Standard Rate-Distortion Optimization (RDO) focuses on minimizing mathematical error (noise) relative to the bitrate. However, this often leads to "over-smoothing," where the encoder discards high-frequency details (like grain or fine textures) because they are computationally expensive to keep.
It keeps skin, wood, and stone looking realistic rather than airbrushed. psy-rdoq
While standard compression algorithms focus on mathematical accuracy (PSNR), psychovisual optimizations like PSY-RDOQ prioritize how the human eye actually perceives a scene. What is PSY-RDOQ? PSY-RDOQ is the "secret sauce" that allows x265
For cinema enthusiasts, keeping the original film grain is essential for an authentic look. PSY-RDOQ is the "secret sauce" that allows x265 to compete with older codecs like x264 in grain retention. this often leads to "over-smoothing
Because the algorithm is fighting to preserve detail, it may demand more bits for complex frames than standard RDO would allow. This can lead to slightly larger file sizes or bitrate spikes if the rate control is not carefully configured.