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Logos that scroll.... causing jittering

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Adrian Le Roux
Logos that scroll.... causing jittering
on Dec 6, 2011 at 9:18:27 am

Hi ya, I have about 20 logos that I need to scroll along the screen horizontially over the course of 10-15 secs.

When I do.... it jitters and looks NOT SMOOTH at all.... I have tried putting motion blur on it etc but still no joy.

Please help me.

Its 25fps also. No field dominance.

thanks

a

Thanks for your time.


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Kevin Camp
Re: Logos that scroll.... causing jittering
on Dec 6, 2011 at 3:33:32 pm

it would help to see a sample of the animation, but my initial feeling is that the scroll is too fast -- it would also help to know the width of the comp, the average width of the logos and the spacing between them.

to do a quick test to see if slowing the scroll rate would help, drop your current comp into a new comp that is 2 to 3 times longer (maybe 30-60 seconds). then use time stretch (layer>time>time stretch) to stretch the comp to fit the new duration.

if that helps, but you can't make this animation longer (the required duration is 10-15 sec), then another alternative would be to make the logos smaller and/or decrease the space between them... ex: if doubling the duration of the scroll helped, then halving the logo scale and space between them should help.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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Dave LaRonde
Re: Logos that scroll.... causing jittering
on Dec 6, 2011 at 4:10:11 pm

Like Kevin, I suspect you're experiencing a phenomenon known as judder, a combination of both frame rate and the amount of horizontal motion. The condition gets worse as the frame rate lowers, and 25fps is pretty darn low. Motion picture photographers have been fighting it for decades, and DP's have their own secret recipes for countering it.

If you're stuck at a certain horizontal distance to cover in a given time, just about the only thing you can do to counter it is to add motion blur, or use the force motion blur effect.

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


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Michael Szalapski
Re: Logos that scroll.... causing jittering
on Dec 6, 2011 at 8:59:44 pm

Like Kevin and Dave (welcome back, friend), this sounds like a classic case of judder! (For an example of professionals who let work go with judder, watch the opening panning shot of Cowboys & Aliens.)
See if this adds to the already good advice you've received:
Avoiding Judder in Motion Graphics
http://kb2.adobe.com/community/publishing/908/cpsid_90843.html

- 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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Angie Taylor
Re: Logos that scroll.... causing jittering #AfterEffects
on Dec 7, 2011 at 9:04:39 am

When creating scrolling text for the screen you should always make it move at an even multiple of the frame rate you're using to avoid this kind of juddering. So, if you are working in a 25 FPS comp, make it move at 50 pixels per second or 75 pixels per second to minimize the juddering effect.

Of course you could do this manually, using the Graph Editor and Info Panel as guides but much easier to use the free AutoScroll animation presets. There are two, one for scrolling vertically and another for scrolling horizontally. These should help you avoid juddering. If you still have problems, as the others mentioned, use a slight directional blur and avoid text with thin lines such as serif fonts.

Hope this helps!

cheers,

Angie

Angie Taylor animation & illustration for television, film, web and devices

http://www.angietaylor.co.uk
Twitter: theangietaylor
Linkedin: theangietaylor
http://www.facebook.com/pages/Angie-Taylor/118378194869002



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Dan Brazil
Re: Logos that scroll.... causing jittering #AfterEffects
on Jan 11, 2012 at 7:06:45 am

Thanks for this advice Angie. Just to check I understand the 'even multiples' rule OK given my recent anti judder endeavours. Specifically,in your example of running it at 75pps for a PAL comp - wouldn't that be a multiple of 3 - making it an 'odd multiple'? And would an odd multiple yield an undesirable artifact?

Mac Pro, 2x2.26 GHz Quad Core Intel Xeon, 8GB RAM


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Angie Taylor
Re: Logos that scroll.... causing jittering #AfterEffects
on Jan 11, 2012 at 8:13:05 am

Hi Dan,

My understanding of it is that it's important that it is a multiple of the frame rate. in my experience 75 pixels per second has worked for me but if you want to be 100% sure then sure, stick to an even multiple to be on the safe side.

It's important to consider the movement of the text as a value in "pixels per frame". So if your text moves by 3 whole pixels per frame that's cool. If it moves 4 pixels per frame that's cool too. What causes the "jittering" or "streaking" effect is when an object travels at 3.25 pixels per frame or 4.5 pixels per frame. It needs to move by a whole number of PPF, no fractions.

Even using these rules you may still run into problems so you can also add a little vertical blur (assuming it's a vertical scroll) to help alleviate the problems.

Another expression that might help is this one, included in a post from the wonderful Rick Gerard:

http://forums.adobe.com/thread/791530

And here's another article that may help too:

http://kb2.adobe.com/community/publishing/908/cpsid_90843.html

Hope this helps :-)

cheers,

Angie

Angie Taylor animation & illustration for television, film, web and devices

http://www.angietaylor.co.uk
Twitter: theangietaylor
Linkedin: theangietaylor
http://www.facebook.com/pages/Angie-Taylor/118378194869002



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