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Old Yesterday, 19:45   #1  |  Link
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Join Date: Mar 2005
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Same crf18 for x264 and x265, means same quality?

I'm trying to get a real good file size reduction with the absolute best quality possible, using either x264 or x265 and I don't care how long it takes.

So my question is, all other settings being optimal, does the crf value practically guarantee the same image quality for both x264 and x265? (very slow encode).

Someone got a 28GB movie down to 7.4GB on x264 and 6.2GB on x265, both using crf18, but I can't compare the quality myself.
It seems to me that at crf18 both images should be the best possible for that setting, but would it be near identical?

The reason I ask is ecause I also read that x265 mainly shines in low bitrates, but when there's loads of bits to distribute like with crf18 that x264 still has the superior image quality.

Would crf18 x265 make sense over crf18 x264? Or even crf16.
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Old Yesterday, 20:24   #2  |  Link
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The crf values of x264 and x265 do not map 1:1. A crf of 18 in x264 would roughly correspond to a crf of 20 or 21 in x265. Keep in mind that x265 has many more tools to compress the image boosting its quality and lowering file sizes
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