Implicit Quantization Control for Constant Bit Rate Video
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Solution Overview
Problem
Conventional video compression codecs struggle to maintain constant bit rate control, especially in real-time, bandwidth-limited applications, due to inefficiencies in carrying explicit quantization change information, which leads to increased bandwidth and storage costs.
Innovation Solution
A system and method for implicitly controlling quantization values in video compression by tracking and managing quantization-related parameters at a macroblock level, using a decoder and encoder management component to adjust quantization values based on a first and second subset of parameters, without explicitly carrying quantization change information in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit quantization change information is carried in the bitstream to achieve constant bit rate control, then bit rate control precision is improved, but bandwidth usage increases
Solution Approach 1:
The patent extracts the quantization change information from the bitstream by using implicit signaling. Instead of carrying explicit quantization values in the bitstream, the encoder and decoder independently determine quantization values based on tracked parameters such as buffer status and video content characteristics. This removes the overhead of transmitting quantization information while maintaining constant bit rate control capability.
Solution Approach 2:
The system employs self-service mechanisms where both encoder and decoder maintain internal state information and independently compute quantization values. The encoder tracks buffer occupancy and video complexity, while the decoder mirrors this tracking, allowing both sides to autonomously determine appropriate quantization values without requiring explicit communication of these parameters in the bitstream.
2Measurement precision
If quantization values are controlled at macroblock level to achieve constant bit rate, then bit rate control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the video stream into macroblocks and applies independent quantization control at each macroblock level. By dividing the video content into manageable units and tracking parameters separately for each segment, the system achieves fine-grained bit rate control without requiring complex global optimization algorithms. This segmentation approach allows localized adjustments to quantization values based on local buffer status and content characteristics.
3Reliability
If more bits are used to transmit quantization change information, then constant bit rate control is improved, but storage cost increases
Solution Approach 1:
The patent extracts and eliminates the need to store and transmit explicit quantization change information in the bitstream. By using implicit quantization control where the decoder independently determines quantization values based on tracked parameters, the system removes the storage overhead associated with storing quantization information while maintaining reliable constant bit rate control.
Data Source
AI summary
Techniques for controlling constant bit rate for a coded video bitstream using implicitly derived quantization values during coding are presented. A decoder component and an encoder component independently track a first subset of quantization-related parameters in relation to coding video frames. The encoder component encodes a macroblock of a video frame using a quantization value based on the first subset of coding parameters and a second subset of coding parameters. The decoder component calculates the quantization value for the macroblock based on the first subset and second subset of quantization-related parameters, the second subset received in a header with the bitstream. The decoder component uses calculated quantization values to adjust quantization levels in relation to decoding macroblocks of a frame to facilitate maintaining constant bit rate control for the bitstream. The second subset of quantization-related parameters includes parameter information other than explicit quantization change information.