International Telecommunication Union
Telecommunication Standardization Workshop25-27 October 2006, Maputo, Mozambique
Multimedia ServicesMultimedia Servicesfrom Narrowband to Broadbandfrom Narrowband to Broadband
Stefano PolidoriAssistant Engineer – ITU-T Study Group 16
“Multimedia Services, Systems and Terminals”
ITU-T
Contents
About ITU-T SG 16Multimedia servicesSummaries: access & media componentsNarrowband services – conferencing and VoIPBroadband services
Additional slides
ITU-T
About ITU-T Study Group 16
ITU-T
ITU-T Study Group 16
Mandate (2005-2008)Responsible for studies relating to:
Capabilities for multimedia services and applications (including those supported for NGN). Definition of Multimedia terminals, systems and protocols (e.g. multipoint conference units, gateways, gatekeepers)Modems and facsimile, evolution towards IPNetwork signal processing equipment Media coding (image, video and speech compression)
Lead Study Group onMultimedia terminals, systems and applications Ubiquitous applications (“e-everything”, such as e-health and e-business)
Lead SG Coordination function
Webpage: www.itu.int/ITU-T/studygroups/com16
ITU-T
SG16 Management Team
Management team:Chairman: Mr P.A. Probst / OFCOMVice-Chairmen:
Mr P. Barrett / Psytechnics (UK)Ms C. Lamblin / FT (F)Mr Y. Naito / Mitsubishi (Japan)Mr I. Sebestyen / Siemens (GER)
Counsellor: Mr Simão CamposAssistant engineer: Mr Stefano PolidoriAdministrative assistant: Ms Isabelle Frost
ITU-T
SG 16 Structure
Study Group 16
“Multimedia Services Systems & Terminals”
Chairman: Pierre-André Probst
Working Party 1
Modem, fax and equipment
transmissionYushi Naito
Working Party 2
MultimediaSystems and
Terminals
I. SebestyenS. Okubo
Working Party 3
Media Coding
P. Barrett C. Lamblin
ITU-TSBCounsellor
SimãoCampos
Q 20 Mediacom&
Q26 Accessibility
ITU-T
SG 16 Working Party 1
WP 1/16 - Modems and facsimile terminals11/16 Voiceband Modems and protocols: Specification and
Performance Evaluation (modems signals evolution across IP Networks)
14/16 Facsimile terminals (Group 3 and Group 4): Specification and Performance Evaluation (Facsimile signals Maintenance and evolution across IP Networks)
15/16 Circuit multiplication equipment and systems 16/16 Speech enhancement in signal processing network
equipment 17/16 Voice gateway equipment definition18/16 Interaction aspects of signal processing network
equipment
ITU-T
SG 16 Working Party 2WP 2/16 - Multimedia systems and terminalsIncluding Legacy systems that we standardized in the past (Conferencing over ISDN, PSTN etc.)
1/16 Multimedia systems, terminals and data conferencing2/16 Real-Time Audio, Video, and Data Communication over
Packet-Switched Networks (evolution of H.323 family Recs)
3/16 Multimedia Gateway Control Architectures and Protocols 4/16 Advanced multimedia communication service features on
top of the ITU-T defined multimedia system platforms5/16 Control of NAT and Firewall Traversal for H.300-Series
Multimedia Systems21/16 Multimedia Architecture22/16 Multimedia applications and services24/16 Quality of Service and End-to-end Performance in
Multimedia Systems25/16 Multimedia Security in NGN (Next-Generation
Networks) (NGN-MM-SEC)28/16 Multimedia framework for e-health applications29/16 Mobility for Multimedia Systems and Services
ITU-T
SG 16 Working Party 3
WP 3/16 – Media coding (4 Qs)6/16 Video coding (Cooperation ISO MPEG group)
9/16 Variable Bit Rate Coding of Speech Signals10/16 Software tools for signal processing standardization
activities and maintenance and extension of existing voice coding standards
23/16 Media coding (coordination across Qs of SG16 and…)
Plenary20/16 Mediacom26/16 Accessibility to Multimedia Systems and Services
ITU-T
Multimedia Services…Concept and Philosophy
ITU-T
Development of MM Applications & Services
Factors:•Users needs•Market Trend•System Design•Architecture•Interoperable
Common Multimedia Parts, e.g.,Coding (G,H,T-series), Security (X-series), Directory (X-series)
Integration or Assembling of
Multimedia Parts(Terminal Design; J,H-Series)
Users
Media (CS, PS, Cable)Wired/Wireless
(ITU and non-ITU)
Recommendations for Applications &Services (F,T series)Interoperability
Numbering,Charging Specs.(E-series)
Performance requirementsBesides guarantee
Quality &Functionality
Basic Architecture
ITU-T
Services in the Multimedia Context
Two paradigms1. Telecommunications perspective2. Broadcasting industry perspectiveTelecoms perspective:
Interactive applications, videoconferencingBroadcasting industry perspective:
Video delivery (e.g. commercial television)
What is happening?Convergence: IT / Telecoms / Broadcasting
Interactive broadcastingTelecom service providers providing entertainment services (entering in entertainment business)
Users view versus technologists view
ITU-T
Where do we come from?
