How many pixels in HD?

There are several different formats of HD. The one used most widely is 1080 x 1920. Multiply the number of lines by the number of pixels per line and you get 2073600 pixels per frame. Each pixel requires 3 bytes to display 24 bit colour so there are 6220800 bytes per frame. (broadcast equipment uses more bits per pixel). Note that the number of pixels is per frame, so a 1080i (interlaced) image will have the same number of pixels but will use two separate fields to display them. Finally, as there are 29.97 frames per second (US standard) a full HD image will need around 186 megabytes per second for full quality moving video.