Picture coding method and picture decoding method
The method includes the following units: a coefficient number detecting unit ( 109 ) for detecting the number of coefficients which has a value other than 0 for each block according to the generated coefficient, a coefficient number storing unit ( 110 ) for storing the number of coefficients detected, a coefficient number coding unit ( 111 ) for selecting a table for variable length coding based on the numbers of coefficients in the coded blocks located on the periphery of a current block to be coded with reference to the selected table for variable length coding so as to perform variable length coding for the number of coefficients.
1. A receiving apparatus which receives multiplexed data which is obtained by multiplexing coded audio data and coded picture data, said receiving apparatus comprising:
a demultiplexing unit configured to separate the multiplexed data into the coded audio data and the coded picture data;
an audio processing unit configured to decode the separated coded audio data; and
a picture decoding unit configured to decode the separated coded picture data,
wherein said picture decoding unit includes a block decoding unit configured to decode coded block data included in the coded picture data, the coded block data being obtained by dividing a picture signal into plural blocks, generating a residual block image from a block image of the respective blocks and a predictive block image obtained by intra-picture prediction or inter-picture prediction, and coding, on a block basis, coefficients obtained by performing orthogonal transformation and quantization on the residual block image,
said block decoding unit includes:
a coefficient number decoding unit configured to decode the coded block data to obtain the number of non-zero coefficients which are coefficients included in a current block to be decoded and having a value other than “0”;
a unit configured to obtain coefficients corresponding to a residual block image of the current block by decoding the coded block data;
a unit configured to obtain the residual block image of the current block by performing inverse quantization and inverse orthogonal transformation on the coefficients corresponding to the residual block image of the current block; and
a reproducing unit configured to reproduce a block image of the current block, from the obtained residual block image and a predictive block image obtained by intra-picture prediction or inter-picture prediction,
said coefficient number decoding unit includes:
a determining unit configured to determine a predictive value for the number of non-zero coefficients included in the current block based on the number of non-zero coefficients included in a decoded block located on a periphery of the current block;
a selecting unit configured to select a variable length code table based on the determined predictive value; and
a variable length decoding unit configured to perform variable length decoding on a coded stream which is generated by coding the number of the non-zero coefficients included in the current block, by using the selected variable length code table.