Dynamic Watermarking Variable Length Code Robustness
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Solution Overview
Problem
Existing dynamic watermark systems face challenges with fixed-length bit codes that may not be robust enough for certain copying methods and raise privacy concerns due to the inclusion of MAC addresses, while also lacking flexibility in adjusting watermark length based on audience size and service type.
Innovation Solution
A dynamic watermarking system that generates a locally-unique code of variable length, based on projected audience size and service type, which does not include direct device identifiers like MAC addresses, and associates additional information with the watermark, allowing for enhanced privacy and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed-length bit codes (e.g., 24 bits, 48 bits, 60 bits) are used for dynamic watermarks, then the watermark structure is simple and easy to implement, but the robustness against certain copying methods is insufficient
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-length watermarks to variable-length watermarks. The watermark length is dynamically adjusted based on the specific copying method detected and the robustness requirements of different service types. This allows the system to optimize watermark robustness for each scenario without using a uniformly complex structure, resolving the contradiction between reliability and complexity.
2Measurement precision
If MAC address is included in the dynamic watermark, then the ability to identify the source device is improved, but privacy concerns are raised
Solution Approach 1:
The patent extracts only the necessary identifying information from the device and excludes sensitive data like MAC addresses from the watermark. Instead of embedding the full MAC address, the system uses a hashed or truncated version that maintains device identification capability while removing direct privacy-exposing elements. This resolves the contradiction between precise device tracking and user privacy protection.
3Adaptability or versatility
If a single fixed watermark length is used for all services, then the system is simple to operate, but it lacks flexibility to adapt to different audience sizes and service types
Solution Approach 1:
The patent changes the parameter of watermark length from a fixed value to a variable parameter that adapts to different service types and audience sizes. The system automatically selects appropriate watermark lengths based on pre-configured profiles for different services (e.g., shorter watermarks for small audiences, longer watermarks for large-scale distribution). This resolves the contradiction between operational simplicity and adaptability by making the parameter adjustment automatic rather than manual.
Data Source
AI summary
A dynamic watermark generation method and system in which the dynamic watermark may have a default length or a shorter length, and wherein the dynamic watermark is generated to have the determined length. The dynamic watermark is a locally-unique code that is used as an index to a database entry that identifies the subscriber that requested the media asset. In some instances, the entry may include a timestamp, a subscriber device identifier such as a MAC address or IP address, a subscriber identifier or ID number, and a media asset identifier such as a static ID. The static ID may include a code that indicates whether the dynamic watermark is of a default length or shorter. The length of the dynamic watermark may be partly based upon projected audience size for the requested media asset.