Telephony serviceVoice (including audio-conferencing) ☺Extended services (call waiting, transfer, diversion, hold, pickup, etc SS7-based)
Voiceband data (rather constrained communication channels such as)
“Low” speed data (V-series: V.34, V.90, V.92)“Low” speed Internet accessFax (4.8 – 33.3 kbit/s)Low bit rate multimedia video-conferencing
trial
ITU-T
Where are we going now with Multimedia services
Superset of multimedia servicesThe delivery of one or more than one media need to be Coordinated:
Audiovisual content (fallback to audio-only)Audiovisual plus whiteboard (presentation, document)Delivery of video services (V.o.D. etc.)Duo / triple play: voice / data / video
Capabilities limited by access capacity BUT not all applications need all bandwidth availableClassification of media will help understand viability of different types of aggregation to implement a serviceEvolution: multimedia over narrowband channels to broadband channelsNeed to account for users with disabilities
Total Communication
ITU-T
How hungry an application?
2
1
0.5
Ups
trea
m M
bit/s
0.5 1 2 264Downstream (Mbit/s)
Broadcast & Interactive TV
Voice (PSTN)
Video conferencingInternet access&
Peer-to-peerapplications
e-commerce
Different classes of applications
requirements
requ
irem
ents
ITU-T
MM Service Descriptions
According to the definition of several MM tasks:Conferencing (multipoint, bi-directional, real-time)Conversation (point-to-point, bi-directional, real-time)Distribution (point-to-multipoint, unidirectional)Sending (point-to-point distribution, Tx controlled, UD; info pushing)Receiving (point-to-point distribution, Rx controlled, UD; info retrieval)Collecting (multipoint-to-point distrib., UD, Rx controlled; info polling)
and the association of different Media components:audio, video, text, graphics, data and still-pictureswe associate a certain level of Quality for media components: {-1, 0, 1, 2, 3, 4}
Service definition and requirements are available in the F-series. F.700 contains the umbrella definitions:
Integration of media components from the user’s point-of-view
ITU-T
(e.g.) MM Service Descriptions (2)
F.70x: network-independent definitionsF.702 (F.MCV)-MM conference servicesF.703 (F.MCS)-MM conversational services
Network-specific definitionsF.731- N-ISDN MM conference servicesF.732- B-ISDN MM conference services
This was to give an idea of the overall concept of Service Description
ITU-T
Access components needed to provide MM services:
a brief summary
ITU-T
Access methods
Copper:“Strict” PSTN (dial-up): still the majority use itADSL: up- and down-stream offerings vary depending of the network provider & line conditions. Standard limits on 1.5 Mbit/s (very competitive in market-place)
ADSL+, ADSL2: recent improvements in the techniques, higher bit ratesVDSL: higher bit rates (order of 20 Mbit/s or up)
Fiber:Backbone (traditional)To the curb (dream newer developments)
Wireless:Satellite, microwaveWiFi, WiMax & extensions
ITU-T
Most recent modem standards
V.34, Two-wire PSTN modem for rates of up to 33.6 kbit/s; 1996-10V.90, PSTN modem with digital upstream up to 56 kbit/s andanalogue downstream up to 33.6 kbit/s; 1998-09V.91, Four-wire version of V.90 allowing fully digital up and downstream; 1999-05; 2001-07V.92, Enhancements to Recommendation V.90; Geneva, 2000-11; 2001-07; 2002-03
We have basically reached the limits on this schemes in the bit rates that we can achieve for connecting internet.
