I found this explanation of Xiph.org's Daala (2013) very interesting and enlightening in terms of understanding video encoding: https://xiph.org/daala/ https://

I found this explanation of Xiph.org's Daala (2013) very interesting and enlightening in terms of understanding video encoding: https://xiph.org/daala/ https://xiph.org/daala/ Related: BPG is an open source lossless format for images that uses HEVC under the hood, and is generally better than PNG across the board: http://bellard.org/bpg/ http://bellard.org/bpg/ For a runner-up lossless image format unencumbered by H265 patents (completely libre), try http://flif.info/ http://flif.info/.