This white paper introduces a new peer-assisted approach to video streaming designed to overcome limitations of content delivery networks (CDNs). It explains how peer-to-peer streaming can represent a key advantage for broadcasters by enabling them to scale up, improve quality, and handle traffic peaks while reducing costs and network burden. A case study showed the solution achieved up to 58% peer streaming and ensured continued streaming for 50% of users during a server outage. Peer-assisted streaming optimizes video delivery as demand increases by leveraging growing numbers of viewers to share content.

1. PEER-ASSISTED
ADAPTATIVE STREAMING:
THE KEY TO MANAGING
EVER-GROWING
ONLINE VIDEO TRAFFIC
W H I T E P A P E R

2. FASTER DELIVERY + LESS BANDWIDTH + INSTANT SCALING
INTENDED READERS
This White Paper is intended for online broadcasters, CDNs, video platforms and professionals
all along the online video distribution chain.

3. 3
CONTENTS
CONTEXT: A BOOMING ONLINE VIDEO MARKET IN
SEARCH OF TOMORROW’S SOLUTIONS
PEER-ASSISTED DELIVERY: OPTIMIZE VIDEO PLAYOUT
AND MINIMIZE INFRASTRUCTURE RISKS
CASE STUDIES: OVER 50% PEER-TO-PEER STREAMING
ON A LARGE VOD PLATFORM
FINAL REMARKS
1
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3
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4. 4
ABSTRACT
This White Paper introduces a new peer-based approach to video
streaming designed to overcome the limitations imposed by current
Content Delivery Network (CDN) infrastructures and distribution
techniques. It explains through statistics and case studies how peer-
assisted video delivery can represent a key competitive advantage,
enabling broadcasters to scale up, improve quality of streams and
handle traffic peaks, all while reducing costs and lightening the
burden on saturated network infrastructures.

5. 5
CONTEXT:
A BOOMING ONLINE VIDEO MARKET IN
SEARCH OF TOMORROW’S SOLUTIONS
A GROWING ONLINE VIDEO MARKET
The online video market is experiencing exponential growth with
the combined effect of skyrocketing consumption and increasing
video quality.
Internet traffic is poised to more than double in the next five years.
Today video content represents over 60% of worldwide consumer
traffic. With the growing use of mobile devices and tablets, this
figure is set to jump to up to 90% by 2018.i
According to a recent
Ericsson report, video traffic will grow faster than any other mobile
segment – 13-fold by 2019 – and will soon represent over half of
mobile data use.ii
1
At the same time, video files themselves are growing. In a market
where performance is essential, 4K, or ultra-high definition (UHD), is
quickly becoming the benchmark.iii As consumers come to expect
heightened quality, video distributors will require more and more
bandwidth, as well as infrastructures capable of receiving larger files
and increasing amounts of traffic, if they hope to ensure a satisfactory
end-user experience.
Figure 2: Projected growth in mobile video and total mobile trafficFigure 1: Projected growth in video and total Internet traffic
i. Cisco® 2014 Visual Networking Index
ii. Jim O’Neill, “Mobile video traffic to
grow 13X by 2019, straining already
congested networks” 09 June 2014.
http://www.ooyala.com/ videomind/
blog/mobile-video-traffic-grow-13x-
2019-straining-already-congested-
networks#sthash.zRB5X5f0.dpuf
iii. A UHD file is 16 times larger than the
same file in HD.