only Maintenanceno recent development
ITU-T
ITU-T Recommendations on DSL
G.995.1 – Overview of Digital Subscriber Line (DSL)RecommendationsG.991.1 (HDSL) – High-bit rate Digital Subscriber Line (HDSL) transmission system on metallic local linesG.991.2 (G.SHDSL) – Single-pair High bit rate speed Digital Subscriber LineG.993.1 (G.VDSL) – Very high bit-rate Digital Subscriber LineG.994.1, G.996.1 and G.997.1 for tests, management and handshake
The most popular/successful is ADSL next slide
ITU-T
ITU-T Recommendations on ADSL
G.992.1 (G.DMT) – Asymmetrical Digital Subscriber Line (ADSL) TransceiversG.992.2 (G.LITE) – Splitterless Asymmetrical Digital Subscriber Line (ADSL) TransceiversG.992.3 – Asymmetric digital subscriber line transceivers - 2 (ADSL2.DMT)G.992.4 – Splitterless asymmetric digital subscriber line transceivers - 2 (ADSL2.LITE)
They have become very popularand adopted more and more
ITU-T
1994-2000Single channelTransv compat.Terminal OAs
STM-4 up toSTM-256
G.691
1998Single channelSDHtransv. Compat.
STM-16G.957
1984Single channelPDHLong. Compat.
140 Mbit/sG.955
Date of approval
System defined
Bit rateRecs.
Optical access standards (1)
ITU-T
2002Dense WDM Coarse WDM
≥ 80 Ch/10 Gbit/sUp to 18 Ch/2.5 Gbit/s
G.694.1G.694.2
2001Single channelTransv. Compat.Intra office
10 – 40 Gbit/s(STM-64 to STM-256)
G.693
2000Pre-OTNSingle /WDMTransv Compat.Term. OAsId Interfaces
2.5 and 10 Gbit/s
Up to 16 channels WDM
G.959.1
1996 / 1998WDM 4 to 32 chLong. Compat.Line amplifiersmono/bidirect.
622 Mbit/s – 10 Gbit/s(STM-4 to STM-16)
G.692
Optical access standards (2)
ITU-T
Media components
ITU-T
Data sharing(Data collaboration aspect such as white-boarding, that could
share a presentation, a word file etc. during conferencing)
T.120-T.140,T.17x provide definitions for data exchange and control in MM conferencing applications. For example:
T.120 defines data protocols for multipoint multimedia conferencing (Annex C describes a light version of T.120). E.g. White-board applications. T.140 adds text conversation (“chat” e.g. for hearing-impaired people)T.17x: MHEG for information retrieval
ITU-T
Media Coding
Four aspects:AudioVideoStill-imageOther media coding
ITU-T
Media Coding: Audio
Three “classic” quality tiers: audio (20khz), wideband (7khz) speech, and telephony (4khz) speech. (Super wideband arrive to 14khz)
ITU-T focus on interactive communications as opposed to broadcasting communications, hence mainly produced wideband and telephony speech compression standards (F.700’s A0 and A1 Quality Levels).
Interactive communication signals requirements are different than broadcasting signal requirements(e.g in terms of delay, quality and complexity)
ITU-T
Media Coding: A2/A3 Audio
The higher tiers of quality are A2 and A3 according to F.700 terminology.
In ITU-T the A2 coding for broadcast applications is standardized in J.41 (logarithmic PCM compression, 15kHz, 384kb/s) 1988 (very simple compression scheme)
In the A2 and A3 audio coding arena we have the very famous ISO MPEG compression schemes
A2&A3 Audio coding: ISO MPEGMPEG2/Audio (e.g. MP3)MPEG4/Audio
ITU-T
Media Coding: A1 Audio
A1: Wideband speech coders (50-7000Hz)J.42 11-bit logarithmic PCM compression (192 kbit/s) 1988G.722 Split-band ADPCM Coding of 7 kHz speech (64,56&48 kbit/s) 1988 [older standard used in particular for ISDN conferencing applications]
G.722.1 Transform coding (32&24 kbit/s) 1999
Extension to 14 kHz Bandwidth (2006) A2 Audio
G.722.2 Coding of 7 kHz speech at around 16 kbit/s (5.5-24 kbit/s) 2002 (developed with the 3GPP)
G.729.1 Embedded wideband extension of G.7292006
ITU-T
Media Coding: A0 Audio Telephony speech coders (300-3400 Hz)
Concerning the telephony band quality tier, A0 according to the F.700 definition, we have the very famous G.711 PCM developed in late 60’s and approved in 72 (64 kbit/s)
G.726 ADPCM coding (32; 40, 24 & 16 kbit/s) 1988G.727 Embedded ADPCM coding (40-16 kbit/s) 1990G.728 LD-CELP coding (16; 40, 11.8 &9.6 kbit/s) 1992G.723.1 Dual-rate coding (5.3 & 6.3 kbit/s) 1995G.729 CS-ACELP coding (8; 12.8 & 6.4 kbit/s) 1996G.VBR Variable bitrate speech coding
Ongoing!
