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20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
20021028-Videoconferencing-Chen.ppt
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20021028-Videoconferencing-Chen.ppt

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  • 1. Challenging 5 Common Assumptions about Videoconferencing Milton Chen Computer Systems Lab Stanford University Presented at Internet2 Advanced Applications Track 10/28/2002
  • 2. The Stanford Video Auditorium desktop interface 15’ x 5’ video wall
  • 3. Video Auditorium publicity/users <ul><li>Intel president Paul Otellini’s Intel Developer Forum keynote </li></ul><ul><li>Invited demo to NASA headquarters for Paul G. Pastorek </li></ul><ul><li>CANARIE, Canada </li></ul><ul><li>CUDI, Mexico </li></ul><ul><li>Comdex, Brazil </li></ul><ul><li>IBM Almaden Lab </li></ul><ul><li>Manhattan College </li></ul><ul><li>Hopkins Marine Station </li></ul><ul><li>Stanford Medical School </li></ul><ul><li>Stanford Learning Lab </li></ul><ul><li>Stanford Center for Design Research </li></ul><ul><li>Berkeley Bioengineering Lab </li></ul><ul><li>Universidade Federal do Rio Grande do Sul, Brazil </li></ul>
  • 4. Outline <ul><li>Common assumptions </li></ul><ul><ul><li>Technology </li></ul></ul><ul><li>1. High-fidelity AV requires dedicated hardware </li></ul><ul><li>2. Difficult to install and use </li></ul><ul><ul><li>Human factors </li></ul></ul><ul><li>3. Life size displays are ideal </li></ul><ul><li>4. Floor control requires interactive frame rate </li></ul><ul><li>5. Eye contact is difficult </li></ul><ul><li>Beyond MCU and H323 </li></ul><ul><ul><li>Peer-to-peer </li></ul></ul><ul><ul><li>Stanford’s Port Bootstrap Protocol </li></ul></ul><ul><ul><li>Personal directory </li></ul></ul><ul><li>An evaluation of distance learning at Stanford </li></ul><ul><li>Why videoconferencing is not ubiquitous </li></ul>
  • 5. 1. High-fidelity low-latency AV requires dedicated hardware
  • 6. Your PC outperforms all dedicated systems $700 Pentium 4 computer $7000 systems outperforms                                                
  • 7. Comparison of videoconferencing solutions * CUSeeME, iVisit, Yahoo messenger have unacceptable latency 400 Kbps 720x480 many AccessGrid, VRVS 3000 Kbps 720x480 1 WIDE DVTS 200 Kbps 352x288 4 Polycom, Sony, … 16 to more than 100 1 1 Max number of links 2000 Kbps 720x480 Vbrick 100 Kbps 720x480 Stanford Video Auditorium 200 Kbps 352x288 NetMeeting BW required at 352x288 15fps Max video resolution
  • 8. demo
  • 9. A scalable AV streaming architecture * TrueSpeech 8.5 * MPEG-4 * Encrypted, AES (Rijndael), streaming * Simultaneous AV recording * Perceptual streaming adapts to network conditions audio capture audio compress audio send audio receive audio decompress audio render video capture video compress video send video receive video decompress video render
  • 10. Beyond MCU and H323 <ul><li>MCU vs. peer-to-peer </li></ul><ul><ul><li>Scalability </li></ul></ul><ul><ul><li>Ease of deployment </li></ul></ul><ul><li>H323 vs. Stanford’s Port-Bootstrap Protocol </li></ul><ul><ul><li>Firewall </li></ul></ul><ul><ul><li>Ease of deployment </li></ul></ul><ul><li>Personal directory </li></ul>
  • 11. 2. Videoconferencing systems are difficult to install and use
