Concept for varying a coding quantization parameter across a picture, coding quantization parameter adjustment, and coding quantization parameter adaptation of a multi-channel picture

Abstract

Coding quantization parameter variation or adaptation is made more effective by basing the determination of a coding quantization parameter for a predetermined block of the picture on a dispersion of a statistical sample value distribution of a high-pass filtered version of the predetermined block. The usage of the high-pass filtered version of the predetermined block as a basis for the determination of the dispersion instead of using, for instance, the un-filtered or original version of the predetermined block assists in a better adaptation of the resulting coding quantization parameter variation across the picture to the human visual system. Alternatively or additionally, coding quantization parameter variation or adaptation across a picture is made more efficient by a control of coding quantization parameter variation/adaptation across a picture in a manner dependent on a prediction of the actual dispersion. In order to improve the coding efficiency in encoding a picture into a data stream, a comparison between a first coding quantization parameter assigned to a predetermined block of the picture and a threshold which depends on a mean difference of sample values of the predetermined block to sample values' mean value may be performed.