ITU-T
Media Coding: Video
ITU was a pioneer in video coding standards with the dev elopment20 years ago H.261 → Video Codec for N-ISDN
15 years ago H.262 = with ISO (MPEG2/Video) (“Common text”) used in broadcasting and DVDLate 90’s H.263 and Annexes → is mainly a conversational video coding standard used for videoconferencing over IP, wireless, and N-ISDNRecently H.264: successor to H.262 in entertainment applications (soon we will see it in NG-DVD player), and successor of H.263 in conferencing and 3G-mobile applicationsH.264 is seen as a success in the market, also some broadcaster for digital terrestrial adopted it and was voted recently as one of the best ITU-T standards
ITU-T
Comparison to MPEGComparison to MPEG--2, H.263, MPEG2, H.263, MPEG--4 for videoconferencing4 for videoconferencing
27282930313233343536373839
0 50 100 150 200 250
Foreman QCIF 10Hz
QualityY-PSNR
` [dB]
MPEG-2H.263
MPEG-4H.264/AVT
Comparison of H.264 to other standards low bit-rate (video conferencing)
Bit-rate [kbit/s]
[dB]
ITU-T
Comparison to MPEGComparison to MPEG--2, H.263, MPEG2, H.263, MPEG--4 for digital TV quality4 for digital TV quality
Tempete CIF 30Hz
2526272829303132333435363738
0 500 1000 1500 2000 2500 3000 3500Bit-rate [kbit/s]
QualityY-PSNR [dB]
MPEG-2H.263
MPEG-4H.264/AVT
Comparison of H.264 to other standards DTV Digital TV
Will be used in IPTV where, to provide many channels, saving in bandwidth is envisaged
ITU-T
Media Coding: Still Image
Standards work performed by a “Collaborative ITU|ISO/IEC Team”working under ISO/IEC SC29 rules and organization
Still image (B/W & color) is used infacsimile services, in Internet applications, digital photography, etc.
ITU has “common-text” for JPEG/JBIG (T.80 series) and JPEG2000 (T.800 series)
ITU-T
Other media coding
Currently not performed in ITU-T:
Speech synthesis (text-to-speech)Speech recognition (new developments)
ITU-T
Narrowband multimedia services:
Conferencing including VoIP
ITU-T
Development of MM Applications & Services
Factors:•Users needs•Market Trend•System Design•Architecture•Interoperable
Common Multimedia Parts, e.g.,Coding (G,H,T-series), Security (X-series), Directory (X-series)
Integration or Assembling of
Multimedia Parts(Terminal Design; J,H-Series)
Users
Media (CS, PS, Cable)Wired/Wireless
(ITU and non-ITU)
Recommendations for Applications &Services (F,T series)Interoperability
Numbering,Charging Specs.(E-series)
Performance requirementsBesides guarantee
Quality &Functionality
Basic Architecture
ITU-T
Multimedia terminals & systems
H.324: Communications using circuit-switched services [fixed (PSTN) and mobile (3GPP)] H.320: Communications over N-ISDN ☺H.310: Communications over B-ISDN H.323: Communication conferencing system over packet networks (mainly IP, mainly voice) ☺This is a system of recommendations that provide a packet of solutions to implement a conferencing systems:
H.450.x: Supplementary services for H.323 systemsH.246: Multimedia Terminal InterworkingH.248[.x]: Interworking between H.323 packet-based networks and the PSTNH.235: Security for H.323 systems…
Conferencing over different networks
ITU-T
Interoperability amongst MM terminals
H.324 H.310
H.320H.323
Audio/Video
User data
User data
User data
User data
Audio/Video
Audio/Video
Audio/Video
Mux
QoS
RTP/Non-QoS
H.223
H.225.0
H.222.0H.222.1
H.221
Call Control (H.245)
Call Control (H.242/H.243)
Call Control (H.245)
Call Control (H.245)
H.223 Anx.A-D
Fixed
Mob
ile
Scope for H.246
ITU-T
Narrowband multimedia services:
Conferencing including VoIP
ITU-T
VoIP
Special case of the videoconferencing problem space
Monomedia voicePlus services: call transfer, call waiting, call forward
ITU-T H.323 SystemCreated in the mid 1990’s to emulate over packet networks the successful H.320 videoconferencing standard used in ISDNEvolved to become the most widely used complete protocol for VoIP conferencing
ITU-T
ITU-T Recommendation H.323 (1/2)
H.323 describes terminals and other entities that provide multimedia communications services over packet based networks which may notprovide a guaranteed Quality of Service.
