Video Encoder Bit Rate Controller Adaptive Quantization
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Solution Overview
Problem
Conventional methods for controlling encoding rates in MPEG-2 video encoders, particularly the variable bit-rate (VBR) control method, face challenges in defining the exact rate-distortion relationship and adapting quantizer scales effectively to varying picture features, leading to suboptimal picture quality improvements.
Innovation Solution
A real-time VBR control method that calculates the target number of bits-per-picture based on previous encoding results, sets quantizer scales adaptively to current picture features without defining a rate-distortion relationship, and uses a limited number of bits, ensuring effective bit allocation and quality improvement without additional bit usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional VBR control method is used to allocate more bits to motion picture video data, then picture quality is improved, but the complexity of defining exact rate-distortion relationship and adapting quantizer scales increases
Solution Approach 1:
The patent extracts and eliminates the complex rate-distortion relationship definition from the VBR control process. Instead of defining exact rate-distortion relationships and adapting quantizer scales based on picture features, the invention uses a simplified approach that allocates bits based on previous encoding results and buffer balance values, thereby reducing computational complexity while maintaining picture quality improvement
Solution Approach 2:
The patent changes the control parameter from complex rate-distortion optimization to a simplified bit allocation based on previous encoding results and buffer balance. The quantizer scale is adjusted adaptively based on current picture features without requiring complex rate-distortion modeling, thus reducing system complexity while achieving quality improvement
2Productivity
If conventional VBR control method forces limited bit allocation, then encoding rate is controlled, but picture quality improvement is suboptimal when picture features vary
Solution Approach 1:
The patent introduces dynamic bit allocation that adapts to current picture features without forcing a fixed limited bit allocation. The target number of bits-per-picture is calculated based on previous encoding results and buffer balance values, allowing flexible adjustment according to actual encoding needs and picture characteristics, thereby optimizing both encoding rate control and picture quality
Solution Approach 2:
The patent implements feedback-based bit allocation where the target number of bits-per-picture is calculated using previous encoding results and buffer balance values. This feedback mechanism allows the system to adjust bit allocation dynamically based on actual encoding performance and picture features, achieving optimal picture quality improvement without suboptimal forced limitations
3Manufacturing precision
If quantizer scale is set adaptively to current picture features, then picture quality is enhanced, but additional bits are required for variation of quantizer scale
Solution Approach 1:
The patent enables the quantizer scale to adjust adaptively to current picture features using the available bit budget without requiring additional bits. The system self-regulates by calculating the target number of bits-per-picture based on previous encoding results and buffer balance, then distributing bits efficiently across macroblock rows to achieve quality improvement within the constrained budget
Data Source
AI summary
A method of controlling an encoding (bit) rate and a method of transmitting video data, and an encoding (bit) rate controller for a video encoder and a video data transmission system employing the methods, wherein the number of bits is allocated to a current picture on the basis of previous encoding results without defining a relation between an encoding rate and the distortion, the limited number of bits is not forced when features of the current picture are different from those of the previous pictures, and a quantizer scale is set adaptively to various features of the current picture without using an additional number of bits corresponding to variation of the quantizer scale, so that it is possible to improve the picture quality of video data to be displayed on a monitor by using such real time variable bit-rate control.