MP4 export = jumpy pixels?

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Welsh Jester
Posts: 44
Joined: Mon Jun 30, 2014 1:41 am

MP4 export = jumpy pixels?

Post by Welsh Jester »

I have noticed something up with MP4 export directly from Moho, as an example i copied a shape from a project I'm working on to show what happens. It's not an issue for me because i can export to another format, like .mov animation or png and then take it into Vegas for editing. But I'm still curious why this happens. I don't think it's just my end but maybe someone can render it out and see, you only need to set it to about 120 for the end frame.

All i do is export to the only available MP4 format H.264, does not matter if i select 90 or 100 quality, it is still the same.

Here's a gif example i took from a video https://i.ibb.co/5sFgH9Z/box.gif it's zoomed in so it looks a bit blurry, but you can see it, happens mostly at the top of the shape and i think straight after the initial movement.

Here's a link to the file if anyone is interested, it's just a simple shape. http://www.filedropper.com/box_1
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slowtiger
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Re: MP4 export = jumpy pixels?

Post by slowtiger »

That's just a compression artefact.

All lossful compressions (JPG, MP4 etc) divide the image into squares and replace the real content with an approximation of its contrast frequence. Since the square borders do not line up with your artwork, misinterpretations happen. And since the frame rate at which the squares are re-calculated is not synced to your animation, you'll see flickering. This is especially visible in animation with its plain colours and defined edges.
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Welsh Jester
Posts: 44
Joined: Mon Jun 30, 2014 1:41 am

Re: MP4 export = jumpy pixels?

Post by Welsh Jester »

I haven't noticed the same (yet) if i export to png/animation and then bring it into Vegas and export as MP4 from there, only seen it happen with exporting MP4 from Moho.

But yeah it's compression artefacts i guess.

Actually I'm not even seeing it on an AVI x264 export from Moho either, literally just seems to be appearing with the direct MP4 export.. well, beats me.
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