MP3 decoder chips

I am looking for a simple audio MP3 encoder - transmission line -
decoder system.

What are the latest encoder and decoder chips used for this?

I have seen some of the websites such as "mp3projects" and others, but
I am not sure if there are newer (cheaper) versions of the chips for
encoding and decoding

Also, any web pointers to a good description on how it all works (a
techie oriented version preferably)

Any suggestions?

Thanks

Ted

 

Why?
There may be many ways to do this.
The key point is probably what's the transmission line.