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# Very small movie interpolation problem (16 pixel by 9 pixels)

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 Very small movie interpolation problem (16 pixel by 9 pixels) on Dec 10, 2010 at 2:42:56 pm

Hi all!

I'm having a problem with creating tiny movies. I'm trying to make a 16 pixels by 9 pixels movie, with a single white pixel line moving one pixel per frame.
The problem is that whenever I render the movie, it results in the line being interpolated, sometime taking up 2 pixels with various greys.
I'm not using any compression, all the values are pixel accurate, no motion blur or frame blending or whatever options I think could be the problem...

Any clues on how to get the required results?

p.s. for those wondering, I'm trying to use these movies as 'control values' for a matrix in Max (Jitter). That's why I'm making tiny movies ;)

 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 10, 2010 at 3:49:03 pm

Hi.
I've set up a project as described.
I created a single pixel white layer, which due to its size was grey instead of white, collapsed transformation, duplicated 10 times. (to make it white) precomped. animated one line per frame. seems fine.

seán

 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 10, 2010 at 10:31:43 pm

[Brecht Debackere] "whenever I render the movie, it results in the line being interpolated, sometime taking up 2 pixels with various greys. "

You can attribute that to AE's subpixel rendering. You don't mention a time duration for this tiny-little animation. I suspect you put a keyframe at the beginning, a keyframe at the end, and thought you were done. But on each frame, AE is a calculating intermediate positions for this line and it won't always be precisely over the pixels.

If I were you, I would pick a duration in frames for the movie that's divisible by either 16 or 9, depending on the direction in which the line animates. If it's moving across 16 pixels, and you want zippy-fast motion, you set the comp's duration to 16 frames. If you want something slower, you might set the comp's duration to 160 frames.

Animate this line -- a solid that's just one pixel high -- using Hold Keyframes -- that's important: use hold keyframes. In the 160 frame example, you would move the line by 1 pixel every 10 frames. When done, the line will instantly move to the next position precisely over the pixels in 10-frame increments. Heck, it's only 16 keyframes, it's easy to do. You just have to use a little arithmetic. If that's beyond you, why are you fooling around with computers in the first place?

Try it: it's the never-fail method. The only thing you might have to tweak is the anchor point of the solid, but that's a piece of cake.

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

 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 13, 2010 at 2:19:44 am

What version of After Effects? What format are you exporting to?

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 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 13, 2010 at 4:25:21 am

[Todd Kopriva] "What version of After Effects? What format are you exporting to?"

Okay, educate me if you would, sir. I don't see why the AE version would make a difference. I could do what I described in AE 3.1.

Format? Codec? That's a different story.

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

 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 13, 2010 at 5:51:46 am

> Okay, educate me if you would, sir. I don't see why the AE version would make a difference.

Here are some threads that go into some details about new output module constraints and how they affect very small AVI files:

So, if someone is trying to make very small AVI files with After Effects CS5, there may be some problems.

For example.

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 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Dec 13, 2010 at 5:56:16 pm

Thanks, Todd. Why am I not surprised that it's all about the deadlines?

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

 Re: Very small movie interpolation problem (16 pixel by 9 pixels)on Jan 10, 2011 at 5:07:21 pm

Hi all,

Thanks for the replies. I've been doing things a little differently, so the AE solution kind of moved to the background.

To answer some of the questions: I'm using AE CS4, I've put a keyframe on every frame, the line moves 1 pixel every keyframe, so no interpolation happening there. To be sure I also used 'hold' keyframes.
Codecs: I tried several, uncompressed, animation, photoJPG, and several others, so the problem wasn't that.
I'm making quicktime movies, not .AVI, so I don't think the problem described on the adobe forum applies. I'll try making a 32 pixel minimum size version anyways, just to check.