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

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
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