Apple's upcoming macOS Big Sur update appears to enable 4K video streams encoded using the HEVC codec, delivering Safari support for popular platforms like Netflix.
During beta testing, Agarwal was served a 4K stream with Dolby Vision while viewing Netflix content on Safari in Big Sur. Dolby Vision is a branded HDR technology used by a variety of video streaming and on demand services to deliver content tailored to high-resolution screens.
Apple currently provides support for both 4K and Dolby Vision on iOS and Apple TV 4K, though access on Mac and macOS is restricted due to software limitations. As it stands, Mac is relegated to 1080p Netflix streams, though Dolby Vision is supported for select content. That will apparently change when Big Sur arrives this fall.