Frame Rate Control Using Threshold-Based Picture Dropping
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Solution Overview
Problem
In video communication, fluctuating input timing of video frames from devices like Web cameras can lead to increased computational complexity and bitstream information, causing unnecessary picture dropping or insufficient dropping, resulting in video quality degradation due to mismatched frame rates between input and encoding capabilities.
Innovation Solution
A frame rate control method that determines whether to drop input video frames based on a predetermined threshold of past frames within a unit time, rather than relying on the fluctuating input frame rate, to maintain computational complexity and bitstream information within a given range, preventing instantaneous increases in encoding workload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If picture dropping is performed based on measured input frame rate, then frame rate conversion is achieved, but video quality degrades due to fluctuating frame rates causing unnecessary or insufficient picture dropping
Solution Approach 1:
The patent applies preliminary action by pre-calculating the maximum number of pictures that can be input within a reference time period before actual encoding occurs. This allows the system to proactively determine picture dropping decisions based on predetermined thresholds rather than reacting to fluctuating frame rates, thereby maintaining stable video quality while achieving efficient frame rate conversion.
2Reliability
If all input video frames are encoded, then video quality is maintained, but computational complexity and bitstream information increase instantaneously
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the picture dropping decision based on the calculated maximum picture count threshold. When the number of input pictures exceeds this threshold, pictures are dropped to control computational complexity and bitstream information. This parameter-based control mechanism balances video quality maintenance with encoding resource management.
3Speed
If picture dropping is performed to reduce computational load, then encoding speed improves, but video quality degrades due to insufficient picture retention
Solution Approach 1:
The patent applies feedback by continuously monitoring the number of input pictures against the pre-calculated maximum threshold and adjusting picture dropping decisions accordingly. This feedback mechanism ensures that pictures are dropped only when necessary to maintain encoding speed, while retaining sufficient pictures to preserve video quality, creating a balanced control system.
Data Source
AI summary
An object is to suppress an instantaneous increase in the computational complexity of an encoder and an information amount of an encoding result without increasing a delay even when input timing of input video is not constant and fluctuates. A frame rate control method for adjusting a frame rate of input video to a frame rate at which an encoder is able to perform encoding includes: a step of determining whether the number of pictures input in the past within a predetermined time from a time when a determination target picture of dropping is input exceeds a predetermined threshold value; and a step of discarding the determination target picture if the number of pictures exceeds the threshold value and designating the determination target picture as an encoding target if the number of pictures does not exceed the threshold value.