VoIP MOS Calculation via Packet Payload Size Distribution
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Solution Overview
Problem
Existing methods for determining mean opinion scores (MOS) for variable bit rate (VBR) audio streams in VoIP networks are inadequate, as they fail to accurately account for dynamic bit rate changes and packet payload size variations, which affect perceived audio quality.
Innovation Solution
A method that monitors communications over VoIP networks, detects variations in packet payload sizes, calculates bit rates for different portions of the communication, and generates an overall MOS by calculating and weighting MOS scores based on the distribution of packet payload sizes, using techniques such as packet-time analysis and payload size distribution mapping to determine bit rates and MOS values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If VBR codecs are used to dynamically adjust bit rate according to network conditions and audio complexity, then bandwidth efficiency and adaptability are improved, but measurement precision of audio quality deteriorates because existing MOS determination methods cannot accurately account for dynamic bit rate changes
Solution Approach 1:
The audio stream is divided into multiple segments based on packet payload size variations. Each segment is analyzed separately to determine its specific bit rate, and MOS scores are calculated for each segment individually. This segmentation allows the system to capture dynamic bit rate changes throughout the communication, resolving the measurement precision issue while maintaining the bandwidth efficiency benefits of VBR codecs.
Solution Approach 2:
The system dynamically changes the bit rate parameter based on packet payload size observations. By monitoring payload size variations and mapping them to corresponding bit rates, the system adapts the MOS calculation to match the actual dynamic bit rate conditions of VBR audio streams, thereby improving measurement precision without sacrificing adaptability.
2Measurement precision
If packet payload size variations are monitored to determine bit rates, then MOS calculation accuracy is improved, but device complexity increases due to the need to track and analyze multiple packet parameters
Solution Approach 1:
The system extracts only the essential information needed for MOS calculation from the packet stream - specifically packet payload sizes. By focusing on this single key parameter and using it to infer bit rate changes, the system achieves accurate MOS calculation without the need to monitor and analyze all packet parameters, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
Instead of directly analyzing complex audio content to determine quality, the system creates a simplified copy or representation of quality information through packet payload size measurements. This indirect measurement approach captures the essential quality variations caused by VBR encoding without requiring complex audio analysis, reducing system complexity while preserving MOS calculation accuracy.
Data Source
AI summary
Systems and methods for determining mean opinion scores (MOS) for variable bit rate (VBR) audio streams transmitted over VoIP networks are described. In an embodiment, a method may include monitoring a communication over a network and detecting portions of the communication including packets having a different packet payload sizes. The method may also include deriving bit rates corresponding to those portions. The method may then include calculating MOS values for each portion based on the derived bit rates, and calculating an overall MOS value for the communication based upon each individual MOS value averaged according to a distribution of packets having the different packet payload sizes.