Method for encoding and decoding image using adaptive deblocking filtering, and apparatus therefor

An image encoding method performing adaptive filtering, the method comprising:

• determining whether a reference block for prediction exists in the current picture where a current block is positioned;
• generating a prediction block for the current block by using the reference block;
• reconstructing the current block by using the prediction block;
• and
• adaptively applying a deblocking filter on a first pixel of the reconstructed current block and a second pixel of a neighboring block adjacent to the reconstructed current block based on a filter strength,
• wherein, the filter strength of the deblocking filter is determined depending on whether the current block or the neighboring block is predicted with intra prediction,
• wherein, based on the current block and the neighboring block is not predicted with intra prediction, the filter strength of the deblocking filter is determined depending on whether a block boundary between the first pixel and the second pixel is a block boundary of a transform block and whether a block containing the first pixel or a block containing the second pixel has a non-zero coefficient,
• wherein, based on the block containing the first pixel and the block containing the second pixel not having the non-zero coefficient, the filter strength of the deblocking filter is determined depending on a color component of the current block, whether a block containing the first pixel is predicted with a reference block within the current picture, and whether a block containing the second pixel is predicted with a reference block within the current picture,
• wherein the filter strength of the deblocking filter is determined to be 1 when the block containing the first pixel is predicted with a reference block within the current picture and the block containing the second pixel is predicted with the reference block within the current picture, and
• wherein, among a luma component and a chroma component of the current block, the filter strength for any one component of the current block is determined separately without considering a filter strength for the other one component of the current block.

A method of transmitting a bitstream generated by an image encoding method performing adaptive filtering, the image encoding method comprising:

• determining whether a reference block for prediction exists in the current picture where a current block is positioned;
• generating a prediction block for the current block by using the reference block;
• reconstructing the current block by using the prediction block;
• and
• adaptively applying a deblocking filter on a first pixel of the reconstructed current block and a second pixel of a neighboring block adjacent to the reconstructed current block based on a filter strength,
• wherein, the filter strength of the deblocking filter is determined depending on whether the current block or the neighboring block is predicted with intra prediction,
• wherein, based on the current block and the neighboring block is not predicted with intra prediction, the filter strength of the deblocking filter is determined depending on whether a block boundary between the first pixel and the second pixel is a block boundary of a transform block and whether a block containing the first pixel or a block containing the second pixel has a non-zero coefficient,
• wherein, based on the block containing the first pixel and the block containing the second pixel not having the non-zero coefficient, the filter strength of the deblocking filter is determined depending on a color component of the current block, whether a block containing the first pixel is predicted with a reference block within the current picture, and whether a block containing the second pixel is predicted with a reference block within the current picture,
• wherein the filter strength of the deblocking filter is determined to be 1 when the block containing the first pixel is predicted with a reference block within the current picture and the block containing the second pixel is predicted with the reference block within the current picture, and
• wherein, among a luma component and a chroma component of the current block, the filter strength for any one component of the current block is determined separately without considering a filter strength for the other one component of the current block.