LINE Call: 8 year journey to the top level quality

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