Propagation Maps for Watermarking H.264 Video Fidelity
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Solution Overview
Problem
Digital watermarking in H.264/AVC encoded videos often introduces objectionable artifacts due to modifications in motion vectors, which can propagate and affect other blocks, leading to visual distortion and fidelity issues.
Innovation Solution
The creation and use of propagation maps to track and predict the impact of changes in motion vectors, allowing for the assessment and prevention of fidelity degradation by identifying affected blocks and their changes, thereby optimizing watermarking applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital watermarking is applied by modifying motion vectors in H.264/AVC encoded videos, then watermark embedding capability is improved, but visual distortion and fidelity degradation occur due to propagation of changes
Solution Approach 1:
The patent applies preliminary action by constructing propagation maps before watermark embedding to predict which blocks will be affected by motion vector modifications. This allows the system to pre-identify problematic areas and adjust the watermarking strategy accordingly, preventing visual distortion before it occurs rather than correcting it after watermarking.
Solution Approach 2:
The patent implements local quality by applying different watermarking strategies to different regions of the video based on their propagation characteristics. Blocks identified as high-risk through propagation map analysis receive different treatment (such as reduced watermark strength or alternative embedding methods) compared to low-risk blocks, thereby maintaining overall watermarking effectiveness while minimizing localized visual distortion.
2Measurement precision
If motion vectors are modified for watermarking, then watermark detection capability is improved, but fidelity of the video is degraded due to propagation effects
Solution Approach 1:
The patent employs feedback by using propagation map analysis results to adjust watermark embedding parameters in real-time. The system continuously monitors which blocks are affected by propagation effects and feeds this information back to the watermarking process, dynamically modifying embedding strength or location to maintain both detection capability and video fidelity.
Solution Approach 2:
The patent applies parameter changes by modifying watermark embedding parameters (such as modification depth, embedding location, or pattern) based on propagation map characteristics. Instead of using uniform watermarking parameters across all blocks, the system adapts parameters locally according to propagation risk, thereby preserving video fidelity in sensitive areas while maintaining detection capability in robust areas.
3Reliability
If propagation maps are constructed to predict changes, then artifact prevention capability is improved, but computational complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the video into slices and further into individual blocks, constructing propagation maps block-by-block rather than processing the entire video as a single unit. This segmented approach reduces the computational burden at each step while maintaining comprehensive artifact prevention coverage across the entire video sequence.
Solution Approach 2:
The patent implements partial action by constructing propagation maps selectively for only those blocks that are likely to be affected by watermarking, rather than computing propagation maps for all blocks in the video. This partial computation approach reduces overall computational complexity while still providing sufficient artifact prevention capability for the critical regions.
Data Source
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AI summary
A method comprises receiving original encoded video stream as one input, accessing encoded data divided into slices which are further divided into blocks, receiving the list of possible changes or watermarks as another input, accessing at least one block, decoding each slice, setting down each slice, extracting from the list those changes that apply to the at least one block, and constructing propagation maps from inter-prediction or intra-prediction using changes for the at least one block. The method can further comprise decoding luminance data using the propagation maps, comparing the luminance data to a fidelity threshold, and applying possible changes or watermarks to those not exceeding the fidelity threshold.