Video conferencing
 •   Introduction
 •   Standards
 •   Products
 •   Internet telephony
 •   Computer Telephony Integrat...
Introduction
 • Video conferencing can be used for
     + Audio-visual communication
     + Sharing of documents, tables, ...
Systems
 • Two main types:
     + Video conferencing rooms
     + Video conferencing software
 • Video conferencing rooms ...
Equipment

      Video/audio   Modem, ISDN
        capture       or LAN
                                  Communication
  ...
Group Meetings
 • Two types of video conferences:
     + Point-to-point conferences (video telephony)
     + Multipoint co...
Multipoint Conferences


                 Communications
                    network




                 Multipoint serve...
Standard Families
 • Integrated Services Digital Network - ISDN
   (H.320)
 • Networks supporting QoS (H.310, H.321, and
 ...
Standard families (cont.)




Petri Vuorimaa                  8
H.320




Petri Vuorimaa   10
Video
 • Two resolutions:
     + Quarter Common Intermediate Format (QCIF): 176 x
       144
     + Common Intermediate Fo...
Audio codecs
 • Three different audio codecs:
     + G.711 48-64 Kbps narrow band
     + G.722 48-64 Kbps wide band
     +...
Different classes




Petri Vuorimaa          13
H.324




Petri Vuorimaa   14
H.324
 • Meant for Plain Old Telephone Systems (POTS)
 • H.263 can be used for below 64 Kbps video
   coding
     + sub-QC...
H.324 (cont.)
 • Can use even 28.8 and 33.3 Kbps modems (V.34)
 • Codecs are better, but quality is worse than H.320
     ...
H.323




Petri Vuorimaa   17
H.323
 • LANs (Internet & Intranet) without QoS support
 • Clients, multipoint servers, gateways and
   gatekeepers
 • Rea...
Gateway
 • The gateway allows the integration of H.323
   networks with other networks
 • Tasks:
     + transformations be...
Gatekeeper
 • Gatekeeper takes care of resource reservations
 • The amount of simultaneous users can be limited
 • Transfo...
Multipoint Server
 • Required when three or more clients participate
   the conference
 • Is composed of two parts:
     +...
Multipoint Server (cont.)
 • Videoconferences can be set up in three different
   ways:
     + unicast, multicast, and bro...
Different alternatives




Petri Vuorimaa               24
Protocol stack




Petri Vuorimaa       25
T.120
 • Implements the extra services:
     + conformance
     + image transfer
     + shared workspaces
     + file tran...
T.120 (cont.)
 • T.120 is composed of three layers:
     + transport layer
     + protocol layer
     + application layer
...
Transport layer




Petri Vuorimaa        28
T.120 (cont.)
 • Protocol layer is composed of
     + image transfer (T.126)
     + binary file transfer (T.127)
     + sh...
Products
 •   Video conference bridges
 •   Video networks
 •   Video conference rooms
 •   Workstations
 •   Gatekeepers
...
Video conference bridges
 • Support primarily H.320 and T.120 standard
   families
 • Allow multipoint video conferencing
...
Video networks
 • Best possible image quality
 • Intended primarily for conferences
 • Uses either ISDN or ATM network



...
Video conference rooms
 •   Intended for video conferencing
 •   Maintained by companies or operators
 •   Based on H.320 ...
Workstations
 • LAN, ISDN, or modem card
 • Audio and video cards
 • Software (e.g., Microsoft Netmeeting, Picturetel,
   ...
Gatekeepers
 • Required by H.323 standard family
 • For example, Intel LANDesk Conferencing
   Manager
     + automatic ga...
Gateways
 • Intel LiveGateway
     + bi-directional connection between H.323 and H.320
       systems
     + format transf...
Internet telephony
 • With suitable hardware and software computers
   connected to Internet can be used for telephony
 • ...
Internet telephony (cont.)




Petri Vuorimaa                   38
Internet telephony (cont.)
 • Some long distance operators use Internet
   connections for telephony
 • Allows the use of ...
Calls within organization




Petri Vuorimaa                  40
Public Internet calls




Petri Vuorimaa              41
Internet telephony products
 • Microsoft Netmeeting supports H.323 and T.120
   standard families
 • Includes H.263 video ...
CTI
 • Computer Telephony Integration (CTI) integrated
   computers and telephones
 • Brings savings and increases efficie...
CTI block diagram




Petri Vuorimaa          44
CTI applications
 • Voice mail (answering service)
 • Automatic call transfer
 • Intelligent call routing and distribution...
CTI applications (cont.)
 • Interactive telephone services (reservations,
   orders, etc.)
 • Call records (automatic reco...
CTI implementations
 • CTI can be based on separate server
 • Another alternative is to join telephone directly to
   work...
Call Center




