Video signals can require enormous capacity (How Large are Video Data Files?) for transport and storage. For these reasons, it is often desired to "compress" the signals to reduce the signal's size. With a well designed computer program, the compression can be achieved with little distortion.
The satellite TV companies, "The Dish Network", and "DirecTV", were pioneers in the use of signal compression. These companies have used a standard called MPEG-2 (MPEG is short for the "Motion Pictures Expert Group").
Compression has also been applied to audio signals. For example "MP3" is actually an abbreviation for "MPEG Audio layer 3", which is part of an Audio/Video compression program.
MPEG-4 is one of the newer compression methods, designed specifically for efficient video signal compression. MPEG-4 was originally developed for transporting video signals over the Internet, but has found wide success with HDTV signals as well. DivX is an example of an MPEG-4 encoder.
Sony was the first company to commercially introduce H.264 (MPEG-4 Part 10), a more advanced revision of the MPEG-4. Blue-Ray DVDs, for example, use the H.264 standard for storage. This standard has also gained rapid acceptance in the security camera industry. H.264 is 2-3 times more efficient than the MPEG-2 standard.
No comments:
Post a Comment