Video Stream Latency Measurement with Feature Correlation

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Solution Overview

Problem

Existing methods for real-time latency measurement between video streams are cumbersome and time-consuming, often involving manual frame alignment or complex frame-based measurements that are impractical.

Innovation Solution

A feature-based technique using spatial and temporal information extraction and correlation analysis is employed to synchronize and measure latency between video streams, utilizing filters like Gaussian and Laplacian filters, and correlation metrics such as Pearson Linear Correlation Coefficient to align and calculate latency accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual frame alignment or frame-based measurement is used, then measurement precision is improved, but productivity deteriorates

Engineering Contradiction:
Improvelatency measurement precisionVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts and analyzes only specific key features (spatial information, temporal information, motion vectors) from video frames rather than processing entire frames. This selective extraction maintains measurement precision while significantly reducing computational complexity and improving measurement speed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the video frame analysis into distinct feature components (spatial features, temporal features, motion vectors) that can be processed independently and efficiently. This segmentation allows for optimized computation of each feature type, resolving the contradiction between precision and speed.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If manual frame alignment is used, then measurement precision is improved, but device complexity deteriorates

Engineering Contradiction:
Improvelatency measurement precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual visual frame alignment with an automated computational system that uses feature extraction and correlation analysis. This substitution eliminates the need for human operators while maintaining or improving measurement precision, and the systematic approach actually reduces overall complexity compared to manual procedures.

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

3Measurement precision

If frame-based measurement is used, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvelatency measurement precisionVSAvoidoperational simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements a self-service measurement system that automatically performs feature extraction, correlation analysis, and latency calculation without requiring manual frame-by-frame inspection. The system autonomously identifies corresponding frames and computes latency, making the operation simple while maintaining high precision through rigorous feature-based comparison.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4111697B1Real-time latency measurement of video streams
Publication Date: 2025.08.20 IMAX CORP
  • EP4111697B1 patent drawingFigure 1
  • EP4111697B1 patent drawingFigure 2
  • EP4111697B1 patent drawingFigure 3

AI summary

Frames of a video stream collected at first and second points along a video delivery chain are buffered into first and second buffers, respectively, the second point being downstream the video delivery chain from the first point. A control group is identified as a subset of frames of the second buffer. Correlations of extracted features of the control group to extracted features of successive windows of frames of the first buffer are computed, the extracted features being based on spatial information and temporal information of the video stream. A delay between the video stream collected at the first point and the video stream collected at the second point is identified according to a maximum correlation of the correlations.