Method for carrying out integer approximation of transform coefficients, and coder and decoder

摘要

A limited value range is defined for obtaining approximated integer cosine transform coefficients. The transform coefficients of the base vectors for the submatrices are selected by taking into account the orthogonality condition so that the sum of their squares yields the square of the constant component coefficient. The coefficients of the variable components are derived from these coefficients. These measures yield the advantage that in quantization and normalization, a uniform normalization and quantization factor may be used for all coefficients.