Picture-Level PVR Functions in Video Compression
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Solution Overview
Problem
Conventional personal video recording functions are hindered by data dependencies and encryption in video compression standards, leading to complications in accessing video data at appropriate intervals during non-continuous playback orders, especially during fast forward and rewind operations.
Innovation Solution
The system embeds personal video recording functions at the picture level by using a controller to fetch, decrypt, and create picture tables for Group of Pictures (GOPs), allowing for flexible decoding orders during fast forward and rewind operations, and writes commands into user data to execute these functions without relying on transport packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If video data is encrypted to protect copyright and security, then security is improved, but accessing video data at appropriate intervals during non-continuous playback becomes complicated
Solution Approach 1:
The video data is divided into discrete pictures that can be independently accessed. Each picture is encrypted separately, allowing the system to decrypt and access individual pictures or groups of pictures without needing to decrypt the entire video stream, thus maintaining security while enabling random access during fast forward and rewind operations
Solution Approach 2:
The system performs preliminary decryption of pictures that will be needed for future playback operations. By anticipating which pictures will be accessed during fast forward or rewind and decrypting them in advance, the system maintains security through encryption while ensuring quick access when needed
2Productivity
If video compression standards introduce data dependencies between pictures, then compression efficiency is improved, but decoding order becomes restricted and differs from rewind and fast forward order
Solution Approach 1:
The video stream is segmented into Group of Pictures (GOP) structures with independent picture units. Each picture within a GOP can be independently decoded and displayed, allowing the system to maintain compression efficiency through inter-picture dependencies while enabling flexible decoding orders for fast forward and rewind operations by selecting and decoding specific pictures from different GOPs
Solution Approach 2:
The system introduces an intermediary picture buffer that decouples the decoding order from the display order. Pictures are decoded according to compression requirements and stored in the buffer, then retrieved and displayed in the desired order for fast forward or rewind operations, mediating between the restrictive decoding order and the flexible playback order requirements
3Measurement precision
If pictures are decoded after their data dependencies are resolved, then decoding accuracy is improved, but display delay increases during non-standard playback orders
Solution Approach 1:
The system performs preliminary decoding of pictures that will be needed for fast forward or rewind operations by analyzing the playback pattern and proactively decoding required pictures before they are actually displayed. This maintains decoding accuracy by ensuring all dependencies are resolved while minimizing display delay through advance preparation
Solution Approach 2:
The system dynamically adjusts the decoding strategy based on the current playback mode. During standard playback, pictures are decoded in sequential order according to dependencies. During fast forward or rewind, the system dynamically reorders decoding operations to prioritize pictures needed for the current playback position, balancing decoding accuracy requirements with display timing needs
Data Source
AI summary
Described herein are system(s), method(s), and apparatus for embedding personal video recorder functions at the picture level. In one embodiment, there is presented a computer readable medium for storing a data structure. The data structure comprises a picture header and at least one command following the picture header.