Petri Vuorimaa    48
Integrated system




Petri Vuorimaa          49
CTI standards
 •   Multi-Vendor Integration Protocol (MVIP)
 •   System Computing System Architecture (SCSA)
 •   Both are...
PC cards




Petri Vuorimaa   51
CTI APIs
 • Microsoft Telephony Application Programming
   Interface = TAPI (-93)
     + Windows applications
 • Novell Te...
CTI APIs (cont.)
 • SCSA framework
 • Sun Java Telephony API = JTAPI
     + Java-framework
     + utilizes above mentioned...
Video conferencing
Video conferencing
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Video conferencing

  1. 1. Video conferencing • Introduction • Standards • Products • Internet telephony • Computer Telephony Integration (CTI) Petri Vuorimaa 1
  2. 2. Introduction • Video conferencing can be used for + Audio-visual communication + Sharing of documents, tables, pictures, etc. • Several benefits + Traveling costs + Response time + Better understanding (body language) Petri Vuorimaa 2
  3. 3. Systems • Two main types: + Video conferencing rooms + Video conferencing software • Video conferencing rooms are for group meetings + Organization either has it own premises or rents them from operator • Video conferencing software is for personal use Petri Vuorimaa 3
  4. 4. Equipment Video/audio Modem, ISDN capture or LAN Communication network Audio card Petri Vuorimaa 4
  5. 5. Group Meetings • Two types of video conferences: + Point-to-point conferences (video telephony) + Multipoint conferences (group meetings) • In group meetings, there are two ways to share turns (i.e., floor control): + Automatic selection (e.g., based on audio) + Chairman Petri Vuorimaa 5
  6. 6. Multipoint Conferences Communications network Multipoint server Petri Vuorimaa 6
  7. 7. Standard Families • Integrated Services Digital Network - ISDN (H.320) • Networks supporting QoS (H.310, H.321, and H.322) • Local area networks - LAN (H.323) • Plain old telephone systems - POTS (H.324) • Shared workspaces (T.120) Petri Vuorimaa 7
  8. 8. Standard families (cont.) Petri Vuorimaa 8
  9. 9. H.320 Petri Vuorimaa 10
  10. 10. Video • Two resolutions: + Quarter Common Intermediate Format (QCIF): 176 x 144 + Common Intermediate Format (CIF): 352 x 288 • Frame rates 7.5, 10, 15, or 30 frames per second • Motion estimation can be used, but is not necessary Petri Vuorimaa 11
  11. 11. Audio codecs • Three different audio codecs: + G.711 48-64 Kbps narrow band + G.722 48-64 Kbps wide band + G.728 16 Kbps narrow band Petri Vuorimaa 12
  12. 12. Different classes Petri Vuorimaa 13
  13. 13. H.324 Petri Vuorimaa 14
  14. 14. H.324 • Meant for Plain Old Telephone Systems (POTS) • H.263 can be used for below 64 Kbps video coding + sub-QCIF (128 x 96), QCIF (176 x 144), CIF (352 x 288), 4CIF (702 x 576), and 16CIF (1408 x 1152) • G.723.1 audio codec transmits at 5.3 or 6.3 Kbps Petri Vuorimaa 15
  15. 15. H.324 (cont.) • Can use even 28.8 and 33.3 Kbps modems (V.34) • Codecs are better, but quality is worse than H.320 + H.320 has much more bandwidth than H.324 Petri Vuorimaa 16
  16. 16. H.323 Petri Vuorimaa 17
  17. 17. H.323 • LANs (Internet & Intranet) without QoS support • Clients, multipoint servers, gateways and gatekeepers • Real-time transport protocol (RTP) • New audio codec G.729 (8 Kbps) Petri Vuorimaa 18
  18. 18. Gateway • The gateway allows the integration of H.323 networks with other networks • Tasks: + transformations between media formats + transformations between communication protocols + transformations between audio and video codecs + connection setup and tear-down Petri Vuorimaa 19
  19. 19. Gatekeeper • Gatekeeper takes care of resource reservations • The amount of simultaneous users can be limited • Transforms connection requests from outside to internal addresses and vice versa Petri Vuorimaa 21
  20. 20. Multipoint Server • Required when three or more clients participate the conference • Is composed of two parts: + Multipoint Controller takes care of connections + Multipoint Processor(s) transform(s) media streams • Processors can also combine streams: + Mixing + Switching Petri Vuorimaa 22
  21. 21. Multipoint Server (cont.) • Videoconferences can be set up in three different ways: + unicast, multicast, and broadcast • Three ways of practical implementation: + centralized, distributed, and hybrid • In practice H.323 is implemented on top of IP etc. protocols Petri Vuorimaa 23
  22. 22. Different alternatives Petri Vuorimaa 24
  23. 23. Protocol stack Petri Vuorimaa 25
  24. 24. T.120 • Implements the extra services: + conformance + image transfer + shared workspaces + file transfer + multipoint conferences Petri Vuorimaa 26
