The current best method of storing music is digitally. The main problem with this format is the amount of information which is required to retain CD-quality sound. For a 5 minute song, approximately 50 megabytes of storage space is required. One possible way to overcome this problem is to compress the audio signal. An international standard algorithm for audio compression called MPEG, removes the parts of the signal which the human ear cannot detect. The parts of the sound that humans cannot hear can be thrown away and the remaining binary signal can be compressed with conventional lossless compression. Using this method, the 50 MB space can be reduced to approximately 5 MB. However, to implement the decoding algorithm in real-time one needs to perform about 12 million instructions per second. Using today's computers this will take up the entire power of the computer and render it useless while decoding. Our project is to design a module that will decode a MPEG compressed bitstream in real-time, while keeping the computers CPU use to a minimum.

This document is the final report for the MPEG decoder module design project by Kire Filipovski and Mike Schwankl. The decoder module is a stand-alone device capable of decompressing a MPEG layer 2 encoded audio bitstream. The decoder implements a dedicated DSP chip and externally interfaces with a computer via its parallel port and provide an analog output rivaling a CD-quality signal. This product is suitable for any applications with bandwidth or digital storage restrictions such as high-quality audio over telephone lines or data networks, music archives etc.