The process of converting, or digitizing, the almost infinitely variable
amplitude of an
analog waveform to one of a finite series of discrete levels. In
video compression, quantization is a process that attempts to determine what information
can be discarded safely without a significant loss in visual fidelity. The
quantization process is inherently
lossy because of the many-to-one mapping
process.
[Source: Xilinx Web site]