MPEG is a standard for compressing moving pictures. It uses the similarity between frames to create a sequence of I, B and P frames. Only the I frame contains all the picture data. The B and P frames only contain information relating to changes since the last I frame. MPEG-1 uses a data rate of 1.2 Mbps, the speed of CD-ROM. MPEG-2 support much higher quality with a data rate (also called bit rate) of from 1.2 to 15 Mbps. MPEG-2 is the format most favored for video on demand, DVD, and is the format for transmitting digital television.