Adaptive Intra Refresh Rate Selection in Video Encoders
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video communication systems over Internet or wireless networks face severe video quality degradation due to packet loss, which is exacerbated by predictive video coders, and current error resilience mechanisms like intra-frame coding lead to inefficient prediction and sub-optimal refresh rates, resulting in non-uniform spatial quality.
Innovation Solution
A system and method for adaptive intra refresh rate setting in video encoders, which uses spatiotemporal content, operating bit-rate, and channel adaptive intra refresh rate selection to minimize end-to-end distortion by computing source coding and channel induced distortion values at multiple intra refresh rates, allowing for optimal frame-level optimization and error resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic intra-frame coding is used for error resilience, then error propagation is controlled, but coding efficiency drops due to inefficient prediction
Solution Approach 1:
The patent implements dynamic intra-refresh rate adjustment based on frame-level distortion analysis. The system computes expected distortion for multiple candidate refresh rates (e.g., 1/4, 1/8, 1/16, 1/32 frames) and selects the optimal rate that minimizes total distortion while adapting to varying channel conditions and content characteristics, rather than using fixed periodic intra-frame coding
Solution Approach 2:
The system changes the intra-refresh rate parameter dynamically based on computed distortion metrics. By analyzing frame-level expected distortion and selecting from multiple candidate refresh rates, the system optimizes the balance between error resilience (higher refresh rates) and coding efficiency (lower refresh rates) for different video frames and channel conditions
2Manufacturing precision
If frame-level optimization is performed with multiple candidate refresh rates, then end-to-end distortion is minimized, but computational complexity increases
Solution Approach 1:
The system computes expected distortion for a limited set of discrete candidate refresh rates (typically 4-5 rates: 1/4, 1/8, 1/16, 1/32 frames) rather than evaluating all possible refresh rates continuously. This partial evaluation approach achieves near-optimal distortion minimization while significantly reducing computational complexity compared to exhaustive search
Solution Approach 2:
The system performs preliminary frame-level distortion analysis and candidate refresh rate evaluation before final encoding. By pre-computing expected distortion metrics and selecting the optimal refresh rate in advance, the system avoids complex real-time adjustments during encoding while still achieving optimized distortion performance
3Productivity
If MB-level rate control is used, then bit-rate allocation is optimized, but spatial quality uniformity deteriorates due to skewing over the frame
Solution Approach 1:
The patent implements frame-level optimization that selects a uniform intra-refresh rate applied across the entire frame, rather than applying different rate control parameters to different macroblocks. This approach maintains spatial quality uniformity while still achieving bit-rate efficiency through optimal refresh rate selection based on overall frame distortion characteristics
Data Source
AI summary
A system and method for adaptive intra refresh rate setting for each video frame in a video encoder is disclosed. In one embodiment, a video encoding method includes computing channel induced distortion values at multiple intra refresh rates for a coded video frame as a function of channel loss and spatiotemporal content, computing source coding distortion values at the multiple intra refresh rates for the coded video frame as a function of the spatiotemporal content and an operating bit-rate, selecting an intra refresh rate value for one or more video frames subsequent to the encoded video frame as a function of the sum of the corresponding computed channel induced distortion values and the source coding distortion values, and encoding the one or more video frames using the selected intra refresh rate value.