Digital Video and DSP: Instant Access

Technology Trade-offs

Since video is just a series of still images, and baseline JPEG encoders and decoders were readily available, people used baseline JPEG to compress real-time video (also called motion JPEG or MJPEG). However, this technique does not take advantage of the frame-to-frame redundancies to improve compression, as does MPEG. JPEG is symmetrical, meaning the cost of encoding and decoding is roughly the same. MPEG, on the other hand, was designed primarily for mastering a video once and playing it back many times on many platforms. To minimize the cost of MPEG hardware decoders, MPEG was designed to be asymmetrical, with the encoding process requiring about 100×the computing power of the decoding process.

Since MPEG is targeted ...