Videoconferencing Downspeeding via Rate Difference Thresholds
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Solution Overview
Problem
Existing video conferencing systems face issues with network congestion, leading to poor quality of service due to high bitrates and limited network resources, with current congestion control algorithms being sensitive to network jitter and incorrectly initiating downspeeding, thereby reducing video quality unnecessarily.
Innovation Solution
A method and system for accurate and timely downspeeding of media streams by mapping packet identifiers and timestamps, calculating transmission and received rates, and initiating downspeeding based on specific thresholds, while also measuring packet recovery success rates to ensure optimal quality adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high bitrate media streams are transmitted to maintain video quality, then video quality is improved, but network congestion occurs leading to packet loss and service degradation
Solution Approach 1:
The system dynamically adjusts the media stream bitrate based on real-time network conditions. The sender device monitors packet transmission rates and receives feedback about packet loss and network status, then adaptively changes the encoding bitrate to match current network capacity, resolving the contradiction between maintaining high video quality and avoiding network congestion.
Solution Approach 2:
The patent implements a feedback mechanism where the receiver device sends status messages back to the sender device containing information about packet loss, transmission rate, and network conditions. This feedback loop enables the sender to adjust the media stream bitrate in response to actual network performance, preventing congestion while maintaining optimal video quality.
2Measurement precision
If congestion control algorithms are made sensitive to detect congestion early, then network congestion is detected earlier, but the algorithms become overly sensitive to network jitter and incorrectly initiate downspeeding
Solution Approach 1:
The system monitors multiple parameters simultaneously including packet transmission rate, packet loss rate, and feedback messages from the receiver. By analyzing changes in these parameters over time and comparing them against threshold values, the system can distinguish between temporary network jitter and sustained congestion, making more reliable downspeeding decisions while maintaining early congestion detection capability.
3Reliability
If downspeeding is initiated frequently to prevent congestion, then network congestion is avoided, but video quality degrades unnecessarily during normal network conditions
Solution Approach 1:
The system applies downspeeding only partially and only when necessary. By monitoring multiple parameters and comparing against threshold values, the system initiates downspeeding only when congestion is actually detected, rather than applying it frequently as a preventive measure. This ensures video quality is maintained at the highest possible level while still preventing congestion when it occurs.
Data Source
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AI summary
System and method of downspeeding a media stream transmitted over a communication link from a sender device to a receiving device. The method comprising mapping for each packet in the media stream a packet identifier, a transmission timestamp and a packet size; transmitting for each packet received at the receiving device a feedback message to the sender device, the feedback message comprising the packet identifier and an arrival timestamp; determining a transmission rate for a first sliding window of N transmitted packets by dividing a packet size sum of the N transmitted packets with a time difference between a transmission time stamp of the last of the N transmitted packets and a transmission time stamp of the first of the N transmitted packets; determining a received rate for the first sliding winding of the N transmitted packets by dividing the packet size sum of the N transmitted packets with a time difference between the arrival time stamp of the last of the N transmitted packets and the arrival time stamp of the first of the N transmitted packets; and initiating downspeeding of the media stream when for the first sliding window of the N transmitted packets the difference between the transmission rate and the received rate divided by the transmission rate is above a first downspeeding threshold.