Quantization circuitry as for video signal compression systems

摘要

In a compression system including a quantizer (14) for quantifying a matrix of coefficients according to a matrix of quantizing values, and which is responsive to rate buffer (24) occupancy for providing quantizing scale factors (26) to modify the quantizing matrix, significant channel capacity may be salvaged without significant loss of image quality by incorporating apparatus to limit (28) the minimum values of quantizing scale factors that are applied to the quantizing matrix.