Apparatus and method for performing deblocking

A method for deblocking a block edge between a first image block and a second image block by a coding device, the method comprising:

• determining a value of MA′ to be 5 under one condition that N being an even integer 2n larger than 16 when the first image block includes sub-blocks, wherein n is a positive integer, wherein the first image block has a block size of M*N, and M and N represent a width and a height of the first image block respectively;
• determining a value of MB′ to be 5 under one condition that T being an even integer 2n larger than 16 when the second image block includes sub-blocks, wherein the second image block has a block size of L*T, and L and T represent a width and a height of the second image block respectively;
• modifying values of at most MA′ samples of the first image block as third output values, wherein the at most MA′ samples are in a line perpendicular to the block edge and the at most MA′ samples are adjacent to the block edge;
• and
• modifying values of at most MB′ samples of the second image block as fourth output values, wherein the at most MB′ samples are in a line perpendicular to the block edge and the at most MB′ samples are adjacent to the block edge.

A deblocking filter apparatus for deblocking a block edge between a first image block and a second image block, comprising:

• a memory storing instructions;
• and
• a processor in communication with the memory and upon execution of the instructions, is configured to:
• determine a maximum filter length MA′ to be 5 under one condition that N being an even integer 2n larger than 16 when the first image block includes sub-blocks, wherein n is a positive integer, wherein the first image block has a block size of M*N, and M and N represent a width and a height of the first image block respectively;
• determine a maximum filter length MB′ to be 5 under one condition that T being an even integer 2n larger than 16 when the second image block includes sub-blocks, wherein the second image block has a block size of L*T, and L and T represent a width and a height of the second image block respectively;
• modify, based on the maximum filter length MA′, values of samples of the first image block, wherein the samples of the first image block are in a line perpendicular to the block edge and the samples of the first image block are adjacent to the block edge;
• and
• modify, based on the maximum filter length MB′, values of samples of the second image block, wherein the samples of the second image block are in a line perpendicular to the block edge and the samples of the second image block are adjacent to the block edge.

A deblocking method for deblocking a block edge between a first image block and a second image block by a coding device comprising:

• determining a maximum filter length MA′ to be 5 under one condition that N being an even integer 2n larger than 16 when the first image block includes sub-blocks, wherein n is a positive integer, wherein the first image block has a block size of M*N, and M and N represent a width and a height of the first image block respectively;
• determining a maximum filter length MB′ to be 5 under one condition that T being an even integer 2n larger than 16 when the second image block includes sub-blocks, wherein the second image block has a block size of L*T, and L and T represent a width and a height of the second image block respectively;
• modifying, based on the maximum filter length MA′, values of samples of the first image block, wherein the samples of the first image block are in a line perpendicular to the block edge and the samples of the first image block are adjacent to the block edge;
• and
• modifying, based on the maximum filter length MB′, values of samples of the second image block, wherein the samples of the second image block are in a line perpendicular to the block edge and the samples of the second image block are adjacent to the block edge.

A non-transitory computer-readable medium storing computer instructions that, when executed by one or more processors, cause the one or more processors to perform operations for deblocking a block edge between a first image block and a second image block in image encoding or image decoding, the operations comprising:

• determining a maximum filter length MA′ to be 5 under one condition that N being an even integer 2n larger than 16 when the first image block includes sub-blocks, wherein n is a positive integer, wherein the first image block has a block size of M*N, and M and N represent a width and a height of the first image block respectively;
• determining a maximum filter length MB′ to be 5 under one condition that T being an even integer 2n larger than 16 when the second image block includes sub-blocks, wherein the second image block has a block size of L*T, and wherein L and T represent a width and a height of the second image block respectively;
• modifying, based on the maximum filter length MA′, values of samples of the first image block, wherein the samples of the first image block are in a line perpendicular to the block edge and the samples of the first image block are adjacent to the block edge;
• and
• modifying, based on the maximum filter length MB′, values of samples of the second image block, wherein the samples of the second image block are in a line perpendicular to the block edge and the samples of the second image block are adjacent to the block edge.