Imagine you missed the finals of Super Bowl or the Oscars night. What would you do? Watch it later over the internet, right? But consider the fact that making live streaming or Video-on-demand possible over the internet is a complex thing. This document simplifies the whole concept for you including capture and distribution of content using Windows Media Services. Calance is an industry leader in information technology solutions. Find out more about it here http://www.calanceus.com
From Event to Action: Accelerate Your Decision Making with Real-Time Automation
Creating Live Broadcasting Solution using Windows Media Services
1. Creating a Live Broadcasting Solution
using Windows Media Technologies
Prepared by
Calance Corp.
Feb, 2006
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2. Creating a Live Broadcasting Solution using Windows Media Technologies Page ii
Table of Contents
1. Introduction................................................................................................................................ 1
2. Streaming Media Concepts........................................................................................................ 2
2.1 Understanding Bandwidth................................................................................................................2
2.2 Live and On-demand Content..........................................................................................................3
2.3 Using Windows Media Technologies............................................................................................... 3
2.4 Planning Considerations...................................................................................................................6
3. Management Application......................................................................................................... 10
4. Hosting with Vendors............................................................................................................... 12
4.1 Akamai Streaming...........................................................................................................................12
5. References.................................................................................................................................14
Proprietary and Confidential
3. 1.Introduction
Live video broadcast of popular events (e.g. sporting events like the Super Bowl or Olympics, The
Oscars or Grammy award) is no longer limited to the TV audiences anymore. There is a growing
demand from people with internet connection to be able to view these broadcasts over the internet –
on their personal computers. There is also a demand for archived broadcasts of such events – in
case people missed the original broadcast. So, the media content providers across the globe are
selling both the “live” content as well as archived content (also called Video-on-demand).
A traditional TV broadcast has few limitations – first the audience has to be in front of a TV probably
at their home. Broadcast over the internet eliminates that hurdle and anyone with a computer with a
(high speed) internet connection can tune in. Secondly – TV still has no mechanism for protecting the
copyright of the content and people can freely copy the broadcast. With DRM (Digital Rights
Management) the broadcasts over the internet can be made secure and protected. These internet
broadcasts also gives the audience to pick-and-choose the shows they like to watch. This new
broadcasting mechanism also provides better and more targeted advertising opportunities for the
content provider.
For companies which broadcast live events, typically they save the content of the live event and allow
people to view that off-line also. That’s why most media delivery solutions include streaming live
content and also “video on demand”.
Given today’s high bandwidth availability, the live content is no longer limited only to computers; it can
even be made available to mobile phones or handheld computers (PDAs).
But, let’s also keep in mind that building live streaming capabilities over the internet is a complex and
costly project. Since the video traffic consumes much more bandwidth than a traditional website
displaying text and images – proper infrastructure needs to be in place for both the content provider
and the viewer. The content provider needs to setup a reliable and scalable architecture to take care
of the ever-growing demand and the viewer also needs to have access to a high internet bandwidth
to ensure better viewing experience.
There are multiple popular formats for capturing and distributing digital video content. This white
paper focuses on the Microsoft Media Technologies as the format.
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4. 2.Streaming Media Concepts
Streaming is an emerging technology. Streaming media is generally - audio, full-motion video, and
multimedia content. For our purposes, three primary characteristics combine to define streaming
media, as explained below:
Streaming media technology enables real-time or on-demand access to audio, video, and multimedia
content via the Internet or an intranet. Streaming technology enables the near real-time transmission
of events recorded in video and/or audio, as they happen—sometimes called “Live-Live,” and
commonly known as Webcasting. Streaming technology also makes it possible to conveniently
distribute pre-recorded/pre-edited media on-demand. In other words, media that is stored and
published on the Web in streaming formats can be made available for access at any time.
Streaming media is transmitted by a media server application, and is processed and played back by
a client player application, as it is received. A client application, known as player, can start playing
back streaming media as soon as enough data has been received—without having to wait for the
entire file to have arrived. As data is transferred, it is temporarily stored in a buffer until enough data
has accumulated to be properly assembled into the next sequence of the media stream. New
pseudo-streaming techniques, such as progressive download, allow content in some streaming
media formats to start playing before it is completely downloaded. So, while the ability to begin
playback prior to completing file transfer is a characteristic of streaming, it is not, in and of itself, a
differentiating factor.
A streamed file is received, processed, and played simultaneously and immediately, leaving behind
no residual copy of the content on the receiving device. An important advantage of streaming media
(unlike either traditional or progressive download) technology is the copyright protection it provides.
