x265 is an open implementation of the new standard of video coding H.265 (or in High Efficiency Video Coding (HEVC)). The H.265 standard is logical continuation of H.264 and characterized by more effective algorithms of compression. The standard assumes approximately twofold reduction of the size of the file at identical visual quality, in comparison with H.264. The standard assumes support of high resolutions up to 8K UHD (8192×4320). The first version of the H.265 standard was published at the beginning of 2013. Because standard is published quite recently, all private realization of decode / encode software are very far from perfect (including x265).