Block-based parallel deblocking filter in video coding

A system comprising one or more processors configured to:

• compute a first measure of deviation at a first four-sample boundary segment based on samples in a first sub-block of a filtering block, wherein the filtering block includes portions of four sample blocks, wherein the four sample blocks include a first sample block, and wherein the filtering block is offset from the first sample block of the four sample blocks by four samples;
• use the first measure of deviation in deblocking filter decisions for the first four-sample boundary segment;
• compute a second measure of deviation at a second four-sample boundary segment based on samples in a second sub-block of the filtering block;
• and
• use the second measure of deviation in deblocking filter decisions for the second four-sample boundary segment;
• wherein to use the first measure of deviation in deblocking filter decisions, the one or more processors are configured to:
• make a filter on/off decision jointly for all rows of the first filtering sub-block using the first measure of deviation when the first filtering sub-block is a top 8×4 filtering sub-block;
• and
• make a filter on/off decision jointly for all columns of the first filtering sub-block based on the first measure of deviation when the first filtering sub-block is a left 4×8 filtering sub-block.

A non-transitory computer readable medium comprising instructions that when executed in a digital system, cause the digital system to:

• compute a first measure of deviation at a first four-sample boundary segment based on samples in a first sub-block of a filtering block, wherein the filtering block includes portions of four sample blocks, wherein the four sample blocks include a first sample block, and wherein the filtering block is offset from the first sample block of the four sample blocks by four samples;
• use the first measure of deviation in deblocking filter decisions for the first four-sample boundary segment;
• compute a second measure of deviation at a second four-sample boundary segment based on samples in a second sub-block of the filtering block;
• and
• use the second measure of deviation in deblocking filter decisions for the second four-sample boundary segment;
• wherein the instructions to use the first measure of deviation in deblocking filter decisions comprises:
• instructions to make a filter on/off decision jointly for all rows of the first filtering sub-block using the first measure of deviation when the first filtering sub-block is a top 8×4 filtering sub-block;
• and
• instructions to make a filter on/off decision jointly for all columns of the first filtering sub-block based on the first measure of deviation when the first filtering sub-block is a left 4×8 filtering sub-block.