This lesson will cover the video formats supported by H.261. We’ll then get into frame sequencing and Intra-frame (I-frame) and Inter-frame (P-frame) coding which describe how frames in a video are compressed and encoded to reduce the file size and maximize perceived quality by the user. Then we’ll cover Predictive Coding, where a motion vector estimates the amount of changing pixels in successive macroblocks which make up a video frame. We will also cover quantization in H.261, which averages out small differences in adjacent and successive blocks arranged together in Group of Block (GOB) Structures. Then we’ll provide some insight into what bitrate is in video.