Novel Motion-Compensated Spatio-Temporal Filtering Scheme for x265 Open-Source Video Encoder

There is a strong demand to decrease the video transmission bitrate without reducing visual quality [1]. The x265 encoder [2]-[4] is a popular open-source encoder, which generates bitstreams compliant with the H.265/MPEG-HEVC video coding standard [5]. Built on top of x264[6], the x265 encoder is integrated into several popular open-source frameworks, such as ffmpeg [7], GStreamer [8], and Handbrake [9]. In addition, the x265 is used by a variety of broadcast and streaming service providers who leverage the benefits of HEVC for streaming live and over-the-top (OTT) content. In addition to implementing nearly all the tools defined in HEVC, it implements many algorithmic optimizations that enable trading off encoder performance for quality [2]-[4]. The performance-critical kernels are implemented with hand-coded assembly kernels that use AVX2 and AVX-512 single instruction, multiple data instructions to improve performance on x86 CPUs. This flexible architecture of x265 makes it a popular choice for HEVC encoding for both on-premises and cloud services.