Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
LINE Call: 8 year journey to the top level quality
Search
LINE DevDay 2019
November 21, 2019
Technology
0
350
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
LINE DevDay 2019
November 21, 2019
Tweet
Share
More Decks by LINE DevDay 2019
See All by LINE DevDay 2019
What is the engineering organization that LINE DevRel is aiming for
line_devday2019
3
2.6k
The IoT technology inside LINE DEVELOPER DAY 2019
line_devday2019
6
1.2k
How to reduce Android app launch time by scoping your dependencies using Koin DI
line_devday2019
3
900
Efficient integrating data from multiple data providers
line_devday2019
0
550
Now supporting Dark Mode on LINE messenger
line_devday2019
0
2.2k
LIFF v2, the latest Webview SDK lets you leverage LINE
line_devday2019
0
1.8k
Modern Web Testing with Cypress.io
line_devday2019
0
710
Speed up iOS Development with LLDB Code Injection and Framework Live Preview
line_devday2019
1
450
Faster iOS Builds with Bazel
line_devday2019
0
1.6k
Other Decks in Technology
See All in Technology
Postman MCP 関連機能アップデート / Postman MCP feature updates
yokawasa
0
140
夢の印税生活 / Life on Royalties
tmtms
0
280
どこで動かすか、誰が動かすか 〜 kintoneのインフラ基盤刷新と運用体制のシフト 〜
ueokande
0
180
GCASアップデート(202506-202508)
techniczna
0
250
Goss: Faiss向けの新しい本番環境対応 Goバインディング #coefl_go_jp
bengo4com
0
1.4k
Figma + Storybook + PlaywrightのMCPを使ったフロントエンド開発
yug1224
3
150
小さなチーム 大きな仕事 - 個人開発でAIをフル活用する
himaratsu
0
120
「守る」から「進化させる」セキュリティへ ~AWS re:Inforce 2025参加報告~ / AWS re:Inforce 2025 Participation Report
yuj1osm
1
110
Product Management Conference -AI時代に進化するPdM-
kojima111
0
220
実践アプリケーション設計 ③ドメイン駆動設計
recruitengineers
PRO
1
150
[CVPR2025論文読み会] Linguistics-aware Masked Image Modelingfor Self-supervised Scene Text Recognition
s_aiueo32
0
210
事業価値と Engineering
recruitengineers
PRO
1
190
Featured
See All Featured
The Myth of the Modular Monolith - Day 2 Keynote - Rails World 2024
eileencodes
26
3k
Typedesign – Prime Four
hannesfritz
42
2.8k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
367
26k
Exploring the Power of Turbo Streams & Action Cable | RailsConf2023
kevinliebholz
34
6k
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
161
15k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
15
1.6k
What's in a price? How to price your products and services
michaelherold
246
12k
Optimizing for Happiness
mojombo
379
70k
jQuery: Nuts, Bolts and Bling
dougneiner
64
7.9k
Build your cross-platform service in a week with App Engine
jlugia
231
18k
A Tale of Four Properties
chriscoyier
160
23k
XXLCSS - How to scale CSS and keep your sanity
sugarenia
248
1.3M
Transcript
2019 DevDay LINE Call: 8 Year Journey to the Top
Level Quality > Dongwon Lee > LINE Plus Dev 3 Software Engineer
Agenda > What Defines the Best Call Quality? > How
to Assess Call Quality > Global Quality Monitoring System
The Best Call Quality
Tele-communication
The New Paradigm Communication
The New Paradigm Communication Connecting to Each Other
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
Assessment of Quality
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
MOS: Mean Opinion Score 5 EXCELLENT 4 GOOD 3 FAIR
2 POOR 1 BAD
Listening test Original Voice 1 Voice 2 5 EXCELLENT 4
GOOD 3 FAIR 2 POOR 1 BAD
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
? Call quality over the world? 200+ Countries Expedition Team
Expedition Team
Global Monitoring System
> 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
Global Quality Monitoring System
None
Analysis - Good Voice
Analysis - Bad Voice
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
Nature of Video Code: Blockiness [Original] [Blocky]
VMAF PSNR MS-SSIM PSNR-HVS FR Methods
[Practical Evaluation of VMAF Perceptual Video Quality for WebRTC Applications,
Boni García,, Luis López-Fernández, 31,Jul,2019,MDPI electrinics] Performance Comparison
[Practical Evaluation of VMAF Perceptual Video Quality for WebRTC Applications,
Boni García,, Luis López-Fernández, 31,Jul,2019,MDPI electrinics] Comparison with Human Score
Video Data Acquisition [Sender] [Receiver] 1 2 3 1 3
3 1 4 2 1 4 3 2 Video Data
Acquisition [Sender] [Receiver] FR Method
Result of Video Assessment VMAF Freezing Skipness https://www.youtube.com/watch?v=6ArXfcKeZWY
Subtitle Title 120pt Bad Quality Video
Auditory System Pinna Ear Canal Cochlea
Measured Like the Human Ear HATS: Head And Torso Simulator
Customer Satisfaction Survey 53% 33%
Thank you