Remote Watermark Timestamping for Copyright Protection
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Solution Overview
Problem
The challenge is to protect media programs from unauthorized copying and distribution during their theatrical release phase, where remote transmission is desired but requires effective copyright protection, especially using customer equipment like DVRs and STBs, while ensuring compatibility with encryption schemes.
Innovation Solution
A method and apparatus for remotely time-stamping a media program and generating a second watermark with a higher temporal resolution, allowing identification of the device that made an illegal copy and the date/time of copying, using a receiver with a tuner, video storage, and a watermark module to compute and embed the second timestamp in the media program.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital watermarking is applied to media programs before distribution, then copyright protection is improved, but the ability to track and identify illegal copies with precise timing information deteriorates
Solution Approach 1:
The system performs preliminary actions by embedding a first watermark with a first timestamp at the headend before the media program reaches the customer's receiver. This preliminary watermark serves as a reference that travels with the media program. When the receiver retrieves the program, it compares the current time with the embedded timestamp to calculate a time difference, which is then used to generate a second watermark with enhanced timing precision. This preliminary action enables subsequent precise timing identification without requiring the original high-precision timestamp to be embedded directly at the headend.
Solution Approach 2:
The watermarking process is segmented into two distinct stages: a first watermarking stage at the headend that embeds a preliminary timestamp, and a second watermarking stage at the receiver that generates a refined timestamp based on the time difference calculation. This segmentation allows each stage to perform its specific function optimally - the headend handles initial protection while the receiver handles precise timing identification, resolving the contradiction between protection reliability and timing precision.
2Productivity
If remote transmission of media programs is provided during theatrical release, then viewership is improved, but copyright protection deteriorates due to unauthorized copying
Solution Approach 1:
The system implements feedback by having the receiver calculate the time difference between the embedded first timestamp and the current local time, then use this calculated difference to generate a second watermark with enhanced timing precision. This feedback loop enables the system to adapt the watermarking to the specific timing conditions at the receiver, creating a feedback mechanism that strengthens copyright protection while allowing remote transmission to proceed.
Solution Approach 2:
The system changes the temporal resolution parameter of the timestamp from the first temporal resolution (coarser) to a second temporal resolution (finer) that is greater than the first. This parameter change occurs at the receiver based on the calculated time difference, allowing the system to maintain copyright protection reliability while enabling remote transmission during the theatrical release period.
3Device complexity
If a first watermark with lower temporal resolution is embedded at the headend, then device complexity is reduced, but the ability to identify copy timing deteriorates
Solution Approach 1:
The headend performs a relatively simple preliminary action by embedding a first watermark with a first timestamp at a lower temporal resolution. This simplifies the headend processing complexity. The more complex time difference calculation and second watermark generation is deferred to the receiver, which has the local time information needed to perform the calculation. This division of labor resolves the contradiction between headend complexity and timing identification capability.
Solution Approach 2:
The system transitions from a single-dimensional timestamp embedding approach to a two-dimensional approach where the first timestamp provides a reference point and the time difference calculation provides additional timing dimensionality. This dimensional change enables precise copy timing identification without requiring the headend to embed high-precision timestamps directly, thus reducing headend complexity while improving timing identification.
Data Source
AI summary
A method and apparatus for placing a time stamp in a remotely applied watermark is disclosed. The method permits a time stamp of high resolution to be added remotely while minimizing the number of bits necessary in the time stamp.