Adaptive Loop Filtering with Critical Frame Coefficient Reuse

The patent applies preliminary action by pre-deriving filter coefficients for critical frames (such as I-frames and P-frames) before they are needed for actual filtering operations. This allows the complex coefficient derivation to be performed in advance during encoding, rather than in real-time during decoding, thus improving filtering accuracy while reducing runtime computational complexity and hardware implementation difficulty.

The patent applies local quality by selectively deriving filter coefficients only for critical frames (I-frames and P-frames) rather than every frame. This approach maintains high video quality by ensuring that frames requiring accurate filtering have properly derived coefficients, while reducing encoding time and latency by avoiding redundant coefficient derivation for frames where it is not necessary.

The patent applies partial action by selectively enabling chroma and cross-component adaptive loop filters only for critical frames where they provide the most benefit. This maintains color accuracy for important frames while reducing overall computational demands by avoiding unnecessary filter applications on frames where full chroma filtering is not required.