i almost forgot about these concepts...long time haven't touched them..
but i think you can search for
"information theory" books in this edaboard to find the answer.
Added after 3 minutes:
some info on wiki:
h**p://en.wikipedia.org/wiki/Source_coding
h**p://en.wikipedia.org/wiki/Channel_coding
--> In digital telecommunications, channel coding is a
pre-transmission mapping applied to a digital signal or data file,
usually with an error-detection or an error-correction code.