说明：  A few short years ago, the applications for video were somewhat confined—analog was used for broadcast and cable television, VCRs, set-top boxes, televisions and camcorders. Since then, there has been a tremendous and rapid conversion to digital video, mostly based on the MPEG-2 video compression standard. Today, in addition to the legacy DV, MPEG-1 and MPEG-2 audio and video com- pression standards, there are three new high- performance video compression standards. These new video codecs offer much higher video compression for a given level of video quality.
(A few short years ago, the applications forvideo were somewhat confined-analog wasused for broadcast and cable television, VCRs, set-top boxes, televisions and camcorders.Since then, there has been a tremendous andrapid conversion to digital video, mostly basedon the MPEG-2 video compression standard.Today, in addition to the legacy DV, MPEG-1 and MPEG-2 audio and video com-pression standards, there are three new high-performance video compression standards.These new video codecs offer much highervideo compression for a given level of videoquality.)