Define Compression

Compression

Compression is the process of coding that will effectively reduce the total number of bits needed to represent certain information.

Input  data -> Encoder compression -> Storage or network -> Decoder decompression -> Output data

If the compression reduce no information loss, then the scheme is lossless compression, otherwise it is lossy.

Compression ratio is the ratio of number of bits before compression and number of bits after compression.

So,

Compression ratio = (Number of bits before compression) / (Number of bits after compression)

=B0/B1

where, Bo = Number of bits before compression and

B1 = Number of bits after compression.