Byte Pair Encoding - Byte Pair Encoding Example

Byte Pair Encoding Example

Suppose we wanted to encode the data

aaabdaaabac

The byte pair "aa" occurs most often, so it will be replaced by a byte that is not used in the data, "Z". Now we have the following data and replacement table:

ZabdZabac Z=aa

Then we repeat the process with byte pair "ab", replacing it with Y:

ZYdZYac Y=ab Z=aa

We could stop here, as the only literal byte pair left occurs only once. Or we could continue the process and use recursive byte pair encoding, replacing "ZY" with "X":

XdXac X=ZY Y=ab Z=aa

This data cannot be compressed further by byte pair encoding because there are no pairs of bytes that occur more than once.

To decompress the data, simply perform the replacements in the reverse order.