Method of bit stream processing

摘要

The invention concerns a method of bit stream watermarking in a tandem coding system ( 300 ). The method involves arranging for the system ( 300 ) to comprise a series of stages including a first quantizing unit for processing an input signal to generate a first intermediate signal, a combining unit for embedding a watermarking signal into the intermediate signal to generate a second intermediate signal, and a second quantizing unit for processing the second intermediate signal to generate a watermarked output signal. The first quantizing unit to arranged to include a unit for predicting distortions arising in subsequent stages of the system ( 300 ) and generating one or more corresponding quantization noise reduction parameters. Moreover, the system ( 300 ) is operable to apply the one or more reduction parameters in at least one of the subsequent stages for reducing noise and/or distortion arising within the system ( 300 ).