In the past two weeks, I did some test around x265 v2.4, I also wrote some post about some of results. (about “–limit-tu” and “–limit-sao”) Yesterday I fond the rip, encoding with x265 v2.4, reached 130% the size of rip with v2.3. I was considered of difference parameter, so I compared the mediainfo of the two rip, then I fond the new parameter “–no-ssim-rd”. But finally I find it has nothing to do with the increment of file size. I read…

The Definition of SAO: Sample Adaptive Offset(SAO) is a kind of in-loop filter in HEVC codec. (there are also Deblocking Filter and Adaptive Loop Filter). HEVC codec use 4×4-32×32 block size for motion-compensated prediction, while AVC only use 4×4-16×16. HEVC can also use rectangle unit(e.g. 16×4) to process prediction. The bigger unit used in encoding, the smaller file size it will be. But it can also cause more artifacts(such as Ringing). The key idea of SAO is to reduce sample distortion by first classifying…