Transcoding-Resistant Watermarking via Entropy-Based Frequency Band Selection
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Solution Overview
Problem
Existing digital watermarking techniques are susceptible to distortion during transcoding, requiring separate watermarking for each device format, leading to redundancy, increased processing overhead, and computational complexity.
Innovation Solution
A method and system for transcoding-resistant watermarking that identifies and inserts watermarks in high information regions of digital media content before transcoding, using spectral frequency bands and metrics like entropy and feature density to select optimal regions for watermarking, ensuring the watermark remains intact across different formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If watermark is inserted into original media content before transcoding, then watermark robustness against transcoding is improved, but watermark distortion during transcoding occurs
Solution Approach 1:
The patent applies local quality by selectively embedding watermark data in specific frequency bands (particularly high-frequency bands) rather than uniformly across all frequencies. This localized approach ensures that watermark information is placed in regions that are more resilient to transcoding operations, thereby maintaining watermark robustness while minimizing distortion.
Solution Approach 2:
The patent utilizes parameter changes by transforming the watermark embedding process from spatial domain to frequency domain (using DCT or wavelet transforms). This parameter transformation allows the watermark to be embedded in a representation that is more invariant to transcoding operations, resolving the contradiction between robustness and integrity.
2Measurement precision
If separate watermarking is performed for each device format after transcoding, then watermark accuracy for each device is improved, but processing overhead and computational complexity increase
Solution Approach 1:
The patent implements universality by creating a single watermarked version of the media content that can be universally used across multiple device formats. The frequency-domain embedding technique ensures that the watermark survives various transcoding operations, making one watermarked copy suitable for multiple devices, thereby eliminating the need for separate watermarking processes for each format.
Solution Approach 2:
The patent applies preliminary action by performing watermark embedding once on the original media content before any device-specific transcoding occurs. This preliminary watermarking ensures that the watermark is already in place and protected when the content is later transcoded for different devices, eliminating the need for repeated watermarking operations.
3Ease of manufacture
If watermark is embedded in spatial domain, then implementation simplicity is improved, but watermark susceptibility to transcoding distortion increases
Solution Approach 1:
The patent substitutes the mechanical spatial-domain embedding approach with a frequency-domain transformation approach (using DCT or wavelet transforms). This substitution replaces the simple but vulnerable spatial embedding mechanism with a transformed domain approach that maintains mathematical simplicity while providing transcoding resistance through frequency-selective embedding.
Data Source
AI summary
A method for performing transcoding resistant watermarking of digital media content is provided. The method enables obtaining a plurality of spectral frequency bands of the digital media content. The method further enables calculating an entropy value for each of the plurality of spectral frequency bands. The entropy value quantifies information in each of the plurality of spectral frequency bands. The method further enables selecting a spectral frequency band from amongst the plurality of spectral frequency bands based on the calculation. The selected spectral frequency band has the highest entropy. Furthermore, the method enables inserting a watermark in the selected spectral frequency band of the digital media content.