I am trying to shrink some videos from 1920x1080 to 1280x720 and to achieve a reasonable compromise between video quality and file size. I have decided to give FFMPEG's H.265 encoder a try, and now would like to know which CRF value I should use to get "visually lossless" results.

I know that this term may be misleading, but I have taken it from FFMPEG's H.264 documentation. In the section about the CRF value:

Consider 17 or 18 to be visually lossless or nearly so; it should look the same or nearly the same as the input but it isn't technically lossless.

Furthermore, in FFMPEG's H.265 documentation, in the section about the CRF value:

The default is 28, and it should visually correspond to libx264 video at CRF 23, but result in about half the file size.

So I have learned that a H.265 CRF 28 should produce roughly the same visual results as a H.264 CRF 23.


Does that mean that a H.265 CRF 22 should produce roughly the same visual results as a H.264 CRF 17?

In other words, is the following statement correct: If I encode a video with H.264 with a CRF of N, do I get the same visual result if I encode the same video with H.265 with a CRF of N+5, independent of N? Or does that formula only apply for N=28 and N=23, respectively, since this is the example the FFMPEG H.265 documentation gives?


1 Answer 1


considering that in ffmpeg every +6 in crf means half the bitrate and considering that hevc is 50% more efficient than avc a crf of 23-24 will lead to visually-lossless compression in ffmpeg with libx265.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.