vedantu @ kranky geek
TRANSCRIPT
www.vedantu.com
Introduction
Marketplace of Teachers
Growth
300Hours in a Day
10000+ Hours in a Month
Live Classroom
Models
One to One - P2P
Signalling Server(Node.js)
coTURN Server
SignallingWhiteboard Data
StatisticsRecording
SignallingWhiteboard Data
StatisticsRecording
MediaTeacherStudentN
AT
NAT
❏ Requirements❏ Session replay❏ Academic Review❏ Engagement analysis
❏ P2P WebRTC and recording❏ Local storage of recordings❏ Time to upload recordings❏ Dependent on teacher & student to upload independent streams❏ Huge size of recordings
❏ Convert audio to mp3 sampled at 8000 Hz❏ Mobile CPU consumption to reduce audio upload size
Recording
Models
One to One & One to Few Media Server
Media Server
Teacher
StudentStudent
Signalling Server MediaMedia
Media
One to Few:P2P mesh not an option
Media ServerCentral recording, SimulcastEvaluation of Jitsi / 3rd party
Academic Quality
Verbal Interaction Whiteboard Usage Content Usage
- Conversation Analysis- Tone Analysis- Pace Analysis
- Space Usage- Handwriting- Activity
- Images and Shapes- Annotations
Flagging, Reporting, Quality Control
Session Quality
[TBD] All statistics we collect - graphical representation
★ Disconnects and Statistics★ Support★ Correlation with Engagement Analysis
WebRTC on Mobile
❏ Generate binaries for android using depot tool
❏ Support x86, ARM architectures ❏ Increased app size by ~5 MB
❏ Average session duration 60 mins❏ 300+ hours of live sessions in last 3
months❏ Statistics (1 hr. session)
❏ 15-20% battery consumption❏ 2-3 network disconnections
Statistics
Average Session Length 60 mins
TURN usage 24%
Disconnects / Session 1.46
Cloud telephony calls (bad networks) 5.3%
Initial connection establishment 1.7 sec
RTT 272 ms
Jitter 7 ms
Packet loss 0.08%
Issues
❏ Browser updates and compatibilityFirefox - Delay in permission popupFirefox - BugID:852665 - Report WebRTC transport termination
❏ P2P - Session RecordingRemote stream recording API (recently available in Chrome 49)Storage and Replay for P2P
❏ RTC Data connection cannot be used for Whiteboard dataFirefox issue - ICE state changes not detectedApplication level keep-alive (ping pong) for detecting connection stateIssue with reconnect and performance
Look forward to
❏ VP9 and all its goodness
❏ Call summary❏ Quality - MOS, PESQ score❏ Jitter❏ Packet loss❏ RTT❏ Bandwidth❏ Duration
❏ API for bandwidth limiting instead of SDP munging
Journey ahead
❏ Build the Knowledge sharing network
❏ Connect at scale
❏ Truly democratize education
THANK YOU