Daala: A Perceptually-Driven Next Generation Video Codec
  The Daala project is a royalty-free video codec that attempts to compete with the best patent-encumbered codecs. Part of our strategy is to replace core tools of traditional video codecs with alternative approaches, many of them designed to take perceptual aspects into account, rather than optimizing for simple metrics like PSNR. This paper documents some of our experiences with these tools, which ones worked and which did not, and what we've learned from them. The result is a codec which compares favorably with HEVC on still images, and is on a path to do so for video as well. 
Thomas J. Daede, Nathan E. Egge, Jean-Marc Valin, Guillaume Martres,   Timothy B. Terriberry
cs.MM