H.264 Intra Prediction Scan Reordering for Parallel Block Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The H.264 image coding system experiences downtime and interference with parallelization (pipelining) due to the sequential processing of blocks in the default zigzag raster scan order, which restricts the speedup of coding and requires non-standard prediction modes or static values to avoid interference.
Innovation Solution
The image coding apparatus processes blocks using intra prediction modes specified in the H.264 standard in an order different from the default raster scan order, allowing for parallelization while ensuring compatibility with H.264 decoding standards by rearranging blocks using a control unit and sorting buffer to maintain compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blocks are processed in the default zigzag raster scan order, then compatibility with H.264 decoding standards is maintained, but parallelization (pipelining) is interfered with and processing speed is reduced
Solution Approach 1:
The patent divides the macroblock into multiple 4x4 pixel blocks and processes them in different pipelines based on their position. By segmenting the processing into multiple independent paths (first pipeline for blocks 0-7, second pipeline for blocks 8-15), the system enables parallelization while maintaining standard compliance through proper ordering within each segment.
Solution Approach 2:
The patent introduces a new dimension to the processing order by using multiple pipelines operating in parallel rather than a single sequential pipeline. This dimensional change allows simultaneous processing of different block segments, transforming the single-threaded zigzag scan into a multi-threaded approach that achieves parallelization.
2Productivity
If non-standard prediction modes or static values are used to avoid interference, then parallelization is enabled, but compatibility with standard H.264 decoding is lost
Solution Approach 1:
The patent performs preliminary reordering of blocks into two groups (0-7 and 8-15) before processing, and maintains this ordering throughout the parallel pipelines. This preliminary action ensures that when blocks are decoded, they follow the standard H.264 raster scan order, guaranteeing compatibility with standard decoders while enabling parallel processing.
Solution Approach 2:
The patent introduces an intermediary ordering mechanism that mediates between the parallel processing requirement and the standard decoding requirement. By using a consistent block ordering scheme across both pipelines that matches the H.264 standard, it acts as a bridge allowing parallel execution without sacrificing decoding compatibility.
3Productivity
If sequential processing is used to maintain standard compliance, then decoding compatibility is ensured, but downtime increases and processing efficiency is reduced
Solution Approach 1:
The patent eliminates downtime by ensuring continuous useful action in both pipelines. By organizing blocks so that both the first pipeline (blocks 0-7) and second pipeline (blocks 8-15) can process their respective blocks continuously without waiting for reference blocks from the other pipeline, the system maintains full utilization of processing resources.
Solution Approach 2:
The patent introduces dynamic parallel processing where multiple pipelines operate simultaneously with different block segments. This dynamic approach allows the system to adaptively process multiple blocks in parallel based on their positional relationships, eliminating the static sequential processing bottleneck and reducing overall processing time.
Data Source
AI summary
An image coding apparatus that makes possible the parallelization of intra prediction, and outputs coded data that can be decoded by an image decoding apparatus compliant with the H.264 standard. The image coding apparatus performs orthogonal transformation, quantization, inverse quantization, inverse orthogonal transformation, and intra prediction on all blocks obtained when a single macroblock is divided into plural blocks, and includes: a predicted block control unit that causes all of the blocks to be intra predicted using at least one of the intra prediction modes specified in the H.264 standard on at least some of the blocks, in an order different from the raster scan order specified in the H.264 standard; and an sorting buffer that outputs, in the raster scan order, all the blocks intra predicted under the control of the predicted block control unit.