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Choppy horizontal animation

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Sofia Svensson
Choppy horizontal animation
on Jan 28, 2010 at 4:04:04 pm

Keeping my fingers crossed that someone here can help me shed some light on this problem:
Been tearing my hair out trying to get a plane with a banner to fly smoothly from left to right. The plane is composed of two transparent PNGs. One of the plane, and the other is a comp with the PNG banner in it with a wave effect applied to it.

The animation looks pretty okay when it's being played on my PC. (Flawless at 60 fps) However, it looks very choppy when it's being played back on a powerful HD media extender type of device. The latter is similar to a PC, so I don't know why its playback is worse.

I've tried changing the frame rate to everything I can think of. 29.97 fps seems to work with the least choppyness. But still noticably choppy. 60 fps, unfortunately, is worse.

Can you think of anything that would give me better odds for a smoother flight?

I've come across expressions that are supposed to match the speed of what you're animating to your frame rate. Sounds like a good idea but I haven't managed to find a legible description on how exactly to do it.

Any hits or tips deeply appreciated!


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David Johnson
Re: Choppy horizontal animation
on Jan 28, 2010 at 5:12:03 pm

Maybe I'm misunderstanding the issue, but it seems you've left out the two factors that are more important to the playback you get than the types of files you used to make your animation or its frame rate ... with what settings did you render the output file (codec, screen size, etc.) and how are you playing it back (via a desktop media player, burned to DVD and played on a DVD player, etc.)?

In other words, from this statement, it sounds like the issue is not with your animation or file, but with the method by which you're viewing it ...

[Sofia Svensson] "The animation looks pretty okay when it's being played on my PC. (Flawless at 60 fps)"


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Sofia Svensson
Re: Choppy horizontal animation
on Jan 29, 2010 at 8:23:29 am

Thanks for your reply!

The problem very well could be with the media extender. However, I don't understand why that should be - since it's playing other files I've created in the same way flawlessly.

Here are some more specs:
I've tried both 1024x576 and 1280x720 (makes no difference)
The animation is rendered with render settings: best settings and Output module: lossless.
Finally I've tried to compress it with a bunch of different codecs that ususally work for me, like DivX, XVid etc. These too make no difference whichever I choose.

This is why I only included the info about frame rate, since it's the only factor I've tweaked so far that's made any noticable difference.

Thanks again for your reply.


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Robert Paynter
Re: Choppy horizontal animation
on Jan 30, 2010 at 3:37:38 pm

Is motion blur on? Is it possible you need to open up the shutter angle on your camera? (Under the advanced tab in comp settings)


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David Johnson
Re: Choppy horizontal animation
on Jan 31, 2010 at 1:18:43 am

I've used custom render settings and output modules for so long I don't recall what the default settings are, but the "best" and "lossless" settings very likely make uncompressed video files, which most computers would have trouble playing smoothly. That would be compounded by the large screen sizes you mentioned.

Both of those issues are further compounded when files are played from a drive that isn't fast enough or through a drive connection that isn't fast enough. I'm not familiar with a "media extender", but it sounds like some type of proprietary external drive. The smoothness of video file playback is very dependent on the read speed of the drive and the speed of the connection its tied to the computer with (whether internal or external).

Try putting the animation on DVD or tape to confirm whether the "chopiness" is an issue with the file itself or the playback method since the latter is a very common issue ... in other words, if you try to play an uncompressed video file on a regular computer, it'll play back choppy, but there is nothing wrong with the file.

Also, are you sure there are no differences between other files you've had success with and your current animation? Obviously the content is different so I'm just talking about specs (codecs, frame rate, screen size, etc.). Eliminating any possible differences should help figure out why you're getting different playback results.


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Sofia Svensson
Re: Choppy horizontal animation
on Feb 2, 2010 at 9:57:05 am

Thanks for your reply. Perhaps I failed to mention that I've compressed the final comp. Uncompressed footage would indeed cause the problems you mentioned.

"Media extender" is the European term for a TIVO-like device which is used for recording and playing video files. (AVI, MKV etc) They are, in general, very powerful and can play full HD material. As is the device I'm using. It's perhaps even more powerful than the PC I'm using... which is playing the movie without these issues.

Like I mentioned earlier; I've created many movies for this particular device before. This is the first time I'm experiencing these sort of issues. I enterpreted them as some sort of error I've made in the animation or some kind of frame rate glitch. (Seeing how I've created much more demanding animations before without having these problems... and the rest of the animation runs smoothly.) It's just the darn plane that won't fly smoothly. *lol*

I give up. Maybe it's a flaw in the monitor hooked up to the media extender. Or even a driver glitch connected to the graphics card in the media extender. Who knows?

Seeing how you guys haven't thought of anything major I could have done wrong... I feel pretty confident that it's the device that's acting up and not the animation itself.

Thanks again for your replies! :-)


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Dave LaRonde
Re: Choppy horizontal animation
on Feb 2, 2010 at 4:13:50 pm

[Sofia Svensson] "The animation looks pretty okay when it's being played on my PC. (Flawless at 60 fps) However, it looks very choppy when it's being played back on a powerful HD media extender type of device....
"Media extender" is the European term for a TIVO-like device which is used for recording and playing video files. (AVI, MKV etc) They are, in general, very powerful and can play full HD material. As is the device I'm using."


It sounds like you're having a "judder" issue -- that's a poorly-defined term for horizontal motion that looks more like a series of discrete stills rather smooth motion, and it manifests itself at lower frame rates.

The preview looked good at 60fps... but I bet that Media Extender plays at 25fps. As a test, what happens if you alter the speed of that horizontal move?

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


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