You're letting the video codec make all the decisions for bitrate allocation. Netflix tries to optimize the encoding parameters per shot/scene. from the dynam

You're letting the video codec make all the decisions for bitrate allocation. Netflix tries to optimize the encoding parameters per shot/scene. from the dynamic optimization article: - A long video sequence is split in shots ("Shots are portions of video with a relatively short duration, coming from the same camera under fairly constant lighting and environment conditions.") - Each shot is encoded multiple times with different encoding parameters, such as resolutions and qualities (QPs) - Each encode is evaluated using VMAF, which together with its bitrate produces an (R,D) point. One can convert VMAF quality to distortion using different mappings; we tested against the following two, linearly and inversely proportional mappings, which give rise to different temporal aggregation strategies, discussed in the subsequent section - The convex hull of (R,D) points for each shot is calculated. In the following example figures, distortion is inverse of (VMAF+1) - Points from the convex hull, one from each shot, are combined to create an encode for the entire video sequence by following the constant-slope principle and building end-to-end paths in a Trellis - One produces as many aggregate encodes (final operating points) by varying the slope parameter of the R-D curve as necessary in order to cover a desired bitrate/quality range - Final result is a complete R-D or rate-quality (R-Q) curve for the entire video sequence