Sub-picture Hierarchical QP Coding for Video Latency
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Solution Overview
Problem
Conventional hierarchical prediction structures in video coding face challenges with large variations in frame sizes and bit rates, leading to increased latency and instability in rate control mechanisms, especially in real-time video transmission applications.
Innovation Solution
The method involves dividing video frames into predetermined regions and assigning unique quantization parameters to each region, using a cyclic pattern of quantization parameters across frames to maintain a constant average bit rate and reduce latency, while allowing for flexible prediction structures that do not always reference the immediately preceding frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hierarchical prediction structures are used to improve temporal scalability, then video quality is improved, but latency increases and rate control stability deteriorates
Solution Approach 1:
The video frame is divided into multiple regions with different quantization parameters, allowing different parts of the frame to be encoded with different quality levels. This segmentation enables selective allocation of bits to important regions while reducing overall complexity and latency.
Solution Approach 2:
Different regions within the same frame are assigned different quantization parameters, creating local quality variations. Important regions (e.g., motion-active areas) receive higher quality encoding while less important regions use lower quality, maintaining overall video quality while reducing total bit rate and latency.
2Manufacturing precision
If hierarchical prediction structures are used to improve temporal scalability, then video quality is improved, but rate control stability deteriorates
Solution Approach 1:
The patent applies cyclic patterns of quantization parameters across frames, creating a periodic structure in the bit rate allocation. This periodicity helps stabilize rate control by predictable bit rate variations rather than random fluctuations, while still maintaining temporal scalability through the hierarchical prediction structure.
Solution Approach 2:
The patent dynamically changes quantization parameters across different regions and frames to control bit rate while maintaining video quality. By adjusting QP values in a structured manner, the system achieves both quality improvement and rate control stability through controlled parameter variation.
3Manufacturing precision
If variable quantization parameters are used to improve video quality, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The frame is divided into a predetermined number of regions with assigned quantization parameters. This segmentation provides a structured approach to variable QP coding, reducing the complexity of determining QP values for each block while still achieving quality improvements through regional differentiation.
Solution Approach 2:
Instead of applying complex variable QP to every block, the patent applies QP variation at a coarser regional level. This partial action approach achieves most of the quality benefit with significantly reduced complexity compared to block-level QP variation.
Data Source
AI summary
A method including: dividing a first video frame into a predetermined plurality of regions; assigning a quantization parameter to each of the predetermined plurality of regions in accordance with a first predetermined pattern of quantization parameters, the quantization parameters not being all the same; dividing video frames, subsequent to the first video frame, into the predetermined plurality of regions; and assigning a quantization parameter to each of the predetermined plurality of regions in the video frames subsequent to the first video frame, in accordance with another predetermined pattern, different from the first predetermined pattern.