HEVC / H.265
High Efficiency Video Coding — 4K streaming workhorse.
HEVC (H.265) is the video codec that made 4K streaming practical — about 50% more efficient than its predecessor H.264. Patent licensing complexity (multiple pools, opaque royalties) drove the industry to develop the royalty-free AV1 in parallel; HEVC remains universal as the floor codec on all modern hardware.