H.323 is mostly used over IP networks, in particular for voice services VoIP
H.323 architecture is based on intelligent call control and relatively "dumb" endpoints – similar to the PSTN design
Central control, highly managed
Those entities may provide real-time audio, video and/or datacommunications. Support for audio is mandatory, while data and video are optional, but if supported interworking is required.
Packet based network may comprise: a point-to-point connection, a single network segment, or more complex topologies where several networks or domains are involved
Reason why H.323 is widely deploid for VoIP
ITU-T
ITU-T Recommendation H.323 (2/2)
H.323 entities may be used in point-to-point, multipoint or broadcast (ITU-T H.332) configurations
Thanks to the use of gateways they may interwork with:H.310 and H.321 terminals on B-ISDN, H.320 terminals on N-ISDN, H.324 terminals on GSTN and 3G networks,
H.323 entities can be integrated into personal computers or be stand-alone devices (e.g. videotelephones)
The protocol can be modularly extended for extra features(H.450.x and H.460.x sub-series), e.g.
Call priority schemes (emergency situations)Message broadcast (applicable to early warning delivery)Supplementary servicesNAT and firewall control and traversal
ITU-T
SIP
IETF SIP (Session Initiation Protocol) is a signalling protocol described in RFC 3261
establish, change, and terminate callsdoes not deal with media content of the calldoes not deal with session description
Needs other protocols to implement specific solutions
Flexibility in defining services, e.g. a videoconferencing solutionInteroperability of services may be an issue
Intelligence delegated to the endpoints
ITU-T
SIP and H.323
SIP is only a signalling protocol, while H.323 provides an integrated solutionSIP delegates the complexity to the endpoints, while H.323 allows for simple terminals and allocate the “intelligence”to the networkH.323 is an integrated solution, while SIP is open ended (other protocols need to be added to implement solutions)
ITU-T
BroadbandMultimedia Services
ITU-T
Two broadband perspectives
1. Broadcasting perspective:What is happening?
convergence from broadcasting perspective:
IP Cablecom Architecture
2. Telecom perspective What is happening?
convergence from telecom perspectiveFull-service VDSL ArchitectureIPTV
ITU-T
Broadband MM over cable: ITU-T Cablecom
Project managed by ITU-T Study Group 9IP Cablecom refers to standards for IP cablecommunicationsIP Cablecom defines architecture and interface specificationsIt builds on J.83 / J.112 cable modem transport Initial market driver for IP Cablecom has been IP telephonyFlexibility for cable providers to offer new services market deregulations
ITU-T
Some applications for ITU-T Cablecom
Residential/Business IP TelephonyVoice over IPVideo IP telephonyVoice/data/video unified messagingEnhanced conferencing and media servicesEntertainment Services
Real-time multiplayer interactive gaming
ITU-T
IP Cablecom architecture
AN Access NodeCM Cable ModemHFC Hybrid Fiber Coax NetworkMTA Multimedia Terminal AdapterPSTN Public Switched Tel. Network
Embedded MTA
PSTN
PSTNGateway
CallManagement
Servers
CMMTA
Back OfficeServers
Managed IPNetwork
AN
CMHFC
ITU-T
IPCablecom Recs for interoperability intra-zone and with PSTN
ArchitectureJ.160 Architecture
SignalingJ.162 Network Call SignalingJ.165 IPCablecom SignalingJ.171 Trunk Gateway Control Protocol
Quality of ServiceJ.163 Dynamic QoS
Media/CodecsJ.161 Audio Codec Reqs.
Operating Support SystemJ.164 Event MessagingJ.166 MIB FrameworkJ.167 MTA ProvisioningJ.168 MTA MIBJ.169 NCS MIB
SecurityJ.170 Security
ITU-T
IPCablecom Recs. for interoperabilityinterzone and inter-domain directly
over managed IP backbones
Quality of ServiceJ.174 Inter-domain QoS
SecurityJ.170 Security
ArchitectureFor further study
SignalingFor further study
Operating Support SystemJ.164 Event Messaging
ITU-T
Broadband MM over the local loop:Full service VDSL specifications
Work under the FS-VDSL Focus Group (whose parent Study Group is SG 16)Video-centric services using the local loopOpportunity for network operators to compete with Cable network providersNot ITU-T Recommendations (yet)Assumes high rate availability at customer’s premises: combination of fiber & VDSLCurrent architecture is ATM-based (PPPoA), IP extensions foreseen (PPPoE)
Evolution: IPTV
ITU-T
FS-VDSL Architecture
Digital Broadcast Network
Interactive A/V
Network
Internet Service Provider
Voice Services
(IP, PSTN)
VDSL
Voice Services
(PSTN/ISDN) Digital Customer PremiseDistribution Network
Video onDemand
Broadcast TV
InternetServices
User premises
Local Loop &
Transmission Multiplexing & Delivery over optical
ITU-T
Full Service VDSL Technical Specifications
Focus Group Technical Specification(http://www.itu.int/ITU-T/studygroups/com16/fs-vdsl)
Part 1: Operator requirements Part 2: System ArchitecturePart 3: Customer Premises EquipmentPart 4: Physical Layer Specification for Interoperable VDSL SystemsPart 5: OAM&P aspects for FS-VDSL Services
H.610
H.611
ITU-T
IPTV
Evolution of the concept for distribution of content by network operators
ATM PHY to IPIP offers more flexibility / opportunities beyond the fixed network
Generalized architectureChallenges for QoS, media coding, digital rights management, bandwidthHuge interest of operators, industry and regulators
IPTV is covered in detail in a separate presentation
ITU-T
Conclusions
Network / infrastructure evolution will allow introduction of richer servicesConvergence of services and applications from IT, Telecom & Broadcasting industries is coming!Services that can be introduced are a function of the bandwidth available: taxonomy of the applications is neededEvolution:
monomedia, narrowband services to multimedia, narrowband to multimedia, broadband
ITU-T
Thank you for your attention!
For further contact, please feel free to contact:Simão Ferraz de Campos NetoCounsellor, ITU-T Study Group 16
[email protected]: +41-22-730-6805Fax: +41-22-730-5853
http://www.itu.int/ITU-TOr
Stefano PolidoriAssistant Engineer, ITU-T SG 16
[email protected]: +41-22-730-5858Fax: +41-22-730-5853
ITU-T
AdditionalSlides
ITU-TFunctional model for H.324 Terminal
NetworkInterface
Audio Coding (e.g. G.723.1)
Video Coding (e.g. H.261, H.263)
Data Coding (T.120; V.14, LAPM)
System Control (H.245,SRP/LAPM)
Call Control (National standards; V.250)
MM Mux & Sync(Fixed network: H.223;
Mobile: H.223 Annexes A-D)User
Interface
PSTN multimedia terminals
• Will not scale towards bandwidth-hungry applications due to basic limitation of the network capacity
• Conferencing-centric
ITU-T
ISDN multimedia terminals
Functional model for H.320 N-ISDN Terminal
NetworkInterface
Video Coding (H.261)
Audio Coding (G.711)
System Control (H.242)
Call Control (Q.931)
MM Mux& Sync(H.221)
Data Coding (T.120)User
Interface
• Will not economically scale towards bandwidth-hungry applications
• Conferencing-centric
ITU-T
Functional model for H.323 Terminal
NetworkInterface
Audio Coding (e.g. G.711, G.729)
Video Coding (e.g. H.261, H.263)
User Data Coding (T.120)
System Control (H.245)
Call Control (H.225.0, Q.931)
MM Mux& Sync
(H.225.0)
UserInterface
Packet-based MM terminals
• Scales well towards bandwidth-hungry applications, depending on capacity of the underlying networks
• Conferencing-centric
ITU-T One of the main goals of the MediaCom Project is to reduce need for higher layer Gateway
functionality
Mobile NetworkIP NetworkCS Network
Telephony, FAX,VPS/VCS, Webcasting,
Multimedia
Telephony, FAX,VPS/VCS, Webcasting,
Multimedia
Gateway Gateway
Q20 MediaCom: Goal
ITU-T
Modem-over-IP context
IP Network
Gateway
Telephone
Modem
Fax
Fax
Modem
1 2 3
4 5 67 8 9
* 8 #
VoIP terminal
Modem Bank
Server Modems
SD
Central Office
S D
Central Office
Gateway
ITU-T Rec V.150.1 – Procedures for the end-to- end connection of V-series DCEs over IP-networks
ITU-T
H.323 backgroundThe most popular and extensible early compressed videoconferencing was enabled via the ITU standard called H.320, describing videoconferencing services over ISDN and T1 leased and dedicated telephone lines. H.323 was designed early in 1996 to both function like and interoperate with H.320, changing the transport layer only so that the protocol would work on the Internet. H.323 architecture is based on intelligent call control and relatively "dumb" endpoints – similar to the PSTN design
Central control, highly managedH.323 is an umbrella standard consisting of several different protocolsSignaling and call control H.225.0 (Q.931) + H.245. Flexible support of audio and video codecs
Standard: G.711, G.729, G.723.1; H.261, H.263, H.264 …Non-standard (bilaterally agreed by terminals)
Security features defined in the H.235 sub-seriesOnce call control completes, the media transfer can begin by using the IETF Real Time Protocol (RTP).