6. 6
A UNICAST MODEL SHOWING ITS LIMITS
Current distribution models are already starting to show their
limits. As Akamai’s Kurt Michel observes, “Increasing broadband
penetration and faster devices make high-quality viewing
experiences possible, but network latency issues and heavy
traffic loads can often result in disappointing video streaming
performance, with frequent pauses for rebuffering.”iv
Even more troubling, outages are multiplying as platforms struggle
to cope with unprecedented demand. Even the sector’s biggest
and most lucrative actors – those that invest huge sums in top-tier
CDNs to ensure content is delivered to millions of users – remain
highly vulnerable. Look no further than the last few months: Just
weeks after problems with the True Detective finale, HBO Go
suffered a crippling outage potentially affecting millions of viewers
during the Game of Thrones season 4 premiere; ESPN crashed
when 1.4 million simultaneous viewers attempted to watch the
US-Germany World Cup match; ABC’s debut live stream of the
Oscars was down for most of the evening.v
Traditional unicast protocols based on one-to-one relations
between client and server have proven insufficient, with frequent
network over-capacity and congestion. Content delivery networks
are racing to palliate the situation by multiplying peering points
and surrogate servers around the globe. This solution, however, is
not scalable ad infinitum and risks to ultimately fail to provide the
reliability sought at an acceptable cost.
What’s more, while content delivery networks can take much of
the burden off of a provider’s origin infrastructure and help deliver
content to users faster, CDN infrastructure is shared among
multiple customers. If one client needs to broadcast a huge
sporting or political event, will other customers be forced to suffer?
The bandwidth wars have only just begun, and those with the
architecture will decide which videos will be delivered at what
speed (see the Verizon / Netflix conflict). As telcos vie to compete
with traditional CDNs, more and more companies are looking for a
slice of the pie, and bandwidth-heavy video content providers will
be at the mercy of potentially unfavorable pricing and distribution
policies.
iv. https://blogs.akamai.com/2013/01/
live-video-streaming-that-can-handle-
traffic-spikes-the-challenge.html
v. For more information on these exa-
mples, see:
http://techcrunch.com/2014/04/06/
hbo-go-still-recovering-from-outage-du-
ring-game-of-thrones-premiere/
http://variety.com/2014/digital/news/
espn-video-streaming-service-cra-
shes-during-usa-germany-world-cup-
match-1201251221/
http://variety.com/2014/digital/news/
abcs-live-internet-oscar-stream-suffers-
nationwide-outage-1201124215/

7. 7
vi. “Les nouvelles frontières de la
diffusion OTT: Multicast & P2P” www.
ovfsquad.fr
vii. Cisco® 2014 Visual Networking
Index
viii. For more information on skewed
video popularity distribution, see:
“Watching Videos from Everywhere: a
Study of the PPTV Mobile VoD System,”
Social networks have a tendency to
skew this distribution even more, to
such an extent that a mere 2% of
content can garner up to 90% of views.
See “Video Requests from Online Social
Networks: Characterization, Analysis
and Generation,” http://www.cs.sfu.
ca/~jcliu/Papers/VideoRequests.pdf
PEER-ASSISTED DELIVERY: OPTIMIZE
VIDEO PLAYOUT AND MINIMIZE
INFRASTRUCTURE RISK
P2P: A VIABLE SOLUTION
To remain competitive, broadcasters will have to ensure high-qua-
lity content at lightening-fast speeds – every time. They will have
to be prepared to support an increasing number of visitors all while
reducing their dependency on traditional delivery networks. Band-
width is a video platform’s largest production cost, and those that
manage to control this expense without compromising quality will
have an edge up.
CDNs admit that additional distribution models are necessary, and
that time is of the essence. One of the largest actors cites peer-
to-peer streaming as a solution that has already proven effective
on a large scale.vi
When combined with traditional unicast delive-
ry, peer-to-peer adaptive streaming presents a viable alternative.
Why? Let’s take a look at two realities:
Peak-hour Internet traffic is growing faster than average
traffic.vii
Over 80% of video traffic is concentrated on 20% of
content.viii
The videos that are and will be in highest demand are also those
being watched by a large number of viewers at the same time.
Peer-to-peer streaming allows simultaneous users to exchange
video segments among themselves rather than each connecting
to a server to do so. The system thus effectively overcomes seve-
ral of the scalability obstacles presented by the video market.
First, it largely reduces broadcasters’ reliance on CDNs for content
distribution, drastically reducing bandwidth costs, freeing up
congestion and protecting them from infrastructure malfunctions.
2

