Encoder enhancements
--------------------
1. Enhancements to TU selection algorithm with early-outs for improved speed; use :option:`--limit-tu` to exercise.
2. New motion search method SEA (Successive Elimination Algorithm) supported now as :option: `--me` 4
3. Bit-stream optimizations to improve fields in PPS and SPS for bit-rate savings through :option:`--[no-]opt-qp-pps`, :option:`--[no-]opt-ref-list-length-pps`, and :option:`--[no-]multi-pass-opt-rps`.
4. Enabled using VBV constraints when encoding without WPP.
5. All param options dumped in SEI packet in bitstream when info selected.
6. x265 now supports POWERPC-based systems. Several key functions also have optimized ALTIVEC kernels.
performance oriented, with heavy improvements for AVX2 capable platforms
(Haswell and later Intel CPUs) and work efficiency improvements for
multiple-socket machines.
* encoder: emit an Active Parameter Sets SEI in stream headers if interlaced
* encoder: give more warnings when features are automatically disabled
* api: allow --psy-rdoq values up to 50; it can be beneficial for film grain
* docs: improve --pmode documentation, the feature is fully functional
* analysis: do not allow top-skip and depth earlyout in --pmode with --rd 5/6
* asm: correct wrong index name
* docs: update preset table and various command line options
* fix rd=0,1
* analysis: fix for --rd 0, do not assume a CU is only inter or intra
* analysis: rect cost compare typo fix for pmode
* search: ensure RDOQ entropy state is always initialized for chroma intra
