Inverse AC-DC Predictor for Video Coding
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Solution Overview
Problem
Existing digital video coding technologies, such as MPEG-4, face challenges in implementing efficient AC-DC prediction for low bandwidth applications, particularly in portable wireless devices with power and computing constraints, where complex prediction methods are not feasible.
Innovation Solution
A method for video encoding and decoding that uses an inverse AC-DC predictor to determine the direction of change in intra blocks by accessing quantized DC values from neighboring blocks, reconstructing quantized DC and AC values without division operations, and utilizing fixed quantization parameters to simplify the prediction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional AC-DC prediction methods are used in MPEG-4, then video compression efficiency is improved, but computational complexity and power consumption increase significantly
Solution Approach 1:
The patent changes the parameters of the prediction method by using a simplified AC-DC prediction algorithm specifically optimized for low-bandwidth applications. This involves modifying how prediction values are calculated and applied, reducing the computational burden while maintaining acceptable compression efficiency for portable devices
Solution Approach 2:
The patent applies partial action by implementing a reduced complexity prediction process that does not fully exhaust all possible prediction paths. It uses selective prediction based on available neighboring blocks and predefined parameters, avoiding unnecessary computational steps while achieving sufficient compression for the target application
2Measurement precision
If complex prediction methods are implemented, then prediction accuracy is improved, but power consumption increases
Solution Approach 1:
The patent modifies the energy consumption characteristics by changing the computational parameters of the prediction algorithm. It uses simplified calculations with predefined quantization parameters and reduced complexity operations that consume significantly less power while maintaining adequate prediction accuracy for low-bandwidth video applications
Solution Approach 2:
The patent employs disposable or temporary prediction values that are calculated on-demand and discarded after use, rather than maintaining complex persistent prediction structures. This approach reduces the energy burden by using lightweight, single-use prediction mechanisms that can be quickly recomputed without requiring powerful computational resources
3Measurement precision
If division operations are used in quantization, then prediction precision is improved, but computational complexity increases
Solution Approach 1:
The patent replaces the mechanical division operation with an alternative quantization mechanism. Instead of using division to calculate quantized values, it employs multiplication by predefined reciprocal values or lookup tables that provide equivalent precision without requiring division hardware, significantly reducing computational complexity
Solution Approach 2:
The patent changes the quantization parameters by using fixed quantization values and predefined scaling factors that eliminate the need for dynamic division operations. This parameter transformation allows the system to achieve sufficient quantization precision through simpler arithmetic operations, reducing the computational burden on portable devices
Data Source
AI summary
Digital signal processing and, more particularly, digital video coding is described. Video encoding or decoding of frames includes accessing a plurality of values that can include at least one quantized DC default value and a plurality of quantized DC block values for neighboring blocks with respect to an intra block. A direction of change for the intra block is determined using predictor values obtained from the accessed values.