Jan 01, 2016
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Agenda
• Market drivers and devices• Applications• Compression• 3G-324M• Gateways and content adaptation
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3G devices
• By the end of February 2007 there were 444 million paying subscribers on 3G networks in 35 countries
• Take up is faster than 2G was
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Video on mobiles
• By 2010 there will be 102 million mobile video subscribers worldwide – In-Stat
• Worldwide revenues from P2P video calls will reach $6.1 billion by 2009 – Ovum
• Revenue from mobile video and mobile TV applications will reach nearly $2 billion in Europe by 2009 - IDC
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Applications
“See what I see”
Video chatVideo
conferencing
Conversational
Video ring tones
Games
Video clips
Videomail
IVVRIPTV
Video on demand
Pay-per-view
Content
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Do we need to compress?
Uncompressed video :
Height 483 linesWidth x 720 pixelsFrame rate x 30 fpsColour x 20 bits/pixelFrame overhead x 1.3
== 270Mbps
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Compression
QCIF video :
Height 144 linesWidth x 176 pixelsFrame rate x 30 fpsColour x 20 bits/pixelFrame overhead x 1.3
== 20Mbps
Frame rate x 15 fps== 10Mbps
Colour x 16 bits/pixel== 8Mbps
Resolution Size
SQCIF 128 x 96
QCIF 176 x144
CIF 352 x 288
VGA 640 x 480
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Compression
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Most videos have little motion between frames.We can subtract the previous frame from the current and only encode the differences (which even with ‘fast moving action’ tend to be small)
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Compression
• 3 types of frame – I, P, B– Intra-coded
• Compressed version of the frame itself
– Predictive coded• Look for a (16x16) macroblock that best matches the one being
coded and generate a motion vector
– Bi-directionally predictive coded• As above but uses both preceeding and following frames
• Typically IBBPBBPBBPBBI (a GOP)
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Compression
QCIF video :
Height 144 linesWidth x 176 pixelsFrame rate x 7.5 fpsColour x 0.2 bits/pixelFrame overhead x 1.2
== 45kbps
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Bringing it together – 3G-324M
• 3G-324M is the umbrella protocol which covers audio, video, and their transmission
• ITU H.324M adopted by 3GPP• Requires 64 kbps circuit-switched bi-directional data
channel– Provided by the PSTN, so video calls from mobile to mobile
can traverse the PSTN
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3G-324M H.223
• H.223 multiplexes outbound video, audio, data and control streams into a single bit stream suitable for transmission down a 64 kbps constant bit-rate pipe, and de-multipelxes the inbound stream into the relevant media stream.
• Also performs framing, sequence numbering and error detection/correction
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3G-324M H.245
• H.245 is the control channel; it provides for terminal capability exchange and media channel management
• H.245 also used by H.323
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3G-324M
• As a technology 3G-324M presents the following benefits– Guaranteed quality of service– Easy to use– Standard revenue collection approach– Simple to deploy
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Content adaptation
Transcoding
Frame size conversion Qcif, cif, D1
Frame rate conversion 5fps to 30fps
According to bandwidthBit rate adaptation
Coding syntax conversion H.263, H.264, MPEG4
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Content adaptationMulti-screen video
conferencing
Text and logo insertion