The highest video resolution supported by the Coolpix P310 is 1920 x 1080 pixels. That's over six times the video resolution of a 640 x 480 pixels camera, which is the most frequently found video resolution supported by similar spec digital cameras that have been around for around the same time as the Coolpix P310. 640 x 480 pixels is also supported by this Nikon camera. In addition, this camera support a video resolution of 960 x 540 pixels and 1280 x 720 pixels. A video resolution of 1920 x 1080 pixels is equivalent to Full HD video. You will require a Full HD TV or better to appreciate this level of detail.
A 1920 x 1080 pixels video resolution is in fact the best supported video resolution amongst all similar spec cameras that have been on the market for a comparable time to the Coolpix P310.
A 320 x 240 pixels video resolution is the worst supported video resolution across comparable types of digital camera.