Evolution of Mobile Video Delivery in the US
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Transcript of Evolution of Mobile Video Delivery in the US
Evolution of Mobile Video Delivery in the USJeff Van DykeDirector of TechnologyOffice of the CTODialogic, Inc.
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Agenda
• Video Quality Factors• Characteristics of Video Services• Video Delivery Methods
– 3G-324M– Video over IP– Broadcast Video
• Where are We Headed?
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Video Quality Factors• Video quality is determined by:
– Display resolution and size– Codec and level of compression– Frame rate– Network quality of service (QOS)
• Given a specific codec improving the video quality requires more network bandwidth and better QOS
• High quality video delivery requires high bandwidth and high QOS from the network.
– None of today’s networks were originally designed for video• PSTN – low bandwidth, high QOS for voice• Cellular – low bandwidth, low/medium QOS for voice and low bit rate
data (SMS)• Internet – medium bandwidth, low inherent QOS for telnet, SMTP and
FTP
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Display Considerations• Common screen resolutions
• What can today’s devices support?
– iPhone - 480 x 320 pixels– LG Dare - 400 x 240 pixels
• Standard YouTube videos are QVGA scaled to 480 x 360 pixels
Size Width Height
QCIF 176 144
QVGA 320 240
CIF 352 288
VGA 640 480
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Frame Rate
• The perception of smooth motion requires approximately 18 frames per second
– In practice mobile video is delivered at 10 – 15 FPS
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Characteristics of Video Services• Interactive communication (e.g. video call)
– Low complexity– Usually small display sizes (QCIF) with low frame rates (~10)– Compared by users to dedicated video phones or soft phones– Lowest user expectations for quality– Camera placement on handsets is problematic for this application– Bandwidth: < 64 Kb/s
• User and content provider generated streaming video (e.g. YouTube)– Low to medium complexity– Larger display sizes (CIF or QVGA) and medium frame rates (15 – 20)– User expectation set by YouTube and similar sites– Bandwidth: 128 Kb/s – 300 Kb/s
• Entertainment video (e.g. broadcast TV shows)– Medium to high complexity (e.g. sports broadcasts)– Larger displays (>= CIF and QVGA) and high frame rates (>= 20)– High user expectation based on movie and TV viewing– Bandwidth: > 300 Kb/s
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Video Delivery - 3G-324M
• Multiplex of control, audio and video in a single 64 Kb/s channel
– Video bandwidth limited to about 45 Kb/s
• Advantages– Proven, deployed technology– Low, deterministic transport delay– Infrastructure available
• Disadvantages– Limited bandwidth makes it difficult to deliver a
compelling user experience
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3G-324M Protocol Diagram3G-324M protocol(3G TS 26.111)
3G-324M protocol(3G TS 26.111)
CCSRL
Video Codec:
H.263MPEG-4H.264
H.245Call Control
NetworkInterface
Audio Codec:
AMR-NB*G.723.1
AMR-WB*
Data Codec
V.14LAPM
H.223Multiplexer/
Demultiplexer
H.223 Annex AH.223 Annex BH.223 Annex CH.223 Annex D
NSRP
Video I/OEquipment
SystemControl
Audio I/OEquipment
User Data
Call Control (via ISUP, ISDN, BICC)--3G TS 26.112--
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Video Delivery - IP• Purely packet based
– Call control via SIP– Media transport via RTP
• Advantages– Sufficient bandwidth for delivering video that meets user
expectations– Flexibility to support various video services
• Disadvantages– Infrastructure issues
• IMS networks not fully in place• Quality of service for video transport• IP address limitations (IPv4 vs. IPv6)• Confusion and competition among transport technologies (e.g. HSPA,
WIMAX, LTE)
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Video Delivery - Broadcast• Separate network for broadcast TV content
– MediaFLO, DVB-H
• Advantages– Doesn’t saturate current voice/data spectrum with video– Can deliver good quality (high frame rates and good QOS)
• Disadvantages– Completely separate infrastructure– Can’t be used for interactive communications or user generated
web content
• Do mobile users really want broadcast content?– Streaming model gives users more control and flexibility
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Where are We Heading?• 3G-324M not sufficient to deliver rich video services• Video over IP breaks through the bandwidth limitation of 3G-
324M but:– There are technical issues (e.g. QOS)– There are economic issues (e.g. infrastructure costs)– There are many transport alternatives currently in competition with
each other (e.g. HSPA, WIMAX, LTE)
• Lots of noise around broadcast TV but will consumers want it?
• Opinion: Video over IP will win eventually but it will be a bumpy ride
– “May you live in interesting times.” – reputed ancient Chinese curse