Video Encoder Rate Control via Priority-Based Sub-GOP Segmentation
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Solution Overview
Problem
Existing video encoding solutions are complex and inefficient in controlling compression rates to achieve a desired bitrate while maintaining high video quality, particularly in applications with limited transmission interfaces.
Innovation Solution
A method and system for video encoding that uses a rate control block to adjust the quantization parameter based on previously encoded frames, calculating ratios and adjusting the sliding window size to maintain a target bitrate, thereby controlling the bitrate efficiently and smoothly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing rate control methods are used to control compression rate, then bitrate can be adjusted, but the control becomes complex and slow
Solution Approach 1:
The patent segments the video stream into groups of pictures (GOPs) and further divides them into sub-GOPs with different priority levels. High-priority sub-GOPs are encoded first with higher quality, while low-priority sub-GOPs use lower quality encoding. This segmentation allows independent control of different video segments, simplifying rate control while maintaining efficiency.
Solution Approach 2:
The patent applies local quality by assigning different quantization parameters to different sub-GOPs based on their priority. High-priority sub-GOPs receive lower quantization parameters (higher quality), while low-priority sub-GOPs receive higher quantization parameters (lower quality). This localized quality adjustment enables efficient bitrate control without uniformly degrading entire video sequences.
2Quantity of substance
If compression rate is increased to reduce bitrate, then transmission bandwidth is reduced, but video quality deteriorates
Solution Approach 1:
The patent implements local quality by differentiating encoding quality across priority levels. High-priority sub-GOPs are encoded with high quality (low quantization parameter) to preserve important visual information, while low-priority sub-GOPs use lower quality (high quantization parameter) to reduce overall bitrate. This selective quality approach maintains acceptable video quality while achieving target bitrate.
Solution Approach 2:
The patent applies partial action by selectively applying high-quality encoding only to high-priority sub-GOPs rather than uniformly encoding all sub-GOPs at high quality. This partial application of high-quality encoding reduces overall bitrate while maintaining acceptable quality for the most important video content.
3Productivity
If uniform quality encoding is applied to all video frames, then video quality consistency is maintained, but bitrate control becomes inefficient
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through priority-based sub-GOP encoding. Instead of uniform quality across all frames, the system applies different quality levels to different sub-GOPs based on their priority classification. This allows efficient bitrate control while maintaining quality consistency within each priority group.
Solution Approach 2:
The patent introduces dynamics by making the encoding quality adaptive rather than static. The quantization parameter dynamically adjusts based on the priority level of each sub-GOP and the current bitrate conditions. This dynamic approach enables efficient bitrate control while maintaining perceived quality consistency through priority-based quality management.
Data Source
Figure 1~3
AI summary
The invention concerns a method of video encoding comprising: determining a first ratio (IPRATIO) based on previously encoded picture frames of a video sequence comprising one or more intra-coded pictures (I) and one or more predicted pictures (P), the first ratio (IPRATIO) being calculated based on the ratio between the size of one or more previously encoded intra-coded pictures and the size of one or more previously encoded predicted pictures; and determining a quantization parameter (QP) to be applied to a frame to be encoded based on the first ratio (IPRATIO).