Digital TV Video Fingerprinting via Pre-Processing and Forensic Luring
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Solution Overview
Problem
Current digital TV security measures, such as conditional access and watermarking, are vulnerable to attacks, particularly in untrusted user domains, where malicious users can compromise systems and distribute decrypted content, and existing watermarking techniques are cumbersome or ineffective against signal processing and format changes.
Innovation Solution
A method combining pre-fingerprinting and forensic luring processes to embed a unique identifier in audiovisual content, modifying elements with alternate values to create a fingerprinted data object that is robust against signal processing and format changes, while minimizing perceptual degradation and ensuring synchronization with existing multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If watermarking techniques are deployed to identify malicious users, then security is improved, but device complexity and process complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-processing the audiovisual content to identify modifiable elements and prepare alternate values before the actual watermarking process. This pre-fingerprinting phase creates a mapping between content elements and their alternative representations, which simplifies the subsequent watermark embedding process and reduces computational complexity during content distribution.
Solution Approach 2:
The patent segments the watermarking process into distinct phases: pre-fingerprinting (identifying modifiable elements and preparing alternate values), watermark embedding (selecting and applying alternate values based on fingerprint data), and forensic analysis (detecting and extracting watermarks). This segmentation allows each phase to be optimized independently, reducing overall process complexity.
2Measurement precision
If unique identifiers are embedded in compressed content, then user identification capability is improved, but manufacturing precision and measurement precision requirements increase
Solution Approach 1:
The patent changes parameters by working in the compressed domain rather than the original uncompressed domain. By identifying modifiable elements in the compressed bitstream and using alternate values that maintain compression efficiency, the system achieves precise watermark embedding without requiring high-precision operations on uncompressed data, thus reducing manufacturing precision requirements while maintaining identification capability.
Solution Approach 2:
The patent introduces an intermediary layer of compressed representation between the original content and the watermark embedding process. The compressed bitstream serves as an intermediary that allows watermark insertion through modification of syntax elements and data packets, reducing the precision requirements compared to direct manipulation of uncompressed audio-visual data while maintaining sufficient identification precision.
3Reliability
If watermarking is performed at the client side to identify decrypted devices, then security tracing is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the client-side device to autonomously perform watermark embedding using its own fingerprint data. The device identifies modifiable elements in the received content, selects appropriate alternate values based on its unique identifier, and embeds the watermark without requiring complex external processing infrastructure, thus improving security tracing while limiting the increase in device complexity to essential functions only.
4Stability of the object's composition
If content elements are modified with alternate values to embed identifiers, then robustness against signal processing is improved, but content quality and perceptual degradation increase
Solution Approach 1:
The patent applies local quality by selectively modifying only specific modifiable elements in the content that are least perceptible to human senses. By identifying elements such as syntax parameters and data packets that can be altered without affecting perceptual quality, and by using alternate values that maintain local content characteristics, the system achieves robustness against signal processing while minimizing overall content quality degradation.
Data Source
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AI summary
The present application concerns the field of digital TV, particularly a method to trace the origin of a (illegally) distributed video material. It is proposed a method for fingerprinting a data object A having a nominal stream format F, to provide a fingerprinted data object B, comprising the pre-fingerprinting and forensic luring process, wherein the said pre-fingerprinting process comprising the steps of: - Determining elements, having each respectively an original value and a position within the said original data object (A), - Replacing each original value by an alternate value to create a modified data object C, - Extending the said modified data object C with one supplementary object Ss to provide a fingerprinting-ready data object D, said supplementary object Ss comprising, for each element, a subset object comprising the positions to locate the elements, a first and a second replacement value; the said forensic luring process comprising the steps of: - Extracting the supplementary object (Ss) from the fingerprinting-ready data object (D), and identifying the said modified elements within the said fingerprinting-ready data object D as well as the positions with the aid of the said supplementary objects (Ss), - Obtaining an identifier to be associated with the fingerprinted data object, - Modifying the alternate values at positions in the elements, and for each element selecting one of the replacement values based on all or part of the identifier to create the fingerprinted data object.