BDPCM Residual Block Detection in VVC Video Encoding
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Solution Overview
Problem
Current video encoding and decoding methods using the block differential pulse code modulation (BDPCM) mode in Versatile Video Coding (VVC) have low efficiency due to the need to encode and decode transform tree syntax structures for residual blocks, even when they contain no non-zero transform coefficients.
Innovation Solution
A method and apparatus that decode intra-frame prediction mode information and identification information for a current decoding unit, determining if a transform block has non-zero coefficients, allowing for the direct determination of an all-zero residual block and omitting the need to encode or decode transform tree syntax structures when no non-zero coefficients are present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If transform tree syntax structures are encoded and decoded for residual blocks in BDPCM mode, then the residual block information is completely represented, but the encoding and decoding efficiency deteriorates due to unnecessary processing of all-zero residual blocks
Solution Approach 1:
The patent extracts and identifies all-zero residual blocks using a specific flag, separating them from normal residual blocks that require transform tree syntax structures. This allows the encoding system to take out the unnecessary transform tree encoding step for all-zero blocks while preserving complete information representation for non-zero blocks.
Solution Approach 2:
Instead of applying the full transform tree syntax structure encoding process to all residual blocks, the patent applies partial action by using a simplified flag-based indication only for all-zero residual blocks. This reduces the excessive processing overhead while maintaining sufficient information for accurate reconstruction.
2Manufacturing precision
If transform tree syntax structures are decoded for all residual blocks, then accurate residual block reconstruction is achieved, but the decoding time and computational complexity increase unnecessarily for all-zero blocks
Solution Approach 1:
The patent performs preliminary identification of all-zero residual blocks using a dedicated flag before the actual reconstruction process. This preliminary action allows the decoder to skip the computationally intensive transform tree syntax structure decoding step for all-zero blocks, thereby reducing decoding time without compromising reconstruction accuracy.
Solution Approach 2:
Instead of using the traditional approach where transform tree syntax structures are always decoded to determine residual block content, the patent inverts the logic by using a flag to directly indicate when the residual block is all-zero, eliminating the need for full syntax structure decoding in those cases.
3Productivity
If BDPCM mode is used for encoding, then compression efficiency is improved for certain block types, but the overall encoding complexity increases due to additional mode checking and syntax structure handling
Solution Approach 1:
The patent extracts the essential information needed for all-zero residual blocks (the presence flag) and removes the unnecessary transform tree syntax structures from the encoding process for these blocks. This reduces encoding complexity while maintaining compression efficiency for BDPCM mode.
Solution Approach 2:
The patent changes the parameter representation for all-zero residual blocks from full transform tree syntax structures to a simple flag indicator. This parameter change simplifies the encoding process and reduces the computational complexity associated with BDPCM mode handling.
Data Source
AI summary
A video encoding method is provided. The method includes decoding intra-frame prediction mode information corresponding to a current decoding unit, decoding first identification information corresponding to the current decoding unit when the intra-frame prediction mode information indicates that a block differential pulse code modulation (BDPCM) mode is applied to the current decoding unit, determining, when the first identification information indicates that a transform block (TB) corresponding to the current decoding unit does not include any non-zero transform coefficients, that a residual block corresponding to the current decoding unit is an all-zero residual block, and reconstructing the current decoding unit according to the residual block and a prediction block corresponding to the current decoding unit. The technical solutions provided in embodiments of this application improve the encoding and decoding efficiency of the decoding unit using the BDPCM mode. Apparatus and non-transitory computer-readable storage medium counterpart embodiments are also provided.