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Old 16th July 2015, 12:45   #432  |  Link
sneaker_ger
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Join Date: Dec 2002
Posts: 5,565
x264 devs always said that CRF and 2pass are roughly equal and if anything CRF has the slight upper hand. (2pass algo has to do some slight adjustments over the course of the encode to hit target while CRF is "free")

Quote:
Originally Posted by r0lZ View Post
In 2 pass mode, the second pass is slightly LONGER than the CRF pass.
No, 6.55 fps is faster than 6.16 fps. Some work (frame type decision) is already done in first pass and the whole stats calculations should be negligible compared to that so second pass is supposed to be faster than CRF.

Quote:
Originally Posted by r0lZ View Post
A very interesting information displayed after the first pass in 2-pass mode is the final ratefactor. It's the ratefactor that will be used in pass 2 to obtain the target bitrate. As you can see, in my test, it is 21.49. CRF means "Constant Rate Factor", and in my CRF test I have used 20. The CRF value of the 2-pass encoding is greater, and as you know, a greater CRF means a less good quality. (I don't know if there are other small differences between CRF mode and 2-pass, but anyway a ratefactor greater than 20 is less good than 20.)
Be careful when interpreting these values.
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