Optical Disc Copy Protection via Redundant Data Errors

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Solution Overview

Problem

Existing copy protection methods for optical discs are ineffective against devices that parse navigation data to circumvent copying restrictions, allowing unauthorized copying.

Innovation Solution

Incorporating errors into redundant control data that is not utilized during playback, causing devices that parse navigational information to fail, while ensuring normal playback remains unaffected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If errors are incorporated into redundant control data to frustrate access by copying devices, then copy protection effectiveness is improved, but device complexity increases

Engineering Contradiction:

Improvecopy protection effectivenessVSAvoidcontrol data structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control data is segmented into essential portions (used during playback) and redundant portions (not used during playback). Errors are selectively applied only to the redundant segments, allowing copy protection without affecting legitimate playback functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality requirements are applied to different parts of the control data. Essential control data maintains high accuracy for reliable playback, while redundant control data intentionally contains errors to frustrate copying devices. This local differentiation resolves the contradiction between protection effectiveness and system complexity.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If redundant control data with errors is added to the disc, then resistance to navigation-based copying is improved, but data volume increases

Engineering Contradiction:

Improveresistance to copyingVSAvoiddata volume

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The invention extracts only the necessary protective element (redundant control data with errors) from a complete copy protection system, adding minimal data volume while achieving resistance to navigation-based copying attacks.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If errors are introduced into control data to prevent copying, then copy protection is strengthened, but risk of affecting legitimate playback increases

Engineering Contradiction:

Improvecopy protection strengthVSAvoidrisk to legitimate playback

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control data is divided into functional segments: essential control data that maintains accurate pointers and navigation for legitimate playback, and redundant control data that contains intentional errors. This segmentation ensures that copying devices encountering errors cannot successfully copy, while legitimate players continue to function normally by using only the error-free essential segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality standards are applied locally within the control data structure. Essential portions maintain high quality for reliable playback, while redundant portions deliberately contain low-quality error data for copy protection. This local quality differentiation eliminates the risk to legitimate playback while strengthening copy protection.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7706661B2Copy protection of optical discs using redundant control data

Publication Date: 2010.04.27 ROVI SOLUTIONS CORP

AI summary

Subservive data has been incorporated in the content of an optical disc, such as a DVD, to prevent copying of the disc. To defeat such copy protection, devices to copy optical discs are now being controlled to only copy data referred to by selected program paths. Accordingly, it is proposed to provide copy protection for optical discs by introducing errors into redundant control data to frustrate access to content on the disc. For example, the errors may be inconsistencies in a Video Manage Information Table (VMGI) or in a Video Title Set Information Table (VTSI).