Screen Content Coding Loop Filter Disabling

The patent applies different filtering treatments to different blocks based on their prediction mode. Specifically, blocks coded with screen content coding tools (palette mode, IBC mode, BDPCM mode, or transform skip mode) have their loop filters selectively disabled, while other blocks receive normal filtering. This local differentiation ensures that filtering quality is maintained where needed while avoiding unnecessary processing in screen content blocks, thereby resolving the contradiction between filtering quality and coding efficiency.

The patent selectively disables deblocking filters for blocks coded with screen content coding tools while maintaining them for other blocks. Since screen content blocks typically have sharp edges and text-like structures where filtering can introduce artifacts and increase complexity, this local approach avoids the harmful effects of filtering in appropriate regions while preserving boundary artifact reduction where it is beneficial, thus improving compression ratio without sacrificing necessary filtering quality.

The patent implements conditional loop filter disabling based on prediction mode. Blocks coded with screen content coding tools (palette mode, IBC mode, BDPCM mode, or transform skip mode) have loop filters disabled, while blocks using other prediction modes receive normal loop filtering. This selective approach maintains reconstructed signal quality for blocks that benefit from filtering while avoiding unnecessary computational overhead for screen content blocks, effectively resolving the contradiction between signal quality and computational resource usage.