LINE Call: 8 year journey to the top level quality

LINE Call: 8 year journey to the top level quality

Dongwon Lee
LINE Plus Dev 3 Software Engineer
https://linedevday.linecorp.com/jp/2019/sessions/F2-5

Be4518b119b8eb017625e0ead20f8fe7?s=128

LINE DevDay 2019

November 21, 2019
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Transcript

  1. 2019 DevDay LINE Call: 8 Year Journey to the Top

    Level Quality > Dongwon Lee > LINE Plus Dev 3 Software Engineer
  2. Agenda > What Defines the Best Call Quality? > How

    to Assess Call Quality > Global Quality Monitoring System
  3. The Best Call Quality

  4. Tele-communication

  5. The New Paradigm Communication

  6. The New Paradigm Communication Connecting to Each Other

  7. Close Distance: 45 cm Communication Distance Social Distance: 1.2 m

    ~ 3.6 m Personal Distance: 45 cm ~ 1.2 m [openclipart.org] 1 m
  8. Assessment of Quality

  9. Reference Signal Digitalize Compress Degraded Signal Audio Converter Packet Network

    Time Stamp IP Address Add Address UDP header #5 #4 #3 #2 #1 IP Receiver Time Sequence #5 #3 #4 #2 #1 #5 #4 #3 #2 #1 Voice Over Internet
  10. MOS: Mean Opinion Score 5 EXCELLENT 4 GOOD 3 FAIR

    2 POOR 1 BAD
  11. Listening test Original Voice 1 Voice 2 5 EXCELLENT 4

    GOOD 3 FAIR 2 POOR 1 BAD
  12. Objective measurements POLQA v3 Perceptual Objective Listening Quality Assessment PAMS

    Perceptual Analysis Measurement System PESQ Perceptual Evaluation of Speech Quality PSQM Perceptual Speech Quality Measure 1997 2001 2011 1998 2018 POLQA Full Band
  13. ? Call quality over the world? 200+ Countries Expedition Team

  14. Expedition Team

  15. Global Monitoring System

  16. > To measure the call quality of not only LINE

    but also competing apps > Easy to monitor and compare the measured metrics > To measure the objective metrics obtained by the expedition team Global Quality Monitoring System
  17. Global Quality Monitoring System

  18. None
  19. Analysis - Good Voice

  20. Analysis - Bad Voice

  21. Encoding Packetization Input Signal Network Depacketization Decoding Reference Signal Output

    Signal Full Reference (FR) Degraded Signal No Reference (NR) Media Stream Media Stream Video Quality Measurement
  22. Nature of Video Code: Blockiness [Original] [Blocky]

  23. VMAF PSNR MS-SSIM PSNR-HVS FR Methods

  24. [Practical Evaluation of VMAF Perceptual Video Quality for WebRTC Applications,

    Boni García,, Luis López-Fernández, 31,Jul,2019,MDPI electrinics] Performance Comparison
  25. [Practical Evaluation of VMAF Perceptual Video Quality for WebRTC Applications,

    Boni García,, Luis López-Fernández, 31,Jul,2019,MDPI electrinics] Comparison with Human Score
  26. Video Data Acquisition [Sender] [Receiver] 1 2 3 1 3

  27. 3 1 4 2 1 4 3 2 Video Data

    Acquisition [Sender] [Receiver] FR Method
  28. Result of Video Assessment VMAF Freezing Skipness https://www.youtube.com/watch?v=6ArXfcKeZWY

  29. Subtitle Title 120pt Bad Quality Video

  30. Auditory System Pinna Ear Canal Cochlea

  31. Measured Like the Human Ear HATS: Head And Torso Simulator

  32. Customer Satisfaction Survey 53% 33%

  33. Thank you