This indicates 4K resolution (3840 x 2160 pixels), offering four times the resolution of standard Full HD (1080p). This ensures that subtle details in the ruined reactor, the Soviet-era decay, and the characters' faces are exceptionally sharp. UHD: Ultra High Definition.
: Stands for High Dynamic Range , providing better contrast and a wider range of brightness and color. chernobyls012160puhdblurayx26510bithdrmem
x265 (HEVC - High Efficiency Video Coding), which provides high-quality video with better compression than older codecs. This indicates 4K resolution (3840 x 2160 pixels),