A way or representing and compressing 8x8 pixel blocks of an image in terms of amplitude and color. A technique for representing waveform data as a weighted sum of cosines. This usage of DCT results in lossy compression. The basic idea behind MPEG video compression is to remove spatial redundancy within a video frame and temporal redundancy between video frames. As in JPEG, the standard for still image compression, DCT-based compression is used to reduce spatial redundancy.
Motion- compensation is used to exploit temporal redundancy.
The images in a video stream usually do not change much within small time intervals. The idea of motion-compensation is to encode a video frame based on other video frames temporally close to it. Acronym for Decoding Time Stamp. The video and audio portions of the specification describe the basic format of the video or audio stream. These formats define the Elementary Streams.