I-Frame

Short for intraframe, a video compression method used by the MPEG standard. In a motion sequence, individual frames of pictures are grouped together (called a group of pictures, or GOP) and played back so that the viewer registers the video s spatial motion. Also called a keyframe, an I-frame is a single frame of digital content that the compressor examines independent of the frames that precede and follow it and stores all of the data needed to display that frame. Typically, a I-frames are interspersed with P-frames and B-frames in a compressed video. The more I-frames that are contained, the better quality the video will be; however, I-frames contain the most amount of bits and therefore take up more space on the storage medium.

Also see P-frame and B-frame.