1. Project Presentation

2. Reminder 13th November 1 – 5pm Read your emails/Visit web sites for more information (later)

3. Reminder Please check your project title Please check your grades

4. Reviews Categories 4 categories No submission Did not demonstrate understanding Understand and summarize Understand, think and summarize

5. What I Hope You Have Learned How to read papers? How to evaluate papers? Think critically about what you read

6. Recent Papers from conferences

7. Sessions Session 1: Movies and Music Session 2: Peer-to-Peer Streaming Session 3: Power-Friendly

8. Movies and Music Session 1

9. Characterizing DVD Wu-Chi Feng et. al. Packet Video 2003

10. Motivations Lots of DVD videos available How are they encoded? What is the implications to our research?

11. DVD data 107 video streams 140 hours 80 DVDs

12. Bit-rates Maximum DVD bit rates 10 Mbps Found on DVD 3.3 – 7.8 Mbps VBR Quantization values change over time (only Spy Kids is CBR)

13. GOPs and Sequences Each GOP was encoded into a different sequence GOP sizes: around 12 frames

14. NUS.SOC.CS5248 OOI Wei Tsang Sequence sequence header: width height frame rate bit rate :

15. NUS.SOC.CS5248 OOI Wei Tsang GOP: Group of Picture gop header: time :

16. NUS.SOC.CS5248 OOI Wei Tsang Picture pic header: number type (I,P,B) :

17. Frame Patterns Most videos have varying Number of frames within a GOP Frame patterns (ID4 has 134 unique GOP patterns)

18. Frame Pattern Scene Change Detection used extensively IPPPPPPP quite common!

19. Implication to Research Cannot assume fixed frame pattern Cannot always drop B frames

20. Network Musical Performances UC Berkeley NOSSDAV 2001

21. Goal Show that networked musical performances (NMP) can be done

22. Observation Stanford – Berkeley (40 miles) RTT ~4 ms 0.72 meters Berkeley – Caltech (375 miles) RTT ~28 ms 4.88 meters

23. Observation Musical instruments have long production latency

24. Observation Don’t send audio, send command Keeps “states” of the current music performance

25. Example NoteOn(channel, note, velocity) NoteOff(channel, note)

26. Packet Loss Recovery Lost/Late NoteOn skipped Lost/Late NoteOff executed

27. Packet Loss Recovery Guard packets Recovery journals

28. Bandwidth 20 MIDI command per seconds 640 bps With recovery journals ~7 kbps

29. Experience Lost/Late NoteOn/NoteOff But musician can adjust and play fluidly

30. Peer-to-Peer Session 2

31. P2Cast Yang Guo et. al. WWW 2003

32. NUS.SOC.CS5248 OOI WEI TSANG Patching Time Client Request mcast unicast

33. NUS.SOC.CS5248 OOI WEI TSANG Patching Time Client Request Patching Window: W mcast

34. Problem with VOD IP Multicast usually assumed Patching still requires unicast connections

35. P2Cast

36. New Session

37. Existing Session + Patch ? ? Fat Pipe First

38. Patch Server Selection

39. Patching Stream patching stream base stream

40. Tree Example

41. Failure Recovery X

42. What if Patch server failed? Base server failed?

43. PROMISE Mohamed Hafeeda et. al. ACM MM 2003

44. Problem P2P with streaming One peer may not have enough bandwidth Need to aggregate multiple peers

45. Architecture B/2 B/4 CollectCast

46. Select sending peers Monitor network Assign streaming rates and data segments Decide when to change peers

47. PROMISE Operations I want to watch LOTR:T2T

48. PROMISE Operations These are the candidate s..

49. PROMISE Operations Max expected goodness Subject to rate constraints

50. PROMISE Operations Here are your peers!

51. PROMISE Operations Send these..

52. PROMISE Operations Should I switch?

53. PALS Reza Rejaie et. al. NOSSDAV 2003

54. Problem P2P with streaming One peer may not have enough bandwidth Need to aggregate multiple peers Using layered coding With congestion control

55. Sliding Window playout time window

56. Packet Assignment playout time S1S2

57. Sending Mechanism Request packets in priority order Sender must send in order Next request overwrites previous one

58. Power-Friendly Session 3

59. GRACE-OS Wanghong Yuan SOSP 2003

60. Motivation Mobile devices run on battery How to save battery?

61. Dynamic Voltage Scaling Example: AMD Athlon 4 PowerOn {300, 500, 600, 700, 800, 1000}MHz Energy  V 2

62. CPU Scheduler When to execute a task How long to execute it How fast to execute it

63. NUS.SOC.CS5248 OOI WEI TSANG CPU Reservation “I need C units of time, out of every T units.”

64. Probability Distribution cycles Cum. Prob.

65. CPU Requirements “I need C units of time, out of every T units.”

66. Speed Schedule speed time

67. Finding Speed Schedule Let task execute at speed v x during cycle x execution time: power: average power:

68. Optimize This Minimize: Subjected to:

69. Implementation Linux Kernel AMD Athlon 4 716 lines of code

70. Findings Probability distribution is quite stable Able to meet deadlines with bounded miss ratio Save energy by 7 – 72%

71. Proxy Assisted Streaming Prashant Shenoy et. al. MMCN 2003

72. Motivation Power-aware streaming to mobile device save energy in decoding frames save energy in receiving packets

73. Architecture server/proxyclient Here’s my energy budget for decoding + network reception and max resolution

74. Architecture server/proxyclient OK, what should I send?

75. Information Needed Map stream properties to energy requirement Need to know decoding time of a frame

76. Frame Decoding Time

77. Estimating Frame Decoding Time

78. Transcoding If current stream would exceed client decoding energy budget Need to transcode by reducing quality

79. Transcode to what? E = estimated energy needed while E > energy budget reduce quality by ε E = estimate energy needed

80. Transcoded Streams server/proxyclient

81. Reducing NIC Energy NIC has two modes : active/sleep Client can activate NIC only when packets are expected.

82. Burst Transmission I will start transmitting at 10:12:54.86 pm

83. Evaluations Decoding Time Frame Number

84. Evaluations NIC Idle Uptime: 2 – 20%