for example. The subpixel rendering lightens or darkens the tops of letters to make it look smooth, but instead it makes it look like the tops of letters move a tiny bit.

The only way to remove it may not be what you want to do: you must move the layer vertically in integer pixel increments: 1 pixel per frame, 2 pixels per frame, 3 pixels per frame, etc.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Andrei ZagdanskyRe: Title scroll flicker
by on Dec 30, 2009 at 10:40:31 pm

David, thanks.
I feel like I am a bit over the top. How I do this? Calculating number of frames per scroll?

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Dave LaRondeRe: Title scroll flicker
by on Dec 30, 2009 at 11:03:05 pm

[Andrei Zagdansky] "Calculating number of frames per scroll? "

Basically, yes.
  • Put the layer in its starting position. Make sure the layer's y-value is an even number.
  • Move the timeline cursor to the point where you think you want the roll to end, and move the layer to its ending position. It would be good if the y-value is also an even number, no fractions.
  • Subtract the y-value of the starting position from the y-value of the ending position. You now know how many pixels the layer moves vertically.
  • Divide the vertical change -- you just found out this number -- by the number of frames.

You now know the number of pixels per frame the layer moves. It's probably a fraction, but it can't be a fraction. So you have choices to make: do I make the roll a bit faster? Do I make it slower? These decisions are up to you.

I hate doing rolls like these. They are always a compromise, and they always take a lot of arithmetic before I'm done. And because I live in NTSC-Land, I have to deal with 29.97 frames/second. Ugh.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Andrei ZagdanskyRe: Title scroll flicker
by on Dec 31, 2009 at 1:21:53 am

David, thanks a lot.
Will try. I have a 25-frames advantage in my case, but still it doesn't look like a lot of fun.
will keep you posted with regards to my progress. :)

BTW, Do you know a better way to make a scroll?

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Michael SzalapskiRe: Title scroll flicker
by on Dec 31, 2009 at 2:33:03 pm

This thread from the main AE forum on the COW may help you. There are some expressions used and several suggestions given (i.e. Mercury Jones) that will probably be of use and may save you some time.

(I found the thread using the oft-neglected search feature of these forums by searching for smooth scroll or smooth credits, I forget which.)

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.

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Todd KoprivaRe: Title scroll flicker
by on Jan 1, 2010 at 6:14:10 am

There are some tips on this page that may help:

"Best practices for creating text and vector graphics for video"

Todd Kopriva, Adobe Systems Incorporated
putting the 'T' back in 'RTFM' : After Effects Help on the Web
If a page of After Effects Help answers your question, please consider rating it. If you have a tip, technique, or link to share---or if there is something that you'd like to see added or improved---please leave a comment.

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Kevin CampRe: Title scroll flicker
by on Jan 6, 2010 at 5:10:25 pm

sorry for the loss of the mercury jones preset... i found that it tended to create confusion and that a simpler approach may be easiest (i kept adding options to that preset based on requests/feedback and it just started getting a bit too complicated and created too much confusion)

here is a simple expression that will create a flicker free roll, allowing you to set the pixel/frame rate that you want:

rate = 2; //value in px/sec.
if (marker.numKeys > 0){
if (time > marker.key(1).time){
value - [0,rate*timeToFrames(time-marker.key(1).time)];
value - [0,rate*timeToFrames(time-inPoint)];

jsut position the roll where you want it to start and it will march up the screen at the rate that you set. even rate values should be used if you are rendering to an interlaced format, and if you set the rate too high the roll will appear kind of strobe-like.

you can add a layer marker to delay the roll if needed -- maybe 'the end' dissolves in and then starts rolling up the screen with the credits...

Kevin Camp
Senior Designer

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Iwantmore AndmoreRe: Title scroll flicker
by on Apr 23, 2013 at 10:59:11 am

Excellent strategy, it worked for me (pal and hdv)

BUT don`t forget to turn the field rendering on in the render queue>render settings

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