Video Frame Identification in Obfuscated Streams via NAL Pattern Detection
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Solution Overview
Problem
Existing computing devices and media players lack the ability to efficiently identify video frames in obfuscated video streams without full deobfuscation, which decreases system efficiency and increases processing time.
Innovation Solution
A method and system that analyze transport stream packets to identify network abstraction layer (NAL) units without full decoding or decryption, allowing for the detection of video frames by recognizing a predetermined pattern indicative of NAL units, enabling frame identification without deobfuscation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full deobfuscation is performed to identify video frames, then video frame identification accuracy is improved, but processing time and computational resources increase
Solution Approach 1:
The patent extracts only the essential identification information (NAL unit headers, frame type indicators) from the obfuscated video stream without performing full deobfuscation. By taking out only the necessary metadata portions that contain frame identification patterns, the system achieves accurate frame identification while avoiding the time-consuming full decoding process.
Solution Approach 2:
The patent performs preliminary scanning of the video stream to identify NAL unit boundaries and frame types before full deobfuscation. By detecting the position and type of each video frame in advance through pattern matching on obfuscated data, the system prepares frame identification information beforehand, enabling efficient subsequent processing without repeated full decoding.
2Ease of operation
If full deobfuscation is performed to access video frame data, then data accessibility is improved, but security is compromised
Solution Approach 1:
The patent extracts only the minimal necessary information (frame positions, frame types) from the obfuscated stream without retrieving the actual video content. By taking out only the structural metadata and leaving the encrypted payload intact, the system enables frame-level accessibility for processing while maintaining security by never fully decrypting the video data.
Solution Approach 2:
The patent introduces an intermediary layer that operates on the obfuscated stream to identify frame boundaries and types without requiring full decryption. This intermediary processing layer acts as a mediator between the encrypted data and the processing requirements, enabling frame identification while keeping the actual video content secured through encryption.
3Productivity
If video frames are identified in obfuscated streams without full decoding, then processing efficiency is improved, but identification capability deteriorates
Solution Approach 1:
The patent changes the approach from attempting to decode the entire video stream to analyzing specific parameters (byte patterns, NAL unit headers, frame type indicators) that remain identifiable in the obfuscated state. By focusing on these invariant parameters that survive the obfuscation process, the system achieves both high processing efficiency and accurate frame identification capability.
Data Source
AI summary
A method and video decoder system using the method are provided for identifying video frames in an encoded or encrypted video stream without performing decoding or decryption. The method includes: receiving a video data stream comprised of a plurality of transport stream (TS) packets; detecting a first video frame in the video data stream, wherein detection of the first video frame includes registering a last checked position at the start of the video data stream, examining bytes in a next TS packet to identify a predetermined pattern indicating a network abstraction layer (NAL) unit, repeating the examining step until two TS packets have been identified that include an NAL unit, wherein the last checked position is updated after each examining step, and identifying a video frame based on a position of the NAL unit identified in the two TS packets; and repeating the detecting step for a plurality of additional video frames in the video data stream.