By By Pradeep Ramachandran
x265 version 1.9 has now been released. This release supports many new features as well as additional assembly optimizations for Main12, intra prediction and SAO. Recently added features lookahead-slices, limit-refs and limit-modes have been enabled by default in the supported presets. Full documentation is available at http://x265.readthedocs.org
- Quant offsets: This feature allows block level quantization offsets to be specified for every frame. An API-only feature.
- intra-refresh: Keyframes can be replaced by a moving column of intra blocks in non-keyframes.
- limit-modes: Intelligently restricts mode analysis. – –max-luma and –min-luma for luma clipping, optional for HDR use-cases
- Emergency denoising is now enabled by default in very low bitrate, VBV encodes API Changes – x265_frame_stats returns many additional fields: maxCLL, maxFALL, residual energy, scenecut and latency logging
- qpfile now supports frametype ‘K” – x265 now allows CRF ratecontrol in pass N (N greater than or equal to 2)
- Chroma subsampling format YUV 4:0:0 is now fully supported and tested
Presets and Performance
- Recently added features lookahead-slices, limit-modes, limit-refs have been enabled by default for applicable presets.
- The default psy-rd strength has been increased to 2.0
- Multi-socket machines now use a single pool of threads that can work cross-socket.