I read that the new H265 is supposed to have around twice the compression efficiency of H264 and supposed files around half the size http://x265.org/hevc-h265/ All of my results trying to encode to H265 give me larger files than H264 from the same source.

For H264 I am passing these switches to ffmpeg command line

-c:v libx264 -preset:v veryslow -profile:v high -crf 15 -pix_fmt yuvj420p -an -y -r 30

For H265 I am using these switches

-c:v libx265 -preset:v veryslow -crf 15 -an -y -r 30

In all tests using a variety of different source frames the H265 always results in a larger file size (and is also much much slower to encode).

Any tips for H265? I want the H265 to look like the same quality as H264 but not result in larger files.



x265 crf values are different from x264


The CRF of 28 should visually correspond to libx264 video at CRF 23

try adjusting the crf for x265 for a higher value , like 20

  • Thanks. Knowing the CRFs do not relate is the key. A CRF of 25 for H265 looks fine compared to a CRF of 15 for H264.
    – Some1Else
    Feb 17 '16 at 21:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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