Hi This post is to inform users about HDR 4K video support using HEVC decoding in macOS. Hardware support Currently macOS supports software decoding on Macs with 6th gen Skylake processors, and hardware decoding on Macs with 7th gen Kabylake processors and above. Macs with Skylake processors are able to play 4K videos encoded with the Rec 709 color profile, but are not capable of smooth playback of videos using the HDR standard Rec 2020 color profile. Decoding on GPU is not currently fully supported on any Mac, but the graphics card does help with scaling. Windows does support HEVC decoding on GPU for Nvidia and AMD cards. However, Nvidia only outputs 8 bit video signals on GeForce cards. AMD supports 10 bit on all Radeon Polaris and Vega cards. macOS vs Windows support Under macOS High Sierra and above, no special settings need to be applied. HDR videos will automatically display the content correctly. Macs ship with screens supporting the P3 color profile. Any HDR videos using a wider gamut than P3 will have their color space squeezed down. This isn’t an issue in most cases. Videos will still look great. Under Windows, users must enable ‘HDR mode’ in the control panel in order to display the content correctly. Without HDR mode enabled, the video content will appear burnt out and the colors will be oversaturated. If you enable ‘HDR mode’ the Windows desktop environment will appear washed out. This mode is only suitable for HDR video content. Currently, Windows can’t automatically enable HDR mode solely when videos play. Streaming video support Neither operating system currently support streaming HDR content from popular video sources. Under macOS, HDR videos streamed from Netflix or Prime will be squeezed into the P3 color profile. This isn’t an issue unless the content uses an extremely wide gamut. Under Windows with HDR mode on, HDR videos streamed from Netflix or Prime night attempt re-enable HDR mode and freeze. Users will need to disable HDR mode. Videos will then stream correctly but use Rec 709. Currently iTunes only streams HDR content to Apple TV, so neither macOS or Windows can playback HDR content.