Playlist Watermarking for Adaptive Streaming Security
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Solution Overview
Problem
In adaptive streaming systems, securing digital content distributed via playlists is challenging due to the significant overhead in processing and storage required to prepare content for all possible access scenarios, especially when content is prepared for each client in multiple bitrates and maintained for the entire duration of access.
Innovation Solution
The method involves generating individualized playlists with unique watermark sequences and encryption keys for each client device, allowing selection between alternative chunks based on these sequences, and listing the selected chunks in the playlist, ensuring that content assembled using the playlist includes a unique watermark sequence and requires specific decryption keys for playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If content is prepared for each client device in multiple bitrates and maintained for the entire duration of access, then content security is improved, but processing overhead and storage requirements increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-generating multiple alternative chunks for each content section, where each chunk is encoded with different bitrates and watermarked with unique identifiers. This preparation is done in advance before client access, so that when a client requests content, the server can immediately assemble a customized playlist without real-time processing overhead. The chunks are pre-watermarked and pre-encoded, eliminating the need for complex real-time processing during content delivery.
Solution Approach 2:
The patent segments content into multiple small chunks, where each chunk represents a temporal section of the content. For each section, multiple alternative chunks are created with different encoding parameters (bitrates, resolutions). This segmentation allows the system to provide fine-grained control over content delivery, enabling efficient playlist assembly where only the necessary chunks are selected and combined for each client, rather than processing entire content files.
2Reliability
If content is prepared for each client device with unique watermark sequences, then content security is improved, but storage requirements increase significantly
Solution Approach 1:
The patent applies local quality by watermarking only specific portions (chunks) of content rather than the entire content file. Each chunk contains a localized watermark identifier that is sufficient for tracking and security purposes. This approach reduces storage requirements because the watermark information is distributed across small, manageable units rather than requiring redundant watermarking of complete content files for each client.
Solution Approach 2:
The patent uses copying by creating multiple alternative chunks from the same source content section, where each chunk is a copy of the perceptual content but with different encoding parameters and watermark identifiers. This allows the system to serve multiple clients with different quality levels while storing the base content once, reducing overall storage requirements compared to maintaining completely separate content files for each client.
3Adaptability or versatility
If multiple alternative chunks are created from every section with different encodings, then adaptability to client devices is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by enabling runtime selection of chunks based on client device characteristics and network conditions. The system dynamically assembles playlists by selecting appropriate chunks from the pre-generated alternatives, allowing adaptability to different client capabilities without requiring complex real-time encoding or processing. The dynamic aspect is in the selection and assembly phase, not in content generation.
Data Source
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AI summary
A method for generating a unique playlist by a server, where content assembled using the playlist includes a unique watermark sequence, comprises: - generating a watermark sequence, where the watermark sequence is a unique identifier for a client device; - encoding a plurality of alternative groups (220, 230) of chunks of encoded content for each of a plurality of sections of a piece of content, where each of the alternative groups of chunks contains a plurality of chunks having different embedded digital watermark information (210, 215) from chunks in another alternative group of chunks, and where each chunk within an alternative group of chunks includes the same perceptual content encoded using the same embedded digital watermark information but encoded at a different bitrate as another chunk within the alternative group of chunks; - selecting an alternative group of chunks based upon the watermark sequence; - listing the selected chunks in a playlist in accordance with the watermark sequence; - providing the playlist to the client device, which then selects chunks to download based on the playlist and available resources.