Crunchyroll does not natively stream in 4K for most content. Instead, they use a real-time AI upscaling algorithm called Anime4K within the browser/client-side.
or devices for using the WebGLShader AI upscaler? How To Increase Quality on Crunchyroll 4k_crunchyroll.txt
To ensure the best experience, users can adjust settings to "Highest" within the video player. Crunchyroll does not natively stream in 4K for most content
Access to the library, including higher quality upscaled content, requires a subscription. Viewing and Quality Management including higher quality upscaled content
The platform utilizes the WebGLShader API to take 1080P content and upscale it to 4K resolutions, allowing users with 4K monitors or TVs to view higher-fidelity content.