In July of 2010, YouTube service announced the support of 4K video with the resolution of 4096 x 3072. Presently, several dozens of videos with 4K resolution are presented on YouTube.
Official examples of videos are available in the playlist named 4k Resolution. It is also possible to search by phrases "4k Resolution", "4k" or "4096p". Regarding the terminology, the last request is not fully correct, because indications 480p, 720p, 1080p reffer to the vertical resolution, but, nevertheless, some part of 4K videos is presented with this tag. Even some 4K cartoons are available on YouTube.
In the middle of the 2000s, 4K digital cameras appeared on markets. The first available device for sale was Dalsa Origin camera of Canadian Dalsa Corporation Company. It could make the video with the resolution of 4096 x 2048 in 16 bit RAW-format. This format conveys a very high dynamic range. Before, digital cameras’ color format was within 8, 10 or 12 bit. Dalsa Origin camera records video on an off-site storage with the speed of 400 MByte/sec.
In 2007, Red Digital Cinema Camera Company released a Red One camera. The camera had 12 megapixel CMOS-sensor and made the video with the resolution of 4096 x 2304, and the speed was 30 fps. In the beginning of 2011, the company presented a Red Epic camera with the 14 megapixel sensor and resolution of 5120 x 2700.
Many up-to-date DSLR-cameras, even not professional ones, make the video with the resolution of 1920 x 1080, having the sensor with the resolution of over 12 megapixels. For instance, Nikon D3100 camera makes photos with the resolution of 4608 x 3072, and a sensor of Canon EOS 550D camera has the resolution of 5184 x 3456.
Thanks to the methods, described on specialized forums, it is possible to create a video made by a fast shooting on similar cameras. One can find examples of such a video on YouTube. It is possible to watch a video via links with the resolution of 4000 x 2662 made by Nikon D3s camera in 3 fps shooting mode: 4000 x 2662, Nikon D3s, burst shutter.