Download the free tool MediaInfo . Open the file in question. Look at the line. It must say HEVC . Look at the "Width" – it must be 3840 pixels. Look at the "Bit rate" – it should exceed 15.0 Mb/s (15,000 kb/s) for streaming quality, or 45.0 Mb/s for disc quality.

In the context of Japanese adult media, "4K Verified" usually refers to: