How OpenWebRTC was used in Ericsson’s and Volvo CE’s Remote Control over Mobile Networks prototype – demoed at MWC 2015. Also a quick review of OpenWebRTC and a few words on the addition of Data Channel support. Presentation by Ericsson Research.

1. OpenWebRTC – Not just
for Video Chat
Kristofer Dovstam
Master Researcher
Multimedia Applications and Protocols, Ericsson Research

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› Mobile first WebRTC client framework
› Permissive Open Source BSD 2-
clause license
› Independent, interoperable
implementation
› Being integrated into WebKit
› Native applications
› GitHub
What is
OpenWebRTC?

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› What is it?
– Not just audio and video, but data too
– Can control reliability and ordering properties depending on needs
– Encrypted real-time data
› OpenWebRTC now with Data Channel support!
– Using the reference SCTP implementation - libusrsctp
– Contributed by Collabora Ltd.
– Has been tested in real use cases…
WebRTC Data Channel

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› Remote Control over Mobile Networks
– Remote control an excavator from a long
way away
– Use WebRTC technology
– Optimize solution for high-performance and
low-latency
› Demo at MWC 2014
– ‘Toy’ excavator
– Earlier internal version of OpenWebRTC
– iPhone
– Oculus Rift DK1
IDEA and History

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…2015

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Excavator
› Research collaboration
with Volvo CE
› Not a product!

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Excavator
› Excavator
– Excavators from Volvo CE
– Modified to handle electrical control
signals
– Powerful Linux PC
– Python application with custom
signaling built on top of
OpenWebRTC

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Audio / Video
Capture
› 2048x2048 24fps
camera
› 360 degree lens
› 52.5 degrees up, 62.5
degrees down
› Avoids stitching artifacts
› Microphone array of four
microphones

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Control Rig
› Simulator from Oryx and
Volvo CE
› Mac OS X computer
› OS X Cocoa application
with custom signaling
built on top of
OpenWebRTC

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› Oculus Rift DK2 (1920x1080 75Hz –
960x1080 for each eye)
– Still much too low resolution!
› Doughnut to panorama texture
mapped on a sphere
› Local rendering minimizes motion-to-
light latency of head movements
› Four channel audio rendered as four
independent sound sources in a 3D
space
Audio / Video
Rendering

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Controls
› Simulator rig with analogue controls
› Computer measures analogue signals
and converts to digital measurements
› Control signals sent via WebRTC Data
Channel to excavator
› Excavator computer converts digital
signals into analogue electrical signals
› It’s alive!

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Media Processing
Architecture
Camera
Microphone Array
Excavator
OpenWebRTC
Audio / Video
Data Channel
OpenWebRTC
Audio / Video
Data Channel
Oculus Rift DK2
Headphones
Control Rig
Network
Mobile, fixed, …
Network
Mobile, fixed, …
Audio
Video
Data
Audio
Video
Data
Audio
Video
Data
Audio
Video
Data

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› Data Channel
– 1 stream
– Unordered
– Unreliable (full control signal
state in every message so
only the newest message is
relevant)
– libusrsctp
› Video
– 2048 x 2048
– ~24fps
– H.264
– OpenH264
– 10Mbps
› Audio
– Single 4-channel stream
– Signed 16-bit
– 48kHz
– Opus
– libopus
– 256 kbps total bitrate
Media Stream Specifications

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Mobile world congress - 2015

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