8. 8
With a simple CDN-based
model, users download
directly from the server,
using up bandwidth and
creating congestion.
With a hybrid peer-to-peer
system, viewers can supply
each other with the content,
optimizing traffic flows
and ensuring better QoS.
Decentralizing this exchange of data also significantly improves
the quality of service for the end user, as each viewer is able to
collect the segment needed from the source that can provide
it most quickly. Lastly, it turns inevitable user volume increases
into an asset, as the solution works better the more viewers are
watching the same content.
THE STREAMROOT ANSWER 
StreamRoot has developed a hybrid peer-to-peer video streaming
solution based on the latest Internet technologies: HTML5,
JavaScript, Media Source Extensions and WebRTC. Unlike other
peer-to-peer solutions, StreamRoot’s technology is transparent,
requiring no plugin, extension or other installation on the part of
end users.
When a StreamRoot user accesses a webpage, the video content
beginsloading directly fromtheserver.Atthesametime, theviewer
connects to the StreamRoot tracker and retrieves an intelligently
selected list of peers, establishes a direct connection with them
and requests video segments. If the peers cannot provide the
segments quickly enough, it automatically switches back to the
origin/CDN server, guaranteeing at the very least the same quality
of service as a CDN-only solution.

9. 9
Streamroot leverages two new cutting-edge technologies. The
first, WebRTC, is a new standard that allows users to establish
direct and secure real-time communications with other users
without worrying about NATs and firewalls. It is included natively
in browsers as a javascript API, and is available as an open-source
library distributed by Google for easy integration into any type of
device.
The second is Media Source Extensions, another web standard
designed for dynamic management of video streams directly in
HTML5. Avoiding the need to rely on cumbersome Flash systems,
MSE has already been adopted by most browsers, and is used by
default by Netflix and YouTube. Like WebRTC, it is also becoming
standard for mobile devices, set top boxes and smart TVs.ix
Harnessing these technologies, our solution can be decomposed
into three main modules:
Media engine module
This module enables adaptive bitrate streaming play-
back in HTML5 and Flash. It supports the newest
MPEG-DASH streaming standard, as well as older for-
mats like Smooth Streaming and HLS. It uses dynamic
adaptive streaming algorithms based on the end-user’s
bandwidth to provide the best possible experience the
viewer’s device and connection can offer at a given
time.
Peer-to-peer module
This module enables direct peer-to-peer data trans-
fer between viewers. It uses multiple proprietary
StreamRoot algorithms to optimize exchanges in both
Live and VOD playback modes. Format agnostic, it can
be used with DRMs and integrated into a custom player
via a media interface. Finally, it gathers several useful
analytics on the viewer’s performances and behavior.
Tracker
Built on lightweight and scalable technologies like
Node.JS and Redis, the tracker serves as a relay for es-
tablishing peer-to-peer channels, dynamically selecting
the best peers based on geographical and topological
criteria. It also provides the security required by a pro-
fessional video content distributor: geoIP and domain
restriction, along with content integrity verification.
ix. For more technical information on
WebRTC and Media Source Extensions,
consult the World Wide Web Consor-
tium’s (W3C) Editor’s Drafts: http://dev.
w3.org/2011/webrtc/editor/webrtc.
html and https://dvcs.w3.org/hg/
html-media/raw-file/tip/media-source/
media-source. html.

10. 10
Today, StreamRoot provides the first and only workable peer-
based alternative to unicast distribution that has been tested on a
significant scale. The system is currently compatible with Internet
browsers that have adopted WebRTC: Chrome, Firefox and Opera.
Internet Explorerx and Safari are likely to follow suit, making the
solution available on all major desktop systems. Mobile (Android
and IOS) and Smart TV compatibility is currently under develop-
ment and should be fully functional in 2015.
P2P helps minimize infrastructure risks
Despite their limitations, Content Delivery Networks are
an important part of today’s media workflow. Peer as-
sisted delivery can easily work in tandem with a CDN,
optimizing the overall streaming experience, while
at the same time reducing economic dependence on
CDNs and ensuring that viewers can continue watching
their content even if the CDN and local server expe-
rience temporary outages.
P2P cuts costs
Initial tests show that bandwidth costs can be reduced
by up to 70% with an effective peering solution in place.
P2P optimizes video playout as demand rises
Traffic peaks are no longer a source of stress but an
advantage, as peer-to-peer systems work better the
more peers there are available to share content, and
can greatly improve the scalability of the streaming
architecture.
x. Microsoft co-authored the draft speci-
fication for WebRTC 1.1.

