Surveillance Video Encoding via Activity-Based Coding Mode Selection
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Solution Overview
Problem
Existing video coding techniques, such as MPEG and H.264, are inefficient for surveillance applications with low activity levels, as they require fixed or adaptive Group of Picture structures that result in lower compression performance due to not fully exploiting temporal correlations between frames.
Innovation Solution
A method that evaluates the activity level of video frames relative to neighboring frames, encoding using inter-coding if criteria are met without Group of Picture constraints, and intra-coding otherwise, to optimize compression based on activity levels, thereby reducing bit rate and storage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If inter-frame coding is used to exploit temporal redundancy between frames, then compression rate is improved, but the fixed Group of Picture structure prevents full exploitation of temporal correlations in low activity scenes
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed GOP structure to a dynamic coding structure where the coding mode (intra or inter) is determined adaptively based on the measured activity level of each frame. The system dynamically adjusts coding parameters according to scene activity, allowing full exploitation of temporal correlations in low-activity surveillance scenes while maintaining compression efficiency.
Solution Approach 2:
The patent changes the parameter of coding mode selection from a fixed GOP-based approach to an activity-level-based approach. By introducing activity detection as a decision parameter, the system can switch between intra-coding and inter-coding modes optimally, improving compression performance without being constrained by predetermined frame intervals.
2Ease of operation
If intra-frame coding is used to allow easy post-processing and direct image access, then ease of operation is improved, but bit rate increases compared to predictive coding
Solution Approach 1:
The patent applies local quality by using intra-coding selectively only for frames with high activity levels where temporal prediction would be inefficient, while using inter-coding for low-activity frames. This localized application of coding modes optimizes the balance between post-processing ease and bit rate, ensuring intra-coding benefits are realized only where necessary.
3Reliability
If fixed Group of Picture structures are used to provide entry points for channel changes, then reliability is improved, but compression performance decreases due to periodic intra-coded frames regardless of scene activity
Solution Approach 1:
The patent replaces the static GOP structure with a dynamic coding approach where intra-coded frames are inserted based on actual scene activity rather than fixed intervals. This dynamic adaptation maintains reliability for channel changes by ensuring intra-coded reference frames are available when needed (during activity) while avoiding unnecessary intra-frames during low-activity periods, thus improving compression performance.
Data Source
AI summary
Methods and apparatus are provided for encoding video, such as surveillance video. A video frame is encoded by evaluating a level of activity in video frame relative to one or more neighboring frames; encoding the video frame using an inter-coding technique if the evaluation satisfies one or more predefined inter-coding criteria, wherein said inter-coding technique is applied to said video frame without a Group of Picture structure having a maximum number of consecutive inter-coded frames; and encoding the video frame using an intra-coding technique if the evaluation satisfies one or more predefined intra-coding criteria. The evaluating step may comprise, for example, determining whether differences between the video frame and the one or more neighboring frames exceed a predefined threshold.