Going back to the middle of last year there's been the open-source x265 project for implementing the High Efficiency Video Coding (HEVC) video format that succeds H.264/MPEG-4 AVC. We have also seen open-source HEVC / H.265 support come via libde265 as a decoder for this video format that doubles the data compression ratio of H.264 while at the same video quality level.
In September we saw VLC merge x265 support and then in October was FFmpeg's initial H.265 support via OpenHEVC. Now today both FFmpeg and libav have integrated x265 encoding support into their respective programs.
The x265 video encoding support can be enabled by building FFmpeg/Libav with the --enable-libx265 configure option. The work was done by Derek Buitenhuis and first hit FFmpeg and was immediately followed by the libav x265 encoder commit.