Picture Encoding Rate Control for Low Delay
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Solution Overview
Problem
Existing moving picture compression technologies face challenges in minimizing buffering delay, particularly in consumer-use systems with limited transmission bandwidth, as bitrate fluctuation leads to significant transmission delays.
Innovation Solution
The solution involves a picture encoding device with a quantization step, entropy encoding, and a rate control mechanism that adjusts the quantization parameter based on predicted bit allocation to ensure uniform bit distribution across sections, and a second rate control unit that manages carryover bits to limit buffering delay while maintaining picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffers are inserted at encoder and decoder sides to smooth bitrate fluctuation, then transmission reliability is improved, but buffering delay doubles
Solution Approach 1:
The patent divides the picture into multiple sections and performs rate control on each section independently. This segmentation allows for finer-grained bitrate management, smoothing fluctuations at a granular level without requiring large buffers, thus reducing buffering delay while maintaining transmission reliability.
Solution Approach 2:
The patent dynamically adjusts the quantization parameter for each section based on predicted bit allocation and actual encoding results. This dynamic adjustment enables real-time bitrate control that adapts to content complexity variations, smoothing bitrate fluctuation without fixed buffer requirements, thereby reducing buffering delay.
2Reliability
If rate control is performed on sections smaller than one picture, then bitrate fluctuation is reduced, but encoding complexity increases
Solution Approach 1:
The patent performs preliminary prediction of bit allocation for each section before actual encoding. This preliminary action allows the rate control mechanism to pre-determine appropriate quantization parameters, avoiding the need for complex iterative adjustments during encoding, thus reducing encoding complexity while maintaining bitrate uniformity.
Solution Approach 2:
The patent implements a feedback mechanism where the actual bit allocation results from encoding are compared with predicted values, and the quantization parameter is adjusted accordingly for subsequent sections. This feedback loop enables automatic adaptation to encoding variations without manual intervention, simplifying the overall encoding process while achieving consistent bitrate control.
Data Source
AI summary
A buffering delay can be reduced and moving picture encoding in low delay is performed while deterioration of picture quality is minimized.A quantization step of performing quantization of input information based on a value of a quantization parameter and decreasing an amount of information; an entropy encoding step of performing entropy encoding processing with respect to an output of the quantization step, and outputting a code generated as a result of the processing and information of a code amount generated as a result of the processing; and a rate control step of determining a value of a quantization parameter based on a result of the information of a generated code amount are provided, and the rate control step makes, for each section smaller than one picture, the value of a quantization parameter large when bit allocation in the section is expected to exceed a predetermined value, and makes the value of a quantization parameter small when the bit allocation in the section is expected to fall below the predetermined value.