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Old 17th April 2024, 00:06   #1  |  Link
simple_simon
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x264 Frame Edge Smearing

Is there any way to combat the frame edge smearing in grainy video as seen here?: https://ibb.co/qg5Hjnd

Even using placebo settings don't seem to help.

x265 doesn't seem to have this issue: https://ibb.co/0cytPNm
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Old 17th April 2024, 09:33   #2  |  Link
blob2500
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I think the comparison would have been more genuine between frames of the same size.
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Old 17th April 2024, 19:54   #3  |  Link
simple_simon
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Originally Posted by blob2500 View Post
I think the comparison would have been more genuine between frames of the same size.
The 32pixel size difference wouldn't have made any difference. x264 consistently smears the right and left edges of the frame on grainy video regardless of frame size or bitrate.
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Old 19th April 2024, 20:36   #4  |  Link
simple_simon
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Has anybody else noticed this problem? Is there a solution to prevent it?
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Old 19th April 2024, 21:31   #5  |  Link
benwaggoner
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Quote:
Originally Posted by simple_simon View Post
Has anybody else noticed this problem? Is there a solution to prevent it?
Cropping to mod16 (so width and height are both divisible by 16) can help with some edge conditions like this.
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Old 20th April 2024, 04:59   #6  |  Link
simple_simon
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Quote:
Originally Posted by benwaggoner View Post
Cropping to mod16 (so width and height are both divisible by 16) can help with some edge conditions like this.
You're right, that did help a lot. I guess I had misunderstood something I had read somewhere else that leaving mod16 black bars on the edges would solve the blurriness because that didn't work. But making the total height and width mod16 did. I had to undercrop a little to achieve mod16 because the only other alternatives were to overcrop by too much or have a pretty huge aspect ratio rounding error. There's still some blurriness but not nearly as noticeable as before. I always thought not fully cropping the black borders was the thing that would hurt compression more than it not being mod16.

This seems like a pretty big flaw, I'm surprised it's never been fixed after all these years. I thought one of the benefits of x264 was that the video didn't have to conform to mod16 anymore. Interesting that x265 has seemed to overcome the problem somehow.

I guess now I have to decide whether it's worth it to have to conform to mod16 for x264 or should I just start using x265 instead despite having a much bigger gap in compatibility.
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Old 20th April 2024, 14:25   #7  |  Link
blob2500
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Quote:
Originally Posted by benwaggoner View Post
Cropping to mod16 (so width and height are both divisible by 16) can help with some edge conditions like this.
in fact, for example, I have always used mod 16, and looking through my x264 TV rips, I don't encounter this problem.

For example, in this image it should have been found, but issue isn't there:



(1248 x 672, x264 version r3153 in this case)

Last edited by blob2500; 20th April 2024 at 14:29.
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