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.