Patent ID: 6072835
Filing Date: 2000-06-06
Classification: H04N

Abstract:
A variable transfer rate coding method of coding moving picture signals of a plurality of groups of pictures, comprising the steps of:quantizing the moving picture signals under control of quantization step width per group of pictures;coding the quantized picture signals per group of pictures, the coding being executed by a first coding and a second coding executed after the first coding;obtaining a first code amount of the coded picture signals per group of pictures coded by the first coding and a second code amount of the coded picture signals per picture or block-unit obtained by dividing the picture included in each group of pictures coded by the first coding;calculating, in response to the first code amount, a temporal total code amount of the moving picture signals of the plurality of groups of pictures by processing the first code amount with conversion characteristics;comparing the temporal total code amount with a reference total code amount, to decide a first target code amount for the second coding per group of pictures in order that a total code amount obtained by calculating the first target code amount becomes a maximum amount within the reference total code amount;determining, in response to the first target code amount and the second code amount, a second target code amount for the second coding per the picture or the block-unit included in each group of pictures in accordance with the maximum amount of the total code amount; andvarying the quantization step width on the basis of the second target code amount for the second coding by the coding step.