Most tablets, phones, televisions, and streaming dongles / set top boxes require no extra setup to work in HDR, but many / most laptops & desktops do. Ensure that HDR is enabled on the device for the attached HDR display:
On Apple MacOS devices manufactured within the last three years with integrated displays, or that have an attached Apple ProDisplay XDR display, MacOS will automatically adapt played back HDR content to the native colorspace and brightness of the display without any user input and without changing any settings. No additional configuration should be required.
On all other Apple MacOS devices, navigate to your MacOS System Preferences → Display preferences. In the "Arrangement" tab, disable screen mirroring. On the "Display" tab on the pop up on your HDR display, select "High Dynamic Range". Your desktop experience on that display will adjust to operate in HDR, and color rendering of HDR content will bypass Apple's HDR to SDR conversion and render in HDR on your display. Override the HDR signaling if necessary (see Known Issues below).
Then, using Apple Safari, Google Chrome, or Opera (do NOT use Firefox), move the browser window to the HDR display, log in, and open the video page. HDR should automatically be detected and activated (see Overriding HDR Auto-detection below).
See Apple's HDR help document for more information on watching HDR on MacOS.
On Windows 10 / 11
Right click on your desktop and select "Display Settings", or click on your Windows menu, search for "Settings" and open the Settings app. In the Display pane of the settings, toggle the slider "Use HDR" to "On" under the heading "Windows HD Color". On older versions of Windows 10 you may find the toggle under the "Windows HD Color settings" link under the same heading.
Then, using Microsoft Edge, Google Chrome, or Opera (do NOT use Firefox), move the browser window to the HDR display, log in, and open the video page. HDR should automatically be detected and activated (see Overriding HDR Auto-detection below).
Note: SDR rendering from HDR content under Windows is very gross. Do not playback the HDR on an SDR display.
See Microsoft's Windows HDR help document for more information on watching HDR on Windows 10 / 11.
On iOS & Android
iOS 14.1+ has native HDR support. Devices with OLED screens (iPhone X, XS, XS Max, 11, 11 Pro Max, 12, 12 Mini, 12 Pro, 12 Pro Max, 13 Mini, 13, 13 Pro, 13 Pro Max) and Zone Array displays (the 2021 iPad Pro 12.9" with Liquid Retina XDR Display) will render the HDR content with exceptional quality. iOS devices with standard LCD screens, including other versions of the iPad and iPad Pro have high quality HDR rendering delivered by Apple's incredible color science and HDR playback support.
Many Android-powered phones and tablets support HDR, at a variety of quality levels. Unfortunately, because of the fragmented ecosystem, it is impossible for me to even begin to test and write up a help document for all Android devices. Generally, Android has supported HDR since Android Version 7.0 (Nougat).
Using Apple Safari, Google Chrome, or Opera (do NOT use Firefox, or Puffin browsers), log in, and open the video page. HDR should automatically be detected and activated (see Overriding HDR Auto-detection below). You will need to manually select your playback quality settings on iOS. To change video streaming settings, pause and exit full-frame video playback, select the video icon in the bottom-right corner of the video player, and select your streaming video quality. Lowest quality streams in 720p @ 2.5-3 Mbps, Highest Quality streams in 1080p @ 12.5 - 13 Mbps. Default is 1080p @ 5.5 - 6Mbps.
See Apple's iOS HDR help document for more information on watching HDR on iOS. See Android's HDR on Android document for more information on watching HDR on Android devices.
On Android TV & Amazon Fire TV
The current version of the AndroidTV Browser API does NOT support HDR video playback, even if the streaming stick or television does. In order to get pseudo-HDR playback on these devices I have generated three Gamma 2.4 Rec. 709 limited HDR versions of the content that the video player will detect and serve to Android TV and Amazon Fire TV televisions and streaming dongles.
If your display has user selectable Gamma, set this value to 2.4. If your dongle or set top box has an option to set it to operate in HDR, do that (varies by device). Set your display brightness to max. Then, download and install the Puffin browser (Android TV) or Silk Browser (Amazon Fire TV), log in, and open the video page. Pseudo-HDR should automatically be detected and activated (see Overriding HDR Auto-detection below).
My workaround to render HDR video correctly only works in the Puffin and Silk browsers, since I'm using these browser IDs to serve up the correct content. Six pseudo-HDR streams are available at three peak brightness levels, and two quality levels each. To change video streaming settings, select the video icon in the bottom-right corner of the video player, and select your peak SDR display brightness (400, 600, or 1000 nits) and video quality (lq or hq). Lowest quality streams in 720p @ 2.5-3 Mbps, High quality streams in 1080p @ 5.5 - 6 Mbps. Default is 400 nits peak hq @ 5.5 - 6Mbps.
On WebVideoCaster (Roku, AppleTV, AndroidTV, Samsung Tizen, VIEWD TV & Blu-ray Players, DLNA TVs)
The receiver application WebVideoCaster is available to install on Roku, AppleTV, AndroidTV, Samsung Tizen TVs, and TVs & Blu-ray players using the VIEWD app store (including Sony TVs), and the controller application is available as a download for iOS and Android. Unlike AirPlay or Chromecast specifications that decode video at the host and recompress it to send to the device, the WebVideoCaster controller pulls the stream from the website and then forwards the original video stream to the television or set top box, allowing the receiving TV / device to handle the HDR decoding and playback, without sacrificing video quality. This is the recommended solution for HDR playback on Roku, AppleTV, AndroidTV, Samsung Tizen Televisions, and VIEWD enabled televisions & devices.
On the receiving device, using your device's app store, search for and install the WebVideoCaster app. On your controller device's app store, search for and install the WebVideoCaster app. The free, ad-supported version of the app will work in HDR without paying for premium. With the app open on your television or set top box, open the WebVideoCaster app on your controller and select the casting icon in the top right corner. Select your television or device and follow the prompts to link the apps (if necessary).
Then, on the controller app, log in and open the video page. If the device you're using to control playback has HDR support, HDR will be automatically detected. If not, you will need to override the auto-detection (see Overriding HDR Auto-detection below). Playback should begin on the television or set top box, and the controller app will offer playback controls.
The first time you connect you may experience some difficulties linking the television or set top box/streaming stick to the app. Try different casting settings to see what works best for your devices.
The WebVideoCaster platform supports casting to AirPlay, Chromecast, and DLNA devices. I recommend avoiding using AirPlay or Chromecast methods, since these will reencode the streamed video into 8-bits for transmission.
See WebVideoCaster's website for more information on the app and supported devices.