Video Encoding Power Optimization via Rate-Distortion Analysis

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Solution Overview

Problem

Conventional video encoders in portable devices face high power consumption due to motion estimation, which is not optimized for limited power resources, leading to suboptimal rate-distortion values and inefficient power-bit-rate-visual quality tradeoffs.

Innovation Solution

A method that computes a power-rate-distortion value by estimating the power consumption of video processing devices during the encoding process, allowing the selection of power-friendly prediction functions to balance power consumption, bit-rate, and visual quality by incorporating power consumption into the rate-distortion criterion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional motion estimation is used in portable video encoders, then encoding capability is provided, but power consumption becomes excessively high

Engineering Contradiction:
Improvepower consumptionVSAvoidencoding capability
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent applies dynamics by making the prediction function selection adaptive and variable rather than fixed. The encoder dynamically selects from multiple prediction functions (spatial, temporal, gradient, Laplacian) based on local image characteristics and rate-distortion optimization, allowing the system to adapt its power consumption and encoding capability to the specific content being encoded.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by introducing a new rate-distortion criterion that incorporates power consumption as an additional parameter alongside traditional distortion metrics. This modified criterion enables the system to optimize for both encoding quality and power efficiency simultaneously, resolving the contradiction between these two objectives.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional rate-distortion optimization is used, then encoding quality is optimized, but power consumption is not considered leading to suboptimal performance in portable devices

Engineering Contradiction:
Improveencoding qualityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent modifies the rate-distortion optimization criterion by adding power consumption as a third parameter to the traditional rate-distortion tradeoff. This extended criterion allows the system to simultaneously optimize for encoding quality, bit rate, and power consumption, ensuring reliable encoding performance while respecting power constraints in portable devices.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by using the computed rate-distortion-power value to guide the selection of prediction functions. The system evaluates multiple prediction functions, computes their respective costs including power consumption, and selects the function that minimizes the overall criterion, creating a closed-loop optimization process.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple prediction functions are evaluated to improve quality, then encoding accuracy increases, but computational complexity and power consumption increase

Engineering Contradiction:
Improveencoding accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the prediction function selection into distinct categories (spatial, temporal, gradient, Laplacian) and further segmenting the optimization process by evaluating functions separately for different block types and motion characteristics. This structured approach manages computational complexity while maintaining encoding accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by selectively applying different prediction functions to different blocks based on their characteristics, rather than uniformly applying the most accurate function to all blocks. This approach achieves sufficient encoding accuracy for each local region while reducing overall computational complexity and power consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS7978764B2Method of video encoding for handheld apparatuses selecting best prediction function according to optimal rate-distortion value
Publication Date: 2011.07.12 NXP BV
  • US7978764B2 patent drawing
  • US7978764B2 patent drawing
  • US7978764B2 patent drawing

AI summary

The present invention relates to a method of encoding a sequence of pictures, a picture being divided into blocks of data, said encoding method comprising the steps of:—computing a residual error block from a difference between a current block contained in a current picture and a candidate area using of a prediction function,—computing an entropy of the residual error block,—computing an overall error between said current block and said candidate area,—estimating a power consumption of a video processing device adapted to implement said prediction function,—computing a rate-distortion value on the basis of the entropy, the overall error and the estimated power consumption of the video processing device,—applying the preceding steps to a set of candidate areas using a set of prediction functions in order to select a prediction function according to the rate-distortion value.