HEVC Video Coding Acceleration via Gradient Complexity and Adaboost

The video sequence is divided into multiple picture blocks that are processed independently. Each picture block undergoes separate gradient calculation, complexity assessment, and mode determination, enabling parallel processing and reducing overall coding time while maintaining compression efficiency.

Gradient calculations and complexity assessments are performed in advance during the decoding phase. The decoded picture blocks are pre-processed to compute gradient values and determine complexity metrics before the actual encoding process, which accelerates subsequent coding operations by having preparation work already completed.

Different regions of the picture block are treated differently based on their local characteristics. Gradient calculations are performed selectively - full calculations are done for regions with high complexity or important features, while simplified or skipped calculations are applied to low-complexity regions, optimizing the balance between accuracy and computational load.

The calculation precision is dynamically adjusted based on the complexity metric. For picture blocks with low complexity, simplified gradient calculations or pre-determined modes are used. For high-complexity blocks, full gradient calculations are performed. This adaptive parameter change reduces overall computational complexity while maintaining accuracy where needed.

Candidate modes are pre-sorted and ranked based on complexity metrics and gradient calculations performed during the decoding phase. The most promising modes are identified in advance, so that during encoding, only the top candidates need to be fully evaluated, significantly reducing the number of mode comparisons required while maintaining coding precision.

Instead of evaluating all possible candidate modes exhaustively, the method evaluates only a subset of the most promising modes based on preliminary complexity assessment. This partial evaluation approach achieves sufficient coding precision without the excessive time cost of complete mode exhaustion, particularly for low-complexity picture blocks where fewer modes need consideration.