Video Encoding Complexity Optimization via Description Length

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Solution Overview

Problem

Conventional video encoding strategies fail to maintain constant visual quality while meeting bitrate constraints, leading to inefficient allocation of coding bits and computations in video transcoding for hosting services.

Innovation Solution

A method that measures video complexity using video description length (VDL) to adjust encoding complexity and employs a trained CRF reference bitrate model for optimized transcoding, ensuring constant quality and bitrate through a revised CRF-bitrate model.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional encoding strategies (ABR, CBR, CQP, CRF) are used, then encoding speed or bitrate control is improved, but visual quality consistency deteriorates

Engineering Contradiction:

Improveencoding speedVSAvoidvisual quality consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the quantizer adaptive rather than static. The quantizer is adjusted frame-by-frame based on local complexity measures (variance, gradient magnitude, motion activity) to maintain constant visual quality while adapting to scene changes, resolving the contradiction between encoding speed and visual quality consistency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by applying different quantizer values to different regions and frames based on their complexity. High-complexity regions receive finer quantization (lower QP) while low-complexity regions use coarser quantization (higher QP), maintaining visual quality consistency without uniformly increasing bitrate

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If conventional encoding strategies are used, then bitrate control is improved, but rate-distortion optimization deteriorates

Engineering Contradiction:

Improvebitrate controlVSAvoidrate-distortion performance

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes parameters dynamically by adjusting the quantizer based on local complexity metrics rather than using fixed or globally adaptive parameters. This allows optimal rate-distortion performance by matching compression intensity to actual content requirements, improving R-D efficiency while maintaining bitrate control

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback mechanisms where encoding statistics and complexity measures from previous frames inform quantizer decisions for current frames. This closed-loop approach optimizes rate-distortion performance by continuously adapting to content characteristics while meeting bitrate constraints

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If CRF encoding with varying scenes is used, then visual quality consistency is improved, but bitrate predictability deteriorates

Engineering Contradiction:

Improvevisual quality consistencyVSAvoidbitrate predictability

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by performing a first pass encoding to gather complexity statistics and determine appropriate quantizer values before the final encoding pass. This pre-analysis allows accurate bitrate prediction and control while maintaining constant visual quality, resolving the contradiction between quality consistency and bitrate predictability

Inventive Principle:

Principle #10Preliminary action

4Quantity of substance

If ABR encoding with scaling factors is used, then bitrate target achievement is improved, but visual quality stability deteriorates

Engineering Contradiction:

Improvebitrate target achievementVSAvoidvisual quality stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent implements local quality by applying region-specific quantizer adjustments based on measured complexity rather than uniform scaling. This maintains visual quality stability across scene changes while achieving bitrate targets through localized compression intensity variations

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9225983B2Rate-distortion-complexity optimization of video encoding guided by video description length

Publication Date: 2015.12.29 GOOGLE LLC

AI summary

A system and method provide a video description length (VDL) guided constant quality video encoding strategy with bitrate constraint and a video coding system for optimizing encoding bitrate, distortion and complexity of an input video. The method obtains an overall VDL, temporal VDL and spatial VDL of the input video and compares the overall VDL, temporal VDL and spatial VDL of the input video with a reference VDL, temporal VDL and spatial VDL. Based on the comparison, the method adjusts the encoding bitrate, the overall encoding complexity, temporal encoding complexity and spatial encoding complexity of the input video and encodes the input video with the adjusted encoding bitrate, overall encoding complexity, temporal encoding complexity and spatial encoding complexity of the input video.