Watermarking Intermediary Segment for Fragment Alignment

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Solution Overview

Problem

Existing content distribution methods using fragment-based watermarking suffer from symbol overflow due to misalignment between watermarking periods and fragment lengths, leading to suboptimal detection results and false symbol detection, as the detector needs side information to align fragments correctly.

Innovation Solution

Incorporating an intermediary segment of at least maximum fragment length between watermarking periods ensures no symbol overflow, allowing for blind detection by using a common alphabet for multiple copies of segments and embedding a reference watermark or avoiding watermarking in the intermediary segment to prevent false payload detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If watermarking periods are fixed in position, then watermark embedding is simplified, but symbol overflow occurs when fragments misalign with watermarking periods

Engineering Contradiction:
Improvewatermark embedding simplicityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediary segment between watermarking periods that acts as a buffer to prevent symbol overflow. This intermediary segment is at least as long as the maximum fragment length, ensuring that fragments cannot span across multiple watermarking periods and causing symbol overflow. The intermediary segment effectively mediates between the fixed watermarking periods and the variable fragment boundaries.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If fragment-based distribution is used, then content distribution flexibility and adaptability are improved, but symbol overflow causes false detection and requires informed detectors

Engineering Contradiction:
Improvedistribution flexibilityVSAvoiddetector complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The intermediary segment serves as a delimiter that allows blind detection without requiring the detector to know fragment boundaries or watermarking period alignments. By inserting this buffer segment, the system enables adaptability in fragment-based distribution while simplifying the detector design, as the intermediary segment provides clear boundaries for detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the alignment problem from the watermarking process by removing the dependency between fragment boundaries and watermarking periods. The intermediary segment is extracted as a separate element that absorbs the misalignment, allowing the watermarking and fragmenting processes to operate independently without synchronization.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If multiple copies of segments are watermarked with different symbols, then detection reliability is improved, but false payload detection may occur without proper alignment

Engineering Contradiction:
Improvedetection reliabilityVSAvoidfalse payload detection
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The intermediary segment prevents false payload detection by ensuring that each fragment contains symbols from only one watermarking period. This buffer segment acts as a barrier that prevents symbols from adjacent periods from being conflated, thereby maintaining the integrity of the payload information when multiple copies with different symbols are used.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3022943B1Method and system for watermarking content prior to fragmenting
Publication Date: 2020.05.20 NAGRAVISION SA
  • EP3022943B1 patent drawingFigure 1
  • EP3022943B1 patent drawingFigure 2~3
  • EP3022943B1 patent drawingFigure 4~5

AI summary

In a method of distributing content in plural fragments, each fragment being no longer than a given maximum fragment length, a method of watermarking the content prior to fragmenting the content into the plural fragments, comprising watermarking a given payload symbol from a given alphabet in a given segment of the content, and treating a segment prior to or following the given segment as an intermediary segment, the length of this intermediary segment being substantially equal to or greater than the maximum fragment length.