x265 source code is written in
C++ and
x86 assembly. of HEVC (including intra-only profiles), utilizing a
bit depth of either 8 bits or 10 bits per sample
YCbCr with 4:2:0, 4:2:2 or 4:4:4
chroma subsampling. x265 supports most of the features of x264 including all rate control modes: Constant QP (CQP), Constant Rate Factor (CRF), Average Bit Rate (ABR), 2-pass or multi-pass and
video buffering verifier rate control. Visual quality algorithms include CU-Tree (the successor to x264's macroblock-tree), adaptive quantization, b-pyramid, weighted prediction and psycho-visual optimizations (psy-rd and psy-rdoq). A fully lossless mode is also supported. Temporal scalability is supported, allowing for a video to be encoded into a base layer HEVC bitstream that is half the frame rate of the input video frame rate, and an enhancement layer that can be decoded along with the base layer to enable playback at the full frame rate. In April 2015, at the
NAB Show in
Las Vegas, MulticoreWare demonstrated high quality real-time 4K 10-bit HEVC encoding at frame rates in excess of 60 FPS on a dual Intel Xeon E5 v3 server, occupying only one standard rack unit. == Quality and efficiency ==