The highest video resolution supported by the Nikon D3100 is 1920 x 1080 pixels. That's over six times the video resolution of the most frequently found video resolutions of 640 x 480 pixels. In addition, this digital camera support a video resolutions of 640 x 424 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.
This digital camera's video resolution (1920 x 1080 pixels) is actually the best supported video resolution amongst all medium megapixel cameras that have been around for more than two years.
A 320 x 120 pixels video resolutions is the worst supported video resolution across comparable types of digital camera.
What does "video resolutions" mean?