x265: updated to 3.5

Version 3.5

New feature

Real-time VBV for ABR (Average BitRate) encodes in 窶菟ass 2 using --vbv-live-multi-pass: Improves VBV compliance with no significant impact on coding efficiency.

Enhancements to existing features

Improved hist-based scene cut algorithm: Reduces false positives by leveraging motion and scene transition info.
Support for RADL pictures at IDR scene cuts: Improves coding efficiency with no significant impact on performance.
Bidirectional scene cut aware Frame Quantizer Selection: Saves bits than forward masking with no noticeable perceptual quality difference.

API changes

Additions to x265_param structure to support the newly added features and encoder enhancements.
New x265_param options --min-vbv-fullness and --max-vbv-fullness to control min and max VBV fullness.

Bug fixes

Incorrect VBV lookahead in --analysis-load + --scale-factor.
Encoder hang when VBV is used with slices.
QP spikes in the row-level VBV rate-control when WPP enabled.
Encoder crash in --abr-ladder.

(adam)