multimedia research [internet tv ]

8/14/2019 Multimedia Research [Internet TV ]

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How Internet TV WorksHow Internet TV Works

Researchers:

Mohamed Hassan AliHisham Hassan Ali

Supervisor:

Dr. Sayed Abdel Wahab

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TopicsTopics

1. History.

2. Internet TV.

3. Internet TV Types and Cost.

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TopicsTopics

5. Internet Bandwidth and Streaming.5.1 Bandwidth

5.1.1 How to Calculate Download Time (Method 1)

5.1.2 How to Calculate Download Time (Method 2)

5.2 Streaming audio and video

5.2.1Video formats

5.2.2 Flash Video has big advantages

5.2. 3 Flash, King of the Impossible

5.2.4 Lossy compression

5.2.5Why lossy compression in streaming media

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11) History) History

For most of the 20th century, the only twoways to watch television were through:

Over-the-air broadcasts.

An antenna picks up radio waves to transmit picturesand sound to your television set

With cable TV (Wired - Wireless).Wires connect to your TV itself. These wires run from

your house to the nearest cable TV station, which actsas one big antenna.

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22) Internet TV) Internet TV

It's also known as Internet protocoltelevision, or IPTV.

"IPTV is defined as multimedia services such astelevision/video/audio/text/graphics/data delivered

over IPbased networks managed to provide therequired level ofqualityof service and experience,security, interactivityandreliability."

You can watch Internet TV on a computer

screen, a television screen (through a set-topbox) or a mobile device like a cell phone or aniPod.

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SetSet--Top BoxTop Box

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SetSet--Top BoxTop Box

the set-top box is a small computerproviding two-way communications on an

IP network and decoding the video

streaming media. A device that connects to a television and

an external source of signal, turning the

signal into content which is then displayedon the television screen

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44..11) Internet TV Types) Internet TV Types

IPTV services may be classified into threemain groups:

1. Live broadcasts (real-time streaming

video).http://www.wwitv.com/

2. Time-shifted programming.

3. Video on demand.http://www.joost.com/

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CostCost

Cost estimation for deploying an Internet TVservice depends on the following factors:

1. Are you doing "Audio Only" or "Audio andVideo" streaming?

2. Number of days per week[1:7].3. Number of hours per broadcast session

[1:24].4. Number of viewers for each bit rate:

Low (dial up = 34 Kbps) Medium (Low broadband = 150 Kbps) High (High broadband = 350 Kbps)

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Cost ItemsCost Items

PC with high performance Hardware.

Input devices ()

Server for publishing media stream.

Internet Bandwidth for web publishing.

Networking Device.

Load Balancer for load distribution.

Hardware Maintenance.

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55) Internet Bandwidth and) Internet Bandwidth and

StreamingStreaming There are two major things that make

Internet TV possible:

1. Bandwidth.

2. Streaming audio and video.

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55..11) Bandwidth) Bandwidth

Internet likes highways and informationlikes cars.

One car on the highway

Travels quickly and easily. Many cars on the highway

Travels slowly with delay.

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55..11..11) How to Calculate) How to Calculate

Download Time (MethodDownload Time (Method 11))1. Both file size and connection speed

should be converted to bits.

2. Divide the file size by the connection

speed.

Note:

File size measured by kilobytes Connection speed measured by kilobits per second

[kbps]

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How to Calculate DownloadHow to Calculate Download

Time (example)Time (example) Assume we need to transfer 84 KB file

using 56 Kbps connection speed.

1. File size by bits = 84 * 1000 * 8

= 672,000 bits.2. Connection speed by bits

= 56 * 1000

= 56,000 bits per second

3. Time required to transfer

= 672,000 / 56,000

= 12 seconds

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55..11..22) How to Calculate) How to Calculate

Download Time (MethodDownload Time (Method 22))1. Both file size and connection speed

should be converted to kilobytes.

2. Calculate transfer rate by converting

connection speed to (kilobytes persecond)

3. Divide the file size by the transfer rate.

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How to Calculate DownloadHow to Calculate Download

Time (example)Time (example) Assume we need to transfer 84 KB file

using 56 Kbps connection speed.

1. Transfer rate = 56 / 8

= 7 kilobyte per second2. Time required to transfer

= 84 / 7

= 12 seconds

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55..22) Streaming audio and video) Streaming audio and video

A stream is a sequence of data of undeterminedlength.

Watch live or on-demand video withoutdownloading a copy directly to a computer.

Multimedia server uses real-time streamingmedia protocols to make sure the data arrivesin good condition and with all the pieces in theright order.

A plug-in or playeron your computer isrequired to show media --Windows Media Playerand RealPlayer are two popular examples --decodes and plays the video signal.

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55..22..11) Video formats) Video formats

QuickTime, from Apple, plays files thatend in .mov

RealNetworks RealMedia plays .rm files

Microsoft Windows Media can play a fewstreaming file types: Windows MediaAudio (.wma), Windows Media Video(.wmv) and Advanced Streaming Format

(.asf) Adobe Flash player plays .flv files and .swf

animation files

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55..22..22) Flash Video has big) Flash Video has big

advantagesadvantages It has high compression ratios, which

means .flv files tend to be smaller than

other formats.

Flash Video requires a flash player appletrather than a stand-alone video player.

Simple coding.

Includes playback and sizing controls. It uses lossy compression.

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55..22..33) Flash, King of the) Flash, King of the

ImpossibleImpossible Imagine a video as a series of still images

played in sequence.

Flash Video designates certain images,

called frames, as key frames. Flash only records any changes from the

previous key frame.

Storing only the changes reduces file size,but it also reduces the quality of the

video image

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55..22..44)) LossyLossy compressioncompression

Compressing data and thendecompressing it while retrieving datathat is different from the original.

Lossy compression is most commonlyused to compress multimedia data (audio,video, still images), especially inapplications such as streaming media and

internet telephony. Video can be compressed immensely (e.g.

100:1) with little visible quality loss;

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55..22..55))WhyWhy lossylossy compressioncompression

in streaming mediain streaming media Lossy methods are most often used for

compressing sound, images or videos. This

is because these types of data are

intended for human interpretation wherethe mind can easily "fill in the blanks.

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Internet TV System ArchitectureInternet TV System Architecture

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11. Media Content. Media Content A media content is a video input device

that connects to the encoding station.

A media content suitable for capturing

live broadcasting is: Video card for a PC that connects to a

satellite reciever .

Satellite PC card.

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22. Encoding Station. Encoding Station PC with high storage capacity, memory

and fast processor for reliable capturing.

An encoding software uses a method to

represent and compress video (oftenreferred to as a CODEC) like: RealNetworks: RealProducer Basic (Free)

and Real Producer Pro

Apple: QuickTime Pro (minor cost of $35)Windows Media: Windows Media Tools

(Free)

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33. Content Delivery Servers. Content Delivery Servers Deliver the media stream in one of two

ways: Push: where servers are continuously sent a

stream from the encoder.

Pull: makes a connection and "pulls" thestream when a player connects to it.

Content Delivery Servers could be:

Windows Media Server [Pull] Helix server for RealNetworks [Push]

Darwin Server for QuickTime [Push]

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Thank youThank you

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