It seems a join venture of Moving Picture Experts Group and ITU-T Video Coding Experts Group currently develops a new video codes that among other things compresses twice as efficient as h264: HEVC. https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding
As h264 had real patent pressures, and thus is hard to implement with all software freedom retained: What is the status of HEVC, that is supposed to become h265 regarding patents and openness?
If the video codes of WebM: VP8 or libvpx is a real competitor to h264, what could be the next version that can compete with the claimed higher efficiency of HEVC?