ITU-T
H.235 - “H.323 Security”Security Protocol Architecture
AV Applications
Audio
G.711G.722G.723.1G.729
Video
H.261H.263
Encryption
RTCP
H.225.0Terminal
to Gatekeeper
Signaling
(RAS)
Terminal Control and Management DataApplications
SecurityCapabilities
SecurityCapabilities
T.124
T.125
Unreliable Transport / UDP, IPX Reliable Transport / TCP, SPX
Network Layer / IP / IPSec
Link Layer /......
Physical Layer / .....
T.123
Scope of H.323 Scope of H.235
TLS/SSL
Multimedia Applications, User Interface
TLS/SSL
Authenti-cationRTP
Scope of T.120
H.225.0Call
Signaling(Q.931)
H.245SystemControl
ITU-T
Information on SIPThe IETF Session Initiation Protocol (SIP) is described in RFC 3261SIP was created in the mid 90's to invite people to view an IP multicast session (e.g. a lecture) on the M-Bone (an early academic experiment on what we call today “webcasting”)
SIP is simply a signaling protocol used to establish, change, and terminate calls between one or more users in an IP network, without dealing with the media content of the call
SIP moves application control to the endpoint, eliminating the need for intelligence in the network core
Philosophy similar to TCP/IP’s and of other Internet protocols, where management control is pushed as much as possible to the endpoints
SIP is not an all-in-one solution, as it does not handle media transfer, resource reservation, or session description.
SIP needs to be used in conjunction with other protocols to implement specific solutions.
Flexibility in defining services, e.g. a videoconferencing solutionInteroperability of services may be an issue
Typically:RTP (RFC 3550) may be used for media transfer (as in H.323) SDP (RFC 4566) is used for session descriptionOther specifications are needed for services: VoIP, conferencing, etc (no RFC yet in place)
ITU-T
Media CodingSupplemental Slides
ITU-T
Telephony-band Speech Coding Families
Channel
Formant
Homomorphic
LPC
MBE
Parametric(Vocoding)
WaveformCoding
PCM
DPCM
ADPCM
DM
ADM
CSVD
HybridCoding
APC
RELP
MPLPC
CELP
SELP
SBC
ATC
Sinusoidal
Harmonic
Phase
ITU-T
Telephony-band Speech Coding Families
1 2 4 8 16 32 64
Vocoding
Waveform Coding
Hybrid Coding
LPC10e
MBE
CELP
APCMPLPC
ATCRELP
DPCMADPCM
LogPCMQuality
Bit rate (kbit/s)
ITU-T
A2/A3 Non-ITU Standards
MPEG2/Audio: audio coding > 64 kbit/s (1992)MPEG4/Audio: audio + speech coding at bit rates between 64 and 2 kbit/s (1998)
ITU-T
A0-A1 Non-ITU Standards
ETSI/3GPP:13 kbit/s RPE-LTP (Full rate GSM, 1988)6.5 kbit/s VSELP (Half-rate GSM, 1993)12.2 kbit/s EFR (Enhanced full-rate GSM, 1996)12.2 - 4.75 kbit/s AMR (Adaptive Multi Rate, 1999)6.6 - 23.85 kbit/s AMR-WB (Wideband AMR, 2001)AMR-WB+ ongoing work
ARIB (Japan):Full-rate PDC (Personal Digital Communication) 6.7 kbit/s VSELPHalf-rate PDC 3.45 kbit/s Pitch Synchronous Innovation CELP
ITU-T
A0-A1 Non-ITU Standards (cont’d)
US TIA (ANSI)CDMA / 3GPP2
IS96 8,4,2 kbit/s QCELP (Qualcomm CELP, 1992)IS127 8.55, 4, 0.8 kbit/s EVRC (Enhanced Var. Rate Codec, 1996)IS733 13.3, 6.2, 2.7, 1 kbit/s VRC (Variable Rate Codec, 1998)CDMA2000 9.6,4,2.4,0.8 kbit/s SMV (Selectable Mode Vocoder, SMV, 2002)Wideband SMV
