Encrypted Video Stream Image Extraction
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Solution Overview
Problem
The existing technologies for video content distribution face challenges in enabling fast forwarding and thumbnail generation within encrypted video streams due to bandwidth limitations and the inability of distribution servers to access and decrypt the video content, making it difficult to extract relevant information from encrypted video streams.
Innovation Solution
A method for selective extraction of images from encrypted video streams by terminals, using low-resolution versions of the stream to require minimal bandwidth, allowing for fast forwarding and thumbnail generation without decrypting the content, by storing video streams in multiple resolutions and allowing terminals to request and decrypt only necessary parts of the stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the video stream is downloaded at a faster speed to enable fast-forwarding, then the playback speed is improved, but the bandwidth consumption increases significantly
Solution Approach 1:
The video stream is divided into encrypted blocks, and only specific blocks containing I-frames are extracted and downloaded. This segmentation allows selective retrieval of essential frames for fast-forwarding without downloading the entire video stream, thus enabling faster playback while reducing bandwidth consumption.
Solution Approach 2:
The patent extracts only the necessary I-frames from the encrypted video stream blocks. By taking out only these critical self-contained frames and excluding other frame types (P-frames, B-frames), the system achieves fast-forwarding capability with minimal bandwidth usage, as these extracted frames alone are sufficient for video playback.
2Ease of operation
If the distribution server decrypts the video stream to extract representative frames, then the navigation capability is improved, but the security is worsened
Solution Approach 1:
The terminal device performs the decryption operation itself using cryptographic keys obtained from a DRM server, rather than requiring the distribution server to decrypt the video stream. This self-service approach allows the terminal to extract representative frames for navigation while maintaining security, as the distribution server never needs to access the encrypted content.
3Loss of energy
If only a portion of the video stream is transmitted to reduce bandwidth, then the bandwidth consumption is reduced, but the decompression capability is worsened
Solution Approach 1:
The patent applies different quality requirements to different parts of the video stream by selecting only I-frames for extraction. These I-frames are transmitted in their entirety with sufficient quality to be self-contained and decompressible, while other frame types are excluded. This local quality approach ensures that the transmitted portion has the necessary decompression capability without wasting bandwidth on redundant data.
4Productivity
If representative frames are extracted from encrypted video streams, then the navigation efficiency is improved, but the complexity of the system is worsened
Solution Approach 1:
The video stream is pre-divided into encrypted blocks during encoding, with I-frames positioned at specific intervals. This preliminary structuring allows the terminal to efficiently locate and extract representative frames without complex real-time analysis, improving navigation efficiency while keeping the system relatively simple.
Data Source
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AI summary
A method for selectively extracting, by a terminal, at least one image to be extracted from an encrypted video stream, several encrypted versions of said encrypted video stream being stored on a server incapable of decrypting said encrypted versions of the video stream, said several encrypted versions comprising at least one low-resolution version and one high-resolution version, each encrypted version of said encrypted video stream being divided into encrypted blocks, each encrypted block containing several encrypted images, said method comprising: - selecting an encrypted block from the low-resolution encrypted version of the encrypted video stream, said encrypted block containing an image to be extracted; - selecting a subset of said encrypted block containing said image to be extracted; - transmitting said subset to the terminal; - decrypting said subset by the terminal;- extraction, by the terminal, of said image to be extracted from said decrypted subset.;