Hardware CABAC Transcoder for H.264 Latency Reduction

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Solution Overview

Problem

Conventional software-based approaches for transcoding 4×4 CAVLC residual blocks to 8×8 CABAC residual blocks in H.264 video encoding suffer from performance latency, necessitating a more efficient solution.

Innovation Solution

A hardware-based system comprising modules for parsing 4×4 CAVLC residual blocks, generating metric signals, and up-sampling to create 8×8 CABAC residual blocks, reducing latency and maintaining performance with minimal hardware implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If software-based approaches are used for transcoding 4×4 CAVLC residual blocks to 8×8 CABAC residual blocks, then implementation complexity is reduced, but latency increases and performance deteriorates

Engineering Contradiction:
Improveimplementation complexityVSAvoidtranscoding latency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The transcoding process is divided into separate functional modules: a parsing module that processes 4×4 CAVLC residual blocks and generates metric signals, and an up-sampling module that generates the 8×8 CABAC residual block. This segmentation allows each module to be optimized independently for speed while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Metric signals serve as an intermediary data structure between the parsing module and up-sampling module. These metric signals contain essential information about the residual blocks and enable fast transformation without requiring complex software processing, thus reducing latency while keeping implementation straightforward.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If hardware-based systems are implemented for transcoding, then latency is reduced and performance is maintained, but hardware area increases

Engineering Contradiction:
Improvetranscoding latencyVSAvoidhardware area
Core Design Contradiction:
Loss of timeVSArea of stationary object

Solution Approach 1:

The hardware is divided into two main modules: a parsing module that generates parsed residual blocks and metric signals, and an up-sampling module that generates the final 8×8 CABAC residual block. This segmentation reduces the hardware area required compared to a monolithic design while maintaining low latency through parallel processing capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The metric signals are extracted as a separate intermediate representation that captures essential features of the residual blocks. This extraction allows the up-sampling module to work with compact data structures, reducing hardware area requirements while enabling fast processing.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If conventional software solutions are used, then hardware resources are conserved, but performance is lost due to latency

Engineering Contradiction:
Improvehardware areaVSAvoidtranscoding performance
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

By segmenting the transcoding function into parsing and up-sampling modules, the system achieves hardware-level parallel processing capability. This segmentation enables the hardware to process multiple data elements simultaneously, dramatically improving productivity while using minimal hardware resources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the software-based mechanical processing system with a dedicated hardware circuit implementation. This substitution eliminates the latency inherent in software execution while using efficient hardware logic that consumes minimal area, thereby improving productivity without significant hardware investment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7369066B1Efficient 8×8 CABAC residual block transcode system
Publication Date: 2008.05.06 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • US7369066B1 patent drawing
  • US7369066B1 patent drawing
  • US7369066B1 patent drawing

AI summary

A circuit generally including a first module, a second module and a third module is disclosed. The first module may be configured to (i) generate a plurality of parsed residual blocks by parsing a plurality of 4×4 CAVLC (context-based adaptive variable length coding) residual blocks received in an input signal and (ii) generate a plurality of metric signals resulting from the parsing of the 4×4 CAVLC residual blocks. The second module configured to generate a plurality of scanning position signals based on the metric signals. The third module configured to generating an 8×8 CABAC (context-based adaptive binary arithmetic coding) residual block in an output signal by up-sampling the parsed residual blocks based on the scanning position signals.