  25. 25. T.120 (cont.) • T.120 is composed of three layers: + transport layer + protocol layer + application layer • Transport layer is divided into three levels: + transport protocol + multipoint conference + conference control Petri Vuorimaa 27
  26. 26. Transport layer Petri Vuorimaa 28
  27. 27. T.120 (cont.) • Protocol layer is composed of + image transfer (T.126) + binary file transfer (T.127) + share application transfer (T.Share) + resource reservation (T.RES) • New standard family T.130 is under development Petri Vuorimaa 29
  28. 28. Products • Video conference bridges • Video networks • Video conference rooms • Workstations • Gatekeepers • Gateways Petri Vuorimaa 30
  29. 29. Video conference bridges • Support primarily H.320 and T.120 standard families • Allow multipoint video conferencing • Support few tens of users • Participants either call to the bridge or the bridge setups the connections itself Petri Vuorimaa 31
  30. 30. Video networks • Best possible image quality • Intended primarily for conferences • Uses either ISDN or ATM network Petri Vuorimaa 32
  31. 31. Video conference rooms • Intended for video conferencing • Maintained by companies or operators • Based on H.320 (ISDN) standard family • H.323 (Internet) standard family is coming Petri Vuorimaa 33
  32. 32. Workstations • LAN, ISDN, or modem card • Audio and video cards • Software (e.g., Microsoft Netmeeting, Picturetel, Intel) • H.320 most common, but H.323 is coming (client software is available) Petri Vuorimaa 34
  33. 33. Gatekeepers • Required by H.323 standard family • For example, Intel LANDesk Conferencing Manager + automatic gate keeper + zone management + outbound route management + incoming call routing Petri Vuorimaa 35
  34. 34. Gateways • Intel LiveGateway + bi-directional connection between H.323 and H.320 systems + format transform between H.323 and H.320 systems + supports also H.320 multipoint server + four gates in on PC + either local or gate keeper based administration • Both Intel LANDesk Conferencing and LiveGateway are Windows NT based Petri Vuorimaa 36
  35. 35. Internet telephony • With suitable hardware and software computers connected to Internet can be used for telephony • No extra charges, but the quality is not very good • Gateways to ordinary telephone network also available Petri Vuorimaa 37
  36. 36. Internet telephony (cont.) Petri Vuorimaa 38
  37. 37. Internet telephony (cont.) • Some long distance operators use Internet connections for telephony • Allows the use of compression • For example, 64 Kbps -> 2.4 Kbps Petri Vuorimaa 39
  38. 38. Calls within organization Petri Vuorimaa 40
  39. 39. Public Internet calls Petri Vuorimaa 41
  40. 40. Internet telephony products • Microsoft Netmeeting supports H.323 and T.120 standard families • Includes H.263 video codec • Compatible with Intel and PictureTel products • Utilizes Intel Pentium MMX technology • Other products include White Pine Software CU- SeeMe, IBM Internet Connection Phone, VDOnet VDOPhone Petri Vuorimaa 42
  41. 41. CTI • Computer Telephony Integration (CTI) integrated computers and telephones • Brings savings and increases efficiency (invest return time usually under year) • Several different implementations Petri Vuorimaa 43
  42. 42. CTI block diagram Petri Vuorimaa 44
  43. 43. CTI applications • Voice mail (answering service) • Automatic call transfer • Intelligent call routing and distribution (call centers) • Voice text (timetable, etc.) • Fax requests (information delivered via fax) Petri Vuorimaa 45
  44. 44. CTI applications (cont.) • Interactive telephone services (reservations, orders, etc.) • Call records (automatic recognition of customers) • Gateways (video conference with standard telephone) • Call management (automatic dialing) Petri Vuorimaa 46
  45. 45. CTI implementations • CTI can be based on separate server • Another alternative is to join telephone directly to workstation • Video conference, Internet telephony, and CTI systems can be integrated Petri Vuorimaa 47
  46. 46. Call Center Petri Vuorimaa 48
  47. 47. Integrated system Petri Vuorimaa 49
  48. 48. CTI standards • Multi-Vendor Integration Protocol (MVIP) • System Computing System Architecture (SCSA) • Both are buses connecting different PC cards • Buses are used for call traffic within PC Petri Vuorimaa 50
  49. 49. PC cards Petri Vuorimaa 51
  50. 50. CTI APIs • Microsoft Telephony Application Programming Interface = TAPI (-93) + Windows applications • Novell Telephony Service API = TSAPI (-93) + Novell servers • IBM CTI API + Switches and their interfaces Petri Vuorimaa 52
  51. 51. CTI APIs (cont.) • SCSA framework • Sun Java Telephony API = JTAPI + Java-framework + utilizes above mentioned API definitions Petri Vuorimaa 53

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