Moving-picture encoding apparatus and moving-picture decoding apparatus

摘要

According to one embodiment, an encoding apparatus includes a prediction unit, a classifying unit, a first transformer, a second transformer, an order controller, and an entropy coder. The prediction unit obtains a predictive residual signal to be encoded, by using a mode selected from intra-prediction modes. The first transformer obtains first transformation coefficients by subjecting the signal to an orthogonal transformation by use of a first transformation basis if the selected mode is classified into a mode having a prediction direction. The first transformation basis is preset so that a coefficient density after the orthogonal transformation is higher than a coefficient density.

主权项

1. A moving-picture decoding system, comprising:
circuitry configured to:
obtain transformation coefficients from coded data obtained by coding processes according to prediction directions;rearrange the transformation coefficients according to a scanning order corresponding to a prediction direction of a target block from among scanning orders predetermined for prediction directions;classify a mode applied to the target block into a predetermined first mode or a predetermined second mode;obtain a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; andgenerate a decoded image signal by use of the predictive residual signal, wherein the first transformation basis is used for both of a vertical inverse orthogonal transformation and a horizontal inverse orthogonal transformation, and the second transformation basis is used for both of the vertical inverse orthogonal transformation and the horizontal inverse orthogonal transformation.