No copy of the content is left on the receiving device. Therefore, the recipient can neither alter nor
redistribute the content in an unauthorized manner. This greatly reduces the risk of content being
misused or “pirated”.
2.1Understanding Bandwidth
For streaming to work properly, the player application must play the audio and video content at a
steady and continuous rate. If the stream is not continuous, the picture and sound will either stop or
play back unevenly. This uneven playback occurs when the content is streamed at a bit rate that is
higher than the bandwidth available on the network.
The amount of time needed to download the file is directly related to the size of the file, the available
bandwidth of the network, and the speed of your modem or network interface card.
When preparing content for streaming over the Internet—a process called encoding—it is important
to consider the bandwidth that is available to the people who will be playing the stream, and then
select a bit rate that is appropriate for that bandwidth.
For example, a person with a 28.8 Kbps modem can potentially receive 28,800 bits per second. But
it’s much more likely that they will receive less because of network overhead. So, if you are
connecting to the Internet over a modem with a connection speed of 28.8 Kbps, expect that the
bandwidth available for transferring data is no better than 20 Kbps, maybe less.
The following table illustrates the different kinds of network connections available today, and the
maximum bandwidth typically associated with each.
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5. External connection Bandwidth
Dial-up 28.8 to 56 Kbps
ISDN 64 to 128 Kbps
DSL or cable 128 to 768 Kbps
T-1 1.5 megabits per second (Mbps)
T-3 45 Mbps
DS-3 45 Mbps
Internal connection Bandwidth
Cat5 100 Mbps
High-bandwidth Cat5 119 Mbps
Fiber optic 100 Mbps to 13 Gbps
2.2Live and On-demand Content
Two delivery options are possible when streaming: live and on-demand content.
1. Live content is often used when viewers want to see and hear an important event as it is
occurring. Examples might be a sporting event, presidential election, or breaking news.
2. Streaming on-demand content is the appropriate choice for times when the message is not
time-critical. This delivery option enables you to re-broadcast a live event to users who
missed it the first time. They can request the stream when they want to watch it, and can
control the playback to meet their needs.
On-demand streaming has potentially lower bandwidth requirements because hundreds (or
thousands) of users may not be required to be serviced concurrently.
2.3Using Windows Media Technologies
The delivery of information content through Windows Media technologies is composed of the
following processes:
· Capturing
· Encoding
· Distributing
· Delivering
· Playing
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6. The following diagram shows the process of converting video streams and then delivering to the
user:
Figure 1: Process flow of working with Streaming Media
To complete a broadcast stream using Windows Media technology, one must use a Windows Media-compatible
encoder, server, and player. This section describes the functional purpose of these
components as well as the other processes associated with the components.
2.3.1Capturing Data
The capture phase takes place when you pull audio and video from its source and onto the computer
using a capture card. If the source is analog, then the capture card converts the analog data to digital
form before depositing it on the computer (please note that during this conversion a slight quality loss
occurs).
Many capture cards include a simple capture program that allows you to save the digitized media as
an uncompressed .avi file, which is a standard Microsoft video file format. While streaming a live
event, saving the content into a file is not necessary because, live or on-demand, the next phase of
this process is encoding.
2.3.2Encoding with the Windows Media Encoder
Without compression, much content would never be suitable for streaming; its large size would
choke network infrastructure. Encoding compresses content so it can be streamed over a network or
Internet. Encoders use codecs (compressor/decompressor), which are algorithms that calculate and
apply the amount of necessary compression, based on the quality of the content and the intended
transfer bit rate. After compression, the data is encoded into a streaming media format, such as
Windows Media Video (WMV) or Windows Media Audio (WMA). Encoding sources from your raw
captured data, and connects to the server that you use for distribution.
Capturing and compressing content is a CPU-intensive process, and maintaining connections with
multiple Players during the streaming process is memory-intensive. To improve performance and
encoding quality the following infrastructure needs to be considered:
· Fast processors as well as dedicated computers for the encoding process
· A high-performance hard disk for the dedicated computer
· Audio and video cards (preferably certified by Microsoft)
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7. · Windows XP Professional as the operating system
· A network that can accommodate the bandwidth required by both the stream from the encoder
and the overhead for other network traffic.
· Windows Media Encoder 9 Series offers robust protection of your content through digital rights
management (DRM).
2.3.3Distributing with Windows Media Services
With the content digitized to a file on a computer from the capture phase of the process, the next
step is to distribute it. Because of the protocols used and the limitations of Web servers, streaming
content requires a streaming media server. These servers support a different protocol that maintains
a constant connection with the Player, and thus delivers a successful, live broadcast. They can log
user data, which allows the content provider to understand trends, identify bottlenecks, or
troubleshoot performance issues on the server. Streaming media servers support streaming content
at multiple bit rates, which can be useful while streaming content to a number of clients who are
accessing the server at various connection speeds.
Windows Media Services 9 Series affords several benefits as a server choice:
· Inclusion of Windows Media Services as an option of Windows Server 2003, Standard Edition,
Windows Server 2003, Enterprise Edition, or Windows Server 2003, Datacenter Edition reduces
your bottom-line costs.
· Multicast content-delivery is available only when Windows Media Services is used with Windows
Server 2003, Enterprise Edition or Windows Server 2003, Datacenter Edition.
· Robust logging and monitoring functionality allows you to pinpoint network congestion.
· Full-provisioning allows you to automatically program and seamlessly update digital media
content on the fly, including support for lead-in and interstitial ads.
· Remote access through the server snap-in allows you to administer the server from the Microsoft
Management Console (MMC), a Web browser, or command-line scripts.
· Ability to run the server on the same computer that acts as the domain controller results in
reduced infrastructure costs.
· Plug-in models for the server enable developers to build their own custom digital media solutions
and easily extend the entire Windows Media 9 Series platform.
· Authentication and authorization plug-ins control access to media content for your broadcast
delivery.
· Scalable network solution affords a solution that grows as your company grows.
Windows Media Services 9 Series includes a cache/proxy platform, hence it can be extended to
scale out in an easy-to-manage distributed architecture that conserves network bandwidth,
decreases latency and reduces server load. The resulting architecture can scale to effectively
support the largest streaming audiences.
2.3.4Using Windows Media Player
After the content is distributed, it is ready for people to view it. To play back a streamed file,
subscribers log into the designated web site by entering their credentials, and after verification of the
same, they get connected to the Media Server to start the stream.
Although several player applications are available, Windows Media Player 9 Series will be enabled as
the default choice.
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8. The complete landscape of the streaming solution includes all the above components and the end-to-end
solution looks like the following:
Figure 2: Infrastructure landscape for Streaming Media solution
2.4Planning Considerations
A live broadcast requires addressing of a number of different issues:
2.4.1Capacity planning
A common problem encountered when deciding on a base media-server platform is estimating the
amount of storage required for on-demand media files. It is important to not only plan for immediate
storage needs, but for future demands as well.
There are three factors that contribute to the size of a media file:
· Actual encoded bit rate
· Content type
· Content length
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9. A video with high motion (sporting event) generally produces a larger file size than a video with little
motion (news broadcast)
To estimate the file size of a captured stream, the following calculation can be used:
(X Kbps * S seconds) / 8192 = Y MB
Where X is the encoded bit rate in kilobits per second (Kbps)
S is the length of the stream in seconds
Y is the approximate total file size in megabytes (MB)
Once the bit rates are decided, the content must be encoded. The following chart can be used to
determine storage requirements for on-demand media files.
Aggregate bit rate (Kbps) Minutes of content Approximate file size (MB)
22 30 4.8
37 30 8.2
50 30 11
100 30 22
300 30 67
1000 30 220
It is also important to understand the relationship between the video resolution/frame rate and the
streaming bit-rate:
Window size (resolution) Frames per second (fps) Color depth (bits) Data rate per second
640 x 480 30 24 27.65 MB
640 x 480 15 24 13.83 MB
320 x 240 15 24 3.46 MB
160 x 120 15 24 865 KB
The following chart shows the different connection speeds to Internet and their throughputs:
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10. 2.4.2System Planning
The hardware landscape of the Streaming solution will depend on quite a few parameters – the
number of concurrent users, the quality of the broadcast etc. A typical installation as described in
Figure 2 will have the following software components:
· Microsoft Windows Server 2003 (Standard Edition, Enterprise Edition or Datacenter Edition)
o Windows Media Services 9 Series is available as an optional component
o Microsoft IIS Server is available with Windows Server
· Microsoft ISA Server
The following minimum hardware configuration is also recommended by Microsoft:
Processor: 550 megahertz (MHz)
Memory: 1 gigabyte (GB) RAM
Network Interface Card (NIC): Ethernet card, Transmission Control Protocol/Internet
Protocol (TCP/IP)
Free hard disk space: 521 megabytes (MB) (6 MB for system files, 15 MB for installation,
and 500 MB for content storage)
Please note that the exact number of servers will depend on the network load and also on the level of
redundancy planned. Most commercial installations will include a server cluster. A server cluster is a
group of Windows Media servers working together to stream content. Although clients connect to the
cluster using a single URL, all of the servers share the streaming load in order to reduce the load on
an individual server.
For large-scale deployments of Windows Media Services the following recommendations are made:
· Upgrade from a single-CPU server to a multiple-CPU server.
· Install additional network interface cards, or upgrade the existing network interface card to
support a higher bandwidth network connection.
· Add additional servers running Windows Media Services to the streaming media system
installation and use Network Load Balancing to distribute the server load.
· Distribute cache/proxy servers throughout the network and implement a content replication
program to distribute content closer to the clients and relieve some of the demand on the
origin servers.
· Set the network switches that will be processing streaming media requests and
transmissions to full duplex mode to maintain an uninterrupted information flow.
2.4.3Performance Statistics
Using the above calculations for the estimated bandwidth requirement with the estimated audience
volume, capacity allocations for the network and server system for accommodating demand can be
determined.
To estimate the total required server capacity, the following calculation can be used:
Required bit rate per user * estimated audience volume = Total server capacity
For example, if broadcast content is delivered at a bit rate of 300 Kbps to 500 concurrent users, the
server system and network must be capable of handling 150 Mb per second. Please note that the
actual capacity of a server varies based on manufacturer, class, operating system, and other factors.
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11. The following table demonstrates the need for additional server capacity as the number of users and
content bit rate increases.
Data rate of streams Max. audience
size
Bandwidth needed Example connection
100 Kbps 100 10,000 Kbps or 10 Mbps 10 Mbps fractional T3
200 Kbps 6 1,200 Kbps or 1.2 Mbps T1
200 Kbps 200 40,000 Kbps or 40 Mbps T3
300 Kbps 150 45,000 Kbps or 45 Mbps T3
Windows Media Services 9 Series is the most scalable streaming platform in the industry today. If
you are streaming live content, the number of clients is very high, since disk I/O in many cases is a
limiting factor when dealing with on-demand streams. In practice, it is not recommended to run
production systems at maximum capacity for sustained periods, but rather at a more conservative
level of up to 50% average peak utilization.
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12. 3.Management Application
Web sites with streaming media and video on demand need a good content management solution.
This application allows the broadcasting company to manage the users of their service (typically
subscription based), manage the content library, and manage the advertisements which are also
shown during the live or on-demand broadcast. The following application architecture suits most such
requirements:
Figure 3: Typical Architecture of Content management Solution
Content Management: This allows the site administrators to manage the content of the site.
The site administrators can change the look and feel of the site, add new content, archive old
content, and add promotional material before a big event. Depending on the number of site
administrators and the complexity of the business, this Content Management System can have
advanced features like workflow, scheduled publishing etc. Depending on the requirement a custom
application can be developed or a CMS package can be chosen.
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13. System Management: The system administrators will have to monitor the health of the
application 24x7 and fix errors when they occur. This includes monitoring the load on the system, the
performance of the different components of the system etc. Most of these activities can be
automated and appropriate alerts are sent in case of any event that needs the attention of the system
administrators.
Ad Management: Most streaming content providers bundle their Ads along with the broadcast.
This can be a moving banner at the bottom of the screen or it could be commercials during the
breaks in the event. Since the audience is browsing over the internet, it is fairly easy to understand
their geographical location and that allows the content provider to stream targeted Ads based on
geography. Since most of the user base for live content streaming is subscription based, targeted
media campaigns for specific group of users is also possible. This needs an Ad management
solution and as above, this also can be developed or a standard software package that suits the
requirements can be utilized.
Subscription Management: This allows the content provider to manage the user base of their
services. The users typically need to subscribe for the services. There can be a lot of different
subscription models – flat fee, pay-per-view, monthly fee etc. The subscription system will manage all
such requests and will also interface with a payment gateway for realizing the transactions.
Whenever users attempt to view the live or on-demand content, they will have to authenticate via this
module before they can access the content. This module should have strict authentication and
authorization measures and needs to be hacker-proof and fraud-proof.
Content Personalization: The content provider will be able to harness the power of the content
management system and the subscription system to personalize the content for their users.
Personalization will allow the provider to present pre-selected content to the users and will minimize
the users’ time to search for content.
Content Delivery: In today’s world, PCs connected to the Internet is not the only medium via
which the content can be delivered to the users. Handheld devices like PDAs or even mobile phones
are emerging as content delivery channels. The content delivery to different channels will generate
additional revenues for the provider.
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14. 4.Hosting with Vendors
The cost of building the infrastructure to host live events and on-demand video streaming is quite
significant. At the same time, to ensure a smooth 24x7 operation needs investments in redundant
hardware which adds to the cost. The user-base can be very diverse depending on the type of the
content. For example, for a live sporting event, users from North America, Europe and Asia might
log-in at the same time to watch the broadcast. This means that the provider needs to have proper
infrastructure, with redundancy, in place in multiple locations. The infrastructure includes content
delivery servers, proper reliable bandwidth and supporting staff.
There are companies with already established infrastructure who provide services to broadcast
events and content. In this scenario, the content provider needs to deliver the content to these
hosting companies and they subsequently deliver to the end-users across the globe.
4.1Akamai Streaming
With Akamai Streaming (http://www.Akamai.com), content providers can take advantage of a high
quality, extremely reliable streaming service to provide on demand product demos, corporate
presentations, live news, sports, or entertainment events, music, or movies. Another advantage of
Akamai is their support for a variety of media formats.
The EdgeSuite Streaming solution from Akamai utilizes Akamai's proprietary streaming technology
and the world's largest fault-tolerant network to deliver consistent and reliable, high-quality streams
for on demand and live events. The service transfers original streams to the Akamai Platform —
resulting in a lossless stream delivered from the edge of the Internet every time.
For on demand streaming: Before streaming even begins, EdgeSuite Streaming downloads a
stream from storage and transfers it reliably to the optimal Akamai streaming servers at the edges of
the Internet. From there, the streaming servers deliver the original-quality streaming media file to the
end users.
For live streaming: To avoid the jerkiness caused by packet loss, EdgeSuite Streaming sends
multiple copies of the same stream over different routes from an Akamai Entry Point to the optimal
streaming servers at the edges of the Internet. These copies are then combined to form one
complete, original-quality stream, which is sent from the streaming servers to the end users.
Event management: Akamai's Event Management Console makes reserving and reporting on
events easier than ever. Leverage our automated system to provision, start, and report on streaming
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15. events. This system gives you event management, removing the traditional complexities of manual
event reservation.
Security: The Akamai Streaming Authentication solution allows content providers to authenticate
requests for streaming content, both live and on demand. This level of security provides a scalable,
protocol- and format-agnostic, extensible architecture for controlling access to your company's
valuable content.
There are many other companies providing similar solutions to host and stream live content. There
are Microsoft certified Premier Hosting providers who can provide Windows Media formatted content
reliably. Here is a list of a few such vendors:
Limelight Networks
Limelight Networks is a comprehensive digital delivery network with services that
include live and on-demand streaming, media downloads, content delivery,
storage and hosting. Limelight Networks utilizes a distributed platform with
multiple backbone connections for the most efficient delivery at affordable rates.
Nine Systems Corporation
Nine Systems' media distribution system, Stream OS, uses multiple content
delivery networks for high-performance streaming content delivery. Nine Systems
offers the greatest aggregate capacity and broadest global reach by providing a
seamless integration of multiple delivery infrastructures controlled and managed
through their revolutionary array of reporting and statistical applications.
SAVVIS Communications
SAVVIS provides complete streaming media creation and delivery services using
the Microsoft Windows Media 9 Series streaming network. We have the
experience to assist you with all your streaming needs, including solutions for
media and entertainment and corporate communications. Our team of expert
encoders, developers, and producers can create high-impact streaming content
for you and ensure that end users enjoy the best possible viewing experience.
VitalStream, Inc.
VitalStream offers customers a full range of services including media streaming,
managed servers, web hosting and other consulting services. Digital broadcasting
services include pay-per-view, on-demand streaming, live-event streaming, and
encoding services (through Partners). VitalStream's managed hosting services
enable customers to outsource their IT department at a significant cost savings.
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16. 5.References
· Help Documentation on Windows Media Technologies
(http://www.microsoft.com/windows/windowsmedia/knowledgecenter/helpdocs.aspx)
· Windows Media Services 9 Series FAQ
(http://www.microsoft.com/windows/windowsmedia/9series/server/faq.aspx?section=WINDO
WSMEDIASERVICESBASICS&question=WINDOWSMEDIASERVICESBASICS2)
· A Streaming Media Primer from the Adobe Dynamic Media Group
· Akamai Stream Services (http://www.akamai.com/en/html/services/streaming.html)
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