TDMAIS54 7.95 kbit/s VSELP (Vector-Sum Excitation Lin.Pred., 1990)IS641 7.4 kbit/s ACELP (Algebraic CELP, 1997)
PCS1800 (GSM upbanded to 1800 MHz)IS136-410 12.2 kbit/s US1 (1999)
ITU-T
Still Image Coding Summary (1)
Umbrella: T.80 [1992]
JPEG: T.81 (Part I), lossy and loss-less [1992]; T.83 (Compliance testing) [1994]; T.85 (Extensions, defs & testing) [1996]; T.85 Corr.1 [1999]; T.86 Registration of JPEG Profiles [1998]; T.87 (Baseline) Lossless and near-lossless compression of continuous-tone still images [1998]; T.851 (JPEG1-based still-image coding using an alternative arithmetic coder)
JBIG: T.82, loss-less [1993]; T.82 Corr.1 [1995]; T.85 JBIG for fax terminals; T.85 Amd.1 [1996], 2 [1997]; T.85 Corr.1 [1997]; T.88 Lossy/lossless coding of bi-level images [2000]; T.89 Application profiles for Recommendation T.88 [2000]
ITU-T
Still Image Coding Summary (2)
JPEG 2000: T.800: Part 1, JPEG 2000 Image Coding System: Core Coding SystemT.801: Part 2, JPEG 2000 Image Coding System: ExtensionsT.802: Part 3, Motion JPEG 2000T.803: Part 4, Conformance TestingT.804: Part 5, Reference SoftwareT.807: Part 8, Secure JPEG 2000T.808: Part 9, Interactivity tools, APIs and protocolsT.810: Part 11, Wireless
ITU-T
ITU-T Video Coding
H.261: Video Codec for A/V services at p x 64 kbit/sThe first practical video coding standard (1990)Used today in (ISDN) video conferencing systemsBit rates commonly 40 kbit/s to 2 Mbit/s
H.262: Same as MPEG-2/Video (ISO/IEC 13818-2)Commonly used for entertainment-quality video applicationsThe first practical standard for interlaced videoUsed in digital cable, digital broadcast, satellite, DVD, etc.Bit rates commonly 4-20 Mbit/s
H.264: Advanced video coding for audiovisual servicesCommonly developed with MPEG ( MPEG4 Part 10)Widely adopted for broadcast, entertainment and visual communication (including 3G) applicationsBit rates at least half of H.262 | MPEG2/Video and H.263 (depending on the application) for the same level of quality
ITU-T
ITU-T Video Coding(continued)
H.263: Video Coding for Low Bit Rate Communication
Significantly improved video coding compression performance (especially at very low rates, but also at higher rates as well)The first error and packet loss resilient video coding standardUsed in Internet protocol, wireless, and ISDN video conferencing terminals (H.323, H.324, 3GPP, etc.)“Baseline” core mode interoperable with MPEG-4/VideoRich set of features for many applicationsVery wide range of bit rates and possible applications
ITU-T
Non-ITU-T Video Coding
MPEG-1/Video (ISO/IEC 11172-2)The first video coding standard using half-pelmotion compensationTypical bit rates 1-2 Mbits/s
MPEG-4/Visual (ISO/IEC 14496-2) [DivX]The first video coding standard defining arbitrary object shapesMany creative features for synthetic and synthetic-natural hybrid contentContains essentially all features of all prior standard codec designsInteroperable with ITU-T H.263 “baseline”Very wide range of bit rates and possible applications
