Video encoding apparatus, video encoding method, video decoding apparatus, and video decoding method

A video encoding method that encodes a block to be encoded among a plurality of blocks obtained by dividing a picture to be encoded, included in video data, the method comprising:

• performing orthogonal transformation on prediction error signals of respective pixels in the block to be encoded, to calculate orthogonal transform coefficients, and quantizing the orthogonal transform coefficients based on a quantization value applied to the block to be encoded, to encode the block to be encoded;
• decoding the encoded block to be encoded, to generate a locally-decoded block;
• correcting filter coefficients of an in-loop filter applied to an encoded reference block adjacent to the block to be encoded, based on a quantization value applied to the reference block and the quantization value applied to the block to be encoded, to calculate corrected filter coefficients, when a mode of an in-loop filter applied to the block to be encoded is same as a mode of the in-loop filter applied to the reference block;
• using the corrected filter coefficients to apply the in-loop filter to the locally-decoded block;
• and
• adding, to encoded data of the block to be encoded, information indicating that the block to be encoded refers to the reference block for the in-loop filter.

A video decoding apparatus that decodes a block to be decoded among a plurality of blocks obtained by dividing a picture to be decoded, included in encoded video data, the video decoding apparatus comprising:

• a processor configured to:
• inversely quantize quantization coefficients included in encoded data of the block to be decoded, based on a quantization value applied to the block to be decoded, to calculate orthogonal transform coefficients;
• perform inverse orthogonal transformation on the orthogonal transform coefficients to calculate prediction error signals of respective pixels in the block to be decoded;
• decode the block to be decoded, based on the prediction error signals of the respective pixels;
• correct filter coefficients of an in-loop filter applied to a decoded reference block adjacent to the block to be decoded, included in the encoded video data, based on a quantization value applied to the reference block and the quantization value applied to the block to be decoded, to calculate corrected filter coefficients, when information indicating that the reference block is referred to for an in-loop filter is included in the encoded data of the block to be decoded;
• and
• use the corrected filter coefficients to apply the in-loop filter to the decoded block to be decoded.

A video decoding method that decodes a block to be decoded among a plurality of blocks obtained by dividing a picture to be decoded, included in encoded video data, the method comprising:

• inversely quantizing quantization coefficients included in encoded data of the block to be decoded, based on a quantization value applied to the block to be decoded, to calculate orthogonal transform coefficients;
• performing inverse orthogonal transformation on the orthogonal transform coefficients to calculate prediction error signals of respective pixels in the block to be decoded;
• decoding the block to be decoded, based on the prediction error signals of the respective pixels;
• correcting filter coefficients of an in-loop filter applied to a decoded reference block adjacent to the block to be decoded, included in the encoded video data, based on a quantization value applied to the reference block and the quantization value applied to the block to be decoded, to calculate corrected filter coefficients, when information indicating that the reference block is referred to for an in-loop filter is included in the encoded data of the block to be decoded;
• and
• using the corrected filter coefficients to apply the in-loop filter to the decoded block to be decoded.