From MATLAB help:
arithenco Encode a sequence of symbols using arithmetic coding. CODE = arithenco(SEQ, COUNTS) generates binary arithmetic code corresponding to the sequence of symbols specified in the vector SEQ. The vector COUNTS contains the symbol counts (the number of times each symbol of the source's alphabet occurs in a test data set) and represents the source's statistics.
Example:
% Consider a source whose alphabet is {x, y, z}. A 177-symbol test data
% set from the source contains 29 x's, 48 y's and 100 z's. To encode the
% sequence yzxzz, use these commands:
seq = [2 3 1 3 3];
counts = [29 48 100];
code = arithenco(seq, counts)
