In-Loop Filtering for I_PCM Blocks with Selective SAO and ALF
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality videos leads to higher data volumes, resulting in increased costs for transfer and storage, necessitating more efficient video compression techniques.
Innovation Solution
Implementing an in-loop filtering method that includes deblocking filters, sample adaptive offset (SAO), and adaptive loop filters (ALF) to enhance video encoding/decoding efficiency, particularly by adapting these filters based on the intra pulse code modulation (I_PCM) mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If in-loop filtering (deblocking filter, SAO, ALF) is applied to I_PCM mode blocks, then filtering quality is improved, but encoding/decoding complexity and processing time increase
Solution Approach 1:
The patent extracts the I_PCM mode identification from the general filtering process and applies a specialized simplified filtering path for I_PCM blocks. The decoder identifies I_PCM mode blocks and applies only minimal filtering (deblocking with bS=0) while skipping SAO and ALF processes, thereby reducing complexity for this specific mode while maintaining quality for other modes.
Solution Approach 2:
The patent applies different filtering strategies to different block types based on their characteristics. For I_PCM mode blocks, a simplified deblocking process is applied (local optimization), while for non-I_PCM blocks, the full filtering chain (deblocking + SAO + ALF) is maintained. This local quality approach optimizes the overall system by tailoring processing to specific block requirements.
2Manufacturing precision
If full in-loop filtering chain (deblocking + SAO + ALF) is applied to all blocks, then video quality is improved, but processing time and computational load increase
Solution Approach 1:
The patent applies partial filtering action by selectively enabling only the necessary filtering steps for each block type. For I_PCM blocks, only deblocking is applied (partial action), while for other blocks, the full filtering chain is used. This prevents excessive processing of I_PCM blocks while maintaining quality where needed.
Solution Approach 2:
The filtering process is made dynamic by adapting the filtering strength and type based on the block mode. The decoder dynamically adjusts the filtering approach: applying strong filtering (full chain) for predicted blocks and minimal filtering (deblocking only) for I_PCM blocks. This dynamic adaptation reduces overall processing time while maintaining quality.
3Manufacturing precision
If deblocking filter is applied with high boundary strength to I_PCM blocks, then block edge artifacts are reduced, but distortion of original pixel values increases
Solution Approach 1:
The patent changes the boundary strength parameter for I_PCM blocks by setting bS=0, which fundamentally alters the deblocking behavior. This parameter change prevents the deblocking filter from modifying I_PCM pixel values while still providing minimal edge smoothing, thereby preserving pixel value accuracy while addressing block edge artifacts.
Data Source
AI summary
According to the present invention, an image-encoding method comprises the following steps: receiving image information; generating a restored block for the current block based on the image information; and generating a finally restored block for the current block by applying an in-loop filter to the restored block on the basis of the image information. According to the present invention, image-encoding/decoding efficiency may be improved.