Film EOPA Practice Test

Vertical resolution is what 480 lines describes. In standard-definition video, resolution was historically described by how many horizontal scan lines run from top to bottom of the image. Saying there are 480 lines means the image is built from 480 horizontal lines stacked vertically, so it tells you how tall the picture is in terms of detail. It doesn’t specify how many pixels wide the image is—that depends on the format and sampling used for the width. It also isn’t about how many frames per second are shown (frame rate) or the width-to-height proportion (aspect ratio). So, 480 resolution lines pin down vertical resolution in SD contexts. For context, NTSC SD typically uses 480 visible lines (out of 525 total), while PAL SD uses about 576 visible lines (out of 625 total).