VLC Coefficient Coding for Large Chroma Blocks
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Solution Overview
Problem
Current video coding standards, such as HEVC, lack a dedicated coefficient coding scheme for chroma blocks larger than 8×8, leading to data loss and inefficiency in compression, as they rely on truncating and coding only the first 64 coefficients using the same scheme for 8×8 blocks.
Innovation Solution
A dedicated coding scheme for chroma blocks of size greater than 8×8 is introduced, which adaptively updates the VLC table index value based on the code number and scaling factor for luma blocks, while for chroma blocks, the VLC table index is updated solely based on the code number, minimizing memory resources and reducing data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same VLC coding scheme for 8×8 blocks is used for chroma blocks larger than 8×8, then implementation simplicity is maintained, but data loss occurs and compression efficiency deteriorates
Solution Approach 1:
The patent segments the chroma block processing into two distinct paths: one for blocks ≤8×8 using the existing VLC scheme, and another for blocks >8×8 using a dedicated coding scheme. This segmentation allows the system to maintain simplicity for small blocks while achieving improved compression and reducing data loss for larger chroma blocks through specialized processing.
2Productivity
If a dedicated coding scheme for chroma blocks larger than 8×8 is introduced, then compression efficiency is improved and data loss is reduced, but device complexity increases
Solution Approach 1:
The patent implements dynamic complexity management by conditionally applying different coding schemes based on block size. The system dynamically selects between the simple VLC scheme for small blocks and the more complex dedicated scheme for large blocks, ensuring that increased complexity is only introduced when necessary to achieve compression efficiency improvements.
Solution Approach 2:
The patent applies local quality by using different coding approaches for different regions (block sizes) of chroma data. Small chroma blocks use the standard VLC scheme while large chroma blocks use the dedicated coding scheme, allowing each region to be processed with the most appropriate method for its specific characteristics, thereby improving overall compression efficiency without uniformly increasing complexity across all blocks.
3Quantity of substance
If transform coefficients are truncated to 64 coefficients for chroma blocks, then memory resources are reduced, but manufacturing precision and data integrity are compromised
Solution Approach 1:
The patent applies preliminary action by performing optimized VLC coding on all transform coefficients before any potential truncation or memory storage. The dedicated coding scheme processes coefficients in an order and manner that prioritizes preserving the most significant data, allowing the system to achieve better data integrity with reduced memory requirements compared to naive truncation approaches.
Data Source
AI summary
This disclosure describes techniques for coding transform coefficients for a block of video data. According to these techniques, a video coder (a video encoder or video decoder) determines whether a block of video data is a luma block or a chroma block. If the block of video data is a luma block, the video coder adaptively updates a VLC table index value based on a code number cn and value of a scaling factor. However, if the block of video data is a chroma block, the video coder adaptively updates the VLC table index value based on the code number cn and without using the scaling factor. The video coder uses the updated VLC table index value to select a VLC table of a plurality of VLC tables that are used to encode or decode the block of video data.