  • 12. One click operation <ul><li>To use the Video Auditorium </li></ul><ul><ul><li>“ Nothing” to install </li></ul></ul><ul><ul><li>One click on the html speed dial </li></ul></ul><ul><ul><ul><li><OBJECT </li></ul></ul></ul><ul><ul><ul><li>CLASSID=&quot;CLSID:E80F7B8F-7906-4A89-B59E-B19871F474A9&quot; </li></ul></ul></ul><ul><ul><ul><li>CODEBASE=&quot;runtime/VA_Start.ocx#Version=-1,-1,-1,-1&quot;> </li></ul></ul></ul><ul><ul><ul><li><PARAM NAME=&quot;addr&quot; VALUE=&quot;stanford -client_only&quot;> </li></ul></ul></ul><ul><ul><ul><li></OBJECT> </li></ul></ul></ul>Makes conferencing as simple as surfing the web
  • 13. 3. Life size displays are ideal
  • 14. Each video should be between 6 ° and 14° wide <ul><ul><li>* 12 people sat 10’ from the display Subjectively, people reported 6 ° as minimum and 14° as ideal. Life size is 12 °. </li></ul></ul>
  • 15. Balance between size and head movements * 12 people viewed 9 and 36 students on a large and immersive display. Immersive display requires head movements to see all the students. 9 ° 14 ° 7 ° 4 °
  • 16. 4. Effective floor control requires interactive frame rate
  • 17. Minimum required frame rate <ul><li>Interactive 10 fps </li></ul><ul><li>Tolerable 5 fps </li></ul><ul><ul><li>[Tang and Isaac ’93] </li></ul></ul><ul><li>Lip synchronization 5 fps </li></ul><ul><ul><li>[Watson and Sasse ’96] </li></ul></ul><ul><li>Content understanding 5 fps </li></ul><ul><ul><li>[Ghinea and Thomas ’98] </li></ul></ul><ul><li>Sign language recognition 1 fps </li></ul><ul><ul><li>[Johnson and Caird ’96] </li></ul></ul>
  • 18. Gesture Detection Algorithm input image frame difference after erosion Visualization of algorithm
  • 19. Requires 10% of full motion bandwidth full-motion (10 fps) gesture-sensitive (0.2 fps) * MPEG4 encoded at 320x240
  • 20. Gesture sensitive allows dynamic discussion 15 fps ~0.2 fps 0.2 fps * 8 groups of 4 people during a discussion
  • 21. 5. Eye contact is difficult
  • 22. Eye contact fires up our brain [Kampe et al. ’01]
  • 23. Eye contact is difficult Looking into the camera Attempting eye contact
  • 24. Solutions to eye contact Half-silvered mirror [Rosenthal ’47] MAJIC [Okada, et al. ’94] ClearBoard [Ishii, et al. ’92] GazeMaster [Gemmell, et al. ’00]
  • 25. A simple solution Hydra [Sellen, Buxton, and Arnott ’92]
  • 26. Eye contact sensitivity is high <ul><li>Spatial perception task </li></ul><ul><li>As good as Snellen acuity </li></ul>[Gibson and Pick ’63] 2 m * 6 observers judged 1 looker looker observer 0 8.5 -8.5 0 100 stdev = 2.8 ° Eye contact (%) Angle (deg)
  • 27. Sensitivity is symmetric <ul><li>Cline ’67 </li></ul><ul><li>Kruger and Huckstedt ‘69 </li></ul><ul><li>Anstis, et al. ’69 </li></ul><ul><li>Stokes ’69 </li></ul><ul><li>Ellgring ’70 </li></ul>PicturePhone camera above display Hydra camera below display
  • 28. Methodology <ul><li>* Two rooms can be linked in a videoconferencing session </li></ul>Observers watch videos of looker and judge eye contact large display with camera at the center Record lookers gazing at different targets
  • 29. Sensitivity is asymmetric * 16 observers judged recorded videos of 1 looker
  • 30. An anatomical explanation looking at you looking sideways looking up looking down eye closing Illustrations from The Artist’s Guide to Facial Expression [Faigin ’90]
  • 31. Sensitivity is less in conversation * 16 observers judged videos of 1 looker (down) recorded conversation
  • 32. Sensitivity is less in video * 16 observers judged 1 looker in conversation (down) face-to-face video
  • 33. We are biased to perceive contact angle eye contact (%) sideway, up down down & video down & video & conversation Snellen Acuity Conferencing Acuity 0 100
  • 34. Maximum camera to eyes distance * Assuming a sensitivity of 7 ° 12” 8’ Wall size 3” 2’ Desktop 1.5” 1’ Palm held camera to rendered eyes distance minimum viewing distance device
