On Sun, Jun 10, 2018, at 5:53 PM, lx wrote: > hg clone https://bitbucket.org/multicoreware/x265 > cd x265 > hg checkout 0.8 According to the FFmpeg configure file: X265_BUILD >= 68 The x265 0.8 tag is probably too old, so reset to the "default" branch and avoid checking out old, unsupported tags.