The original h.264 conversion took 28:36 minutes to create and was 1,162,079,866 bytes long. Each input image was 4000×3000 and I’m creating an output video with resolution 3840×2160 by cropping it at 3/4 of the height and scaling to fit. I ran all of these tests on a set of 7,129 photos I’d captured while sailboat racing on March 24th using my GoPro Hero 3+ Black. For my tests, I left crf at the default 23. A -crf 0 would be a completely lossless conversion. I’ve been using the defaults in my previous h.264 mp4 files, which should be approximately -crf 23 and supposedly -crf 28 in h.265 is equivalent to the lower h.264 value. The -crf value effects the perceived quality. It will effect both time to create and output file size. The -preset value effects how much work is done in the compression, but shouldn’t affect the perceived quality.

According to, If I add -c:v libx265 into my existing FFmpeg command line without changing anything, I’ll get an h.265 output with the defaults of -crf 23 and -preset medium.

I decided to run some tests using my GoPro time lapse program to see how much compression I’d get versus how much extra time for encoding.įirst I had to read up on the settings for using h.265 in FFmpeg.

Ffmpeg encode h265