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4:10 4:20 4:30 4:40 4:50 5:00 5:10 5:20 5:30 5:40 5:50 6:00 6:10 6:20 6:30 6:40 6:50 7:00 7:10
CDNP 2P
CASE STUDY: OVER 50% PEER-TO-PEER
STREAMING ON A LARGE VOD PLATFORM
P2P: A VIABLE SOLUTION
StreamRoot recently partnered with a Russian video-on-demand
platform to test its peer-to-peer solution on the website’s most po-
pular video during a Friday night peak.
The following parameters were used:
120 minutes of video, in MPEG-DASH, h264/AAC,
at 1,000 kbps
a large geographical area spanning 6 Russian-speaking
countries
2,089 users at peak, i.e. a total bandwidth of 2.1 Gbps
or 1TB per hour
This trial clearly demonstrated the scalability of the P2P model, as
the more peers there were, the more data was transferred between
them.
In this trial, StreamRoot achieved up to 58% peering, with percen-
tages rising at peak use times (42 to 58% streaming at traffic
peaks).
3
Streaming traffic from 4 pm to 7:10 pm
on the site's most popular video
Time
Volumestreamed(inGB)

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6:15 6:16 6:17 6:18 6:19 6:20 6:21 6:22 6:23 6:24 6:25
0
6
12
18In the middle of the test, the origin server went down
entirely from 6:15 to 6:19 pm. P2P streaming ensured
halfOftheserviceduringtheoutage–50%ofuserswere
entirely unaware that the server had malfunctioned.
This case study helped demonstrate:
P2P requires a relatively low critical mass.
For effective peering, the critical mass for a 120-minute
video file (i.e. P2P > 30%) is less than 100 simultaneous
viewers. For a 10-minute video, only 20 peers would be
needed.
P2P is an effective safeguard against server outages
Peers ensured 50% of the service that would have been
completely lost by the server outage.
P2P optimizes video playout as demand rises
The overall average download speeds are 14% higher
with peer-assisted delivery, and efficiency improves
greatly with geolocation and topology based prioritiza-
tion algorithms.
Time
Volumestreamed(inGB)
Momentary Server Outage

13. 13
FINAL REMARKS
With exponential growth in viewer numbers, exploding file sizes
and increasing use of mobile devices and tablets, the online video
industry is poised for unprecedented demand. As recent outages
have shown, even the most robust infrastructures are not ready to
handle the influx of users that large broadcasters are beginning to
experience today. Another model is needed in addition to traditional
unicast distribution. Peer-to-peer adaptive streaming provides a
viable, scalable supplement to traditional CDN distribution. With
its ability to transform increasing viewer numbers into an asset,
peer-assisted streaming based on the latest Internet technologies
such as HTML5, Media Source Extensions and WebRTC can offer
broadcasters a key competitive advantage, enabling them to
reduce costs, improve streams and lighten the burden on saturated
network infrastructures.
4

14. ABOUT STREAMROOT
StreamRoot offers a solution for video streaming combining standard unicast
delivery (e.g. CDN) and peer-to-peer protocols based on HTML5 and WebRTC.
Founded in France in 2013 by three engineers from Ecole Centrale de Paris,
StreamRoot participated the Le Camping and Techstars Boston accelerator
programs and has been recognized with numerous awards including the Trophée
Startups Numérique and Hello Tomorrow Challenge.
At the leading edge of HTML5 adaptive streaming technology, StreamRoot created
the first MPEG-DASH peer-assisted video player in HTML5 working for both Live
and Video on Demand streaming, and has since expanded its expertise to other
adaptive streaming formats and platforms. Using WebRTC, our Peer-to-Peer API
creates an edge network made up of viewers, which relieves broadcasters’ server
infrastructures and bandwidth without requiring any action from the end-user.
Now headquartered in the United States, StreamRoot is currently expanding its
customer base in America and confirming the efficiency of peer-assisted delivery
with large-scale use cases.
For more information or to try StreamRoot: contact@streamroot.io.