  • 35. Eye contact in the Video Auditorium
  • 36. Why is videoconferencing essential to distance learning: An evaluation of distance learning at Stanford
  • 37. Distance learning at Stanford <ul><li>Remote students can call in during class </li></ul><ul><li>Instructor cannot see the remote students </li></ul>a 1969 classroom a 2002 operator console a 2002 lecture viewer
  • 38. Students like distance learning * 120 students, 15 TAs, and 41 faculty
  • 39. Learning is less effective * 120 students, 15 TAs, and 41 faculty
  • 40. F2F interaction is important F2F is important for lecturing and crucial for discussions
  • 41. No interaction with remote students <ul><li>Classroom observation of 4 CS classes </li></ul><ul><ul><li>Instructor on average asked 9 questions per session </li></ul></ul><ul><ul><li>Local students on average asked/made 3 questions/comments per session </li></ul></ul><ul><ul><li>Remote students spoke once in 6 month </li></ul></ul>
  • 42. Value of video beyond audio <ul><li>Cues only transmitted by the visual channel </li></ul><ul><ul><li>Negative feedbacks, … </li></ul></ul><ul><li>Emotional bond </li></ul><ul><ul><li>Establishing and maintaining relationships </li></ul></ul><ul><li>Can you imagine it? </li></ul><ul><ul><li>A new face, … </li></ul></ul>
  • 43. A proposal
  • 44. The world’s largest video wall: link all Internet2 members for Spring 03 <ul><li>Developed technology </li></ul><ul><li>One Mouse </li></ul><ul><li>AV stream migration </li></ul><ul><li>Bandwidth: 2 x 300 x (100 Kbps + 10 Kbps)  60Mbps </li></ul><ul><li>Cost: 10 P4 laptops + 10 portable projectors  $30K </li></ul>
  • 45. A prediction
  • 46. Why all videoconferencing products has failed A plane that does not fly is not a plane First flight, Wrights 1903 <ul><li>A videophone that limits communication is not a videophone </li></ul><ul><ul><li>poor audio fidelity </li></ul></ul><ul><ul><li>poor video fidelity </li></ul></ul><ul><ul><li>excessive latency </li></ul></ul><ul><ul><li>no eye contact </li></ul></ul><ul><ul><li>poor lip synchronization </li></ul></ul>
  • 47. Threshold of quality for the 2nd revolution first mobile phone, 1924 first handheld phone, 1973 1 st Revolution: Possible 2 nd Revolution: Practical first videoconferencing system, 1927
  • 48. Conclusion <ul><li>Common assumptions </li></ul><ul><li>1. High-fidelity AV requires dedicated hardware higher on a PC </li></ul><ul><li>2. Difficult to install/use one click </li></ul><ul><li>3. Life size displays are ideal 6 ° to 14 ° </li></ul><ul><li>4. Floor control requires at least 10fps 0.2 fps avg </li></ul><ul><li>5. Eye contact is difficult 7 ° down </li></ul><ul><li>Videoconferencing is essential to distance learning </li></ul><ul><li>A MCU-less and H323-less future </li></ul>
  • 49. You already have a one-click high-fidelity multiparty videoconferencing system We are at the dawn of a videoconferencing revolution that will fuel the demand for a 1000X increase in available bandwidth
  • 50. <ul><li>Acknowledgement </li></ul><ul><ul><li>NASA </li></ul></ul><ul><ul><li>Intel </li></ul></ul><ul><ul><li>Sony </li></ul></ul><ul><ul><li>Interval Research </li></ul></ul><ul><ul><li>Wallenberg Global Learning Network </li></ul></ul><ul><ul><li>Department of Defense </li></ul></ul><ul><li>Future work </li></ul><ul><ul><li>Gold release for Feb 2003 </li></ul></ul><ul><ul><li>SDK </li></ul></ul><ul><ul><li>The Wall  </li></ul></ul>

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