paris video tech - 1st edition: dailymotion améliorer l'expérience utilisateur grâce aux...

User Experience – Streaming Analytics

• 100 millions video views each day

• 60% desktop - 31 % mobile - 8% tablet - 1% TV

• 97% VOD - 3% live

• World Wide (France = ~ 30%)

• 69% html5 - 31% flash

Introduction : Dailymotion Facts

• Increasing user engagement => Raising revenue

• Multi dimensional : loading, engagement, rebuffering, video quality

• User experience is context sensitive • device• content

Goal : What is user experience ?

• How to implement data pipeline ?

• How to understand what is going on ?• User quality metrics• Video quality metrics• Network quality metrics

• How to improve user experience ?• Optimize delivery• Optimize player

Goal : Improving user experience

Player events Data aggregation Visualization

Data pipeline : Architecture Overview

• real-time activity

• watched > 0

• 1 month

Data visualization : Heatmap example

• More data beats better models - avoiding overfitting

• Better data beats more data - cleaning outliers

• The 80/20 rule

• P-value - measure uncertainty

Data pipeline : Basic Rules

• Choosing metrics => process not deterministic

• User engagement : Played , Watched , Watched ratio?

• Rebuffering event => waitTime > X ms ?

Data pipeline : choosing key metrics

• CDN comparison

• Routing optimization

• Country:KR

• Stream type : recorded

Data analysis : latency / CDN

• CDN comparison

• Routing optimization

• Country:KR

• Stream type : recorded

Data analysis : kbps / CDN

• seekNb

• negative correlation

• stream type : recorded

• 1 month

Data Analysis : seekNb / engagement

• buffering measure choice

• negative correlation

• stream type : recorded

• 1 month

Data analysis : buffering ratio / engagement

• rebufferingNb

• Negative Correlation

• stream type : recorded

• 1 month

Data analysis : rebufferingNb / engagement

• quality switch

• ABR algorithm

• stream type : recorded

• 1 month

Data analysis : level avg

State of ABR - stream tech comparison - VoD

rebufferingNb, percentage per tech worldwide

native 83.6%

hls.js 89.4%

flashls90.6%

State of ABR - stream tech comparison - live

rebufferingNb, percentage per tech worldwide

native 70.4%

hls.js 73.6%

flashls80.6%

introduce history parameter to bandwidth estimation in

inspired from

ABR now based on two bandwidth moving average• a fast one : adapting down quickly• a slow one : adapting up more slowly

bw estimate = min ( fast, slow)

Data-Driven Development : ABR Algorithm

uses

Are these magic numbers suitable for our use case ?

ABR magic numbers

A/B testing ABRdefine 20 traffic segments, each using a different config

enable in production …

Iteration 1 Fast average Slow average

control group 0 0

test group 1 0 1

test group 2 0 2

... 1 1

test group 18 1 9

test group 19 1 10

A/B testing ABR

wait for enough samples ( ~ 1 million per group)

compare key metrics• rebuffering rate• rebuffering ratio• user engagement• average quality, quality switches

iterate/circle around best samples

State of ABR - stream tech comparison - VoD

number of rebuffering, percentage per tech worldwide

native 83.6%

hls.js 89.4%

flashls90.6%

hls.js,s=15,f=4 90.7%

hls.js,s=9,f=4 90.2%

State of ABR - stream tech comparison - live

number of rebuffering, percentage per tech worldwide

native 70.4%

hls.js,s=0,f=0 73.6%

flashls80.6%

hls.js,s=9,f=5 79.3%

hls.js,s=7,f=5 74.7%

nb of level switch - live

hls.js,s=0,f=0

hls.js,s=9,f=5

network deliveryuse streaming metrics to rank CDNs per region / ISPredirect stream to best CDNs based on past history

transcodingA/B test different fragment duration

media engine / player optimizationstart renditionprogressive fragment parsing (Fetch API)

Next data driven improvement

tommy.nacass@dailymotion.comguillaume.dupontavice@dailymotion.comhttps://github.com/dailymotion/hls.js

thanks!