This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
Alright. First, we have to separate between decoder and
encoder.
Remember: the MPEG coding is done asymmetrical, with a much
larger workload on the encoder than on the decoder.
For a stereo decoder, variuos real-time implementations exist
for Layer-2 and Layer-3. They are either based on single-DSP
solutions or on dedicated MPEG audio decoder chips. So
you need not worry about decoder complexity.
For a stereo Layer-2-encoder, various DSP based solutions with
one or more DSPs exist (with different quality, also).
For a stereo Layer-3-encoder achieving ISO reference quality,
the current real-time implementations use two DSP32C and
two DSP56002.
 
Continue to: