Creating a Live Broadcasting Solution using Windows Media Technologies

Prepared by Calance Corp.

Feb, 2006

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Creating a Live Broadcasting Solution using Windows Media Technologies Page ii

Table of Contents

1. Introduction................................................................................................................................ 12. Streaming Media Concepts........................................................................................................ 2

2.1 Understanding Bandwidth................................................................................................................22.2 Live and On-demand Content..........................................................................................................32.3 Using Windows Media Technologies............................................................................................... 32.4 Planning Considerations...................................................................................................................6

3. Management Application......................................................................................................... 104. Hosting with Vendors............................................................................................................... 12

4.1 Akamai Streaming...........................................................................................................................125. References................................................................................................................................. 14

Proprietary and Confidential

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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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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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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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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• 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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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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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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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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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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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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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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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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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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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=WINDOWSMEDIASERVICESBASICS&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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