Media Time Mapping via Low-Rate Fingerprint Interpolation

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Solution Overview

Problem

Media clients struggle to perform frame-accurate content revisions in media streams due to a lack of context for the revision time point, especially when generating query fingerprints at a low rate, leading to inaccurate synchronous lock between true time and client time.

Innovation Solution

Implement fingerprint matching with interpolation to establish an improved mapping between true time and client time by taking into account multiple detected matching points and performing linear regression on a scatter plot of these points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fingerprint matching is performed at low rate to conserve resources, then device complexity and energy consumption are reduced, but measurement precision and reliability of time mapping deteriorate

Engineering Contradiction:
Improvefingerprinting system complexityVSAvoidtime mapping accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary fingerprint matching at low rate to identify candidate matching points, then applies linear regression interpolation to establish accurate time mapping. This preliminary action allows the system to achieve frame-accurate content revision without continuous high-rate fingerprinting, thereby reducing device complexity while maintaining precision through mathematical interpolation of the detected matching points.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If fingerprint matching is performed at low rate, then energy consumption is reduced, but reliability of synchronous lock deteriorates

Engineering Contradiction:
Improveclient energy consumptionVSAvoidsynchronous lock reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system uses linear regression to analyze the relationship between true time and client time based on detected matching points, creating a feedback mechanism that continuously refines the time mapping. This feedback approach allows the system to maintain reliable synchronous lock with low-rate fingerprinting by mathematically compensating for the reduced sampling frequency, thereby reducing energy consumption while preserving reliability.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple matching points are detected and linear regression is performed, then time mapping accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvetime mapping accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex continuous fingerprint matching with a simplified discrete approach: detect matching points at low rate, then use linear regression (a mathematical computation) to establish accurate time mapping. This substitution of mechanical/processing complexity with mathematical interpolation achieves high precision while keeping device complexity manageable, as linear regression is computationally efficient compared to continuous high-rate fingerprinting.

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

Data Source

PatentEP3824641B1Establishment and use of time mapping based on interpolation using low-rate fingerprinting, to help facilitate frame-accurate content revision
Publication Date: 2026.03.11 ROKU INC
  • EP3824641B1 patent drawingFigure 1
  • EP3824641B1 patent drawingFigure 2
  • EP3824641B1 patent drawingFigure 3

AI summary

A media client ascertains a plurality of matching points between (i) query fingerprints representing a media stream being received by the client and (ii) reference fingerprints, each identified matching point defining a respective match between a query' fingerprint that is time stamped with client time defined according to a clock of the client and a reference fingerprint that is time stamped with true time defined according to a timeline within a known media stream. Further, the client performs linear regression based on the timestamps of the ascertained plurality of matching points, to establish a mapping between true time and client time. The client then uses the established mapping as a basis to determine a client-time point at which the client should perform an action with respect to media stream, being received by the client. And the client performs the action at the determined client-time point.