The Canon EOS 1D X Mark II supports a maximum video resolution of 4096 x 2160 pixels. That's 7% more video resolution than a 3840 x 2160 pixels digital camera, which is the most common video resolution supported by digital cameras that have been available for the last year. This camera also supports a video resolutions of 1920 x 1080 pixels.
This digital camera's video resolution (4096 x 2160 pixels) is actually the best supported video resolution across all comparable spec cameras that came out around the same time as the EOS 1D X Mark II.
The worst supported video resolution amongst comparable types of digital camera is 320 x 240 pixels.