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     History of Internet Audio Experiments at McGill (and elsewhere) Jeremy R. Cooperstock Centre for Intelligent Machines Centre for Interdisciplinary Research in Music Media and Technology McGill University. Software available from: http://ultravideo.mcgill.edu Research supported by:.

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slide1
     History of Internet Audio Experiments at McGill (and elsewhere)

Jeremy R. Cooperstock

Centre for Intelligent Machines

Centre for Interdisciplinary Research in Music Media and Technology

McGill University

some early pre history
Some Early (Pre-)History

Eve Schooler: Distributed Music: A Foray into Net Performance (Sept. 1993)

  • synchronized three real-time streams from different hosts; delays in the order of 200 ms
  • difficult for performers to be listeners

Paul Hoffert: CyberSoiree (Feb. 1996)

  • ATM-based technology for audio and video streaming of a four-way jazz performance
  • delay >0.5s delay but musicians earned to compensate through extensive practice

Dimitri Konstantas: Distributed Musical Rehearsal Studio (May 1996)

  • ATM based distributed rehearsal with conductor at different location from musicians
  • 80 ms one-way delay for audio-video synch; echo resulted in "extreme confusion"

Seiji Ozawa: Opening Ceremony Nagano Winter Olympics (1998)

  • conduct choruses on 5 continents: singers in Sydney, New York, Beijing, Berlin, False Bay
  • time lag adjustor used to eliminate satellite delay
system diagram

AC-3 (640 Kbps) (5.1 channels,16 bits @ 48kHz) coded in AES/EBU

SGI Indy

1.5 Mbps

Dolby encoder

SGI Indy

Network

1.5 Mbps

PC Server

Cisco IP/TV

PC Client

System Diagram

McGill UniversityMontreal, Canada

NYU Cantor HallNew York, USA

in action
In action

Sender

Receiver

Receive,check, playback

Transmit

Read

Send Audio

Queue

Receive Audio

Queue

slide7
Recording Studio that Spanned a ContinentMontreal-Los Angeles for the AES 109th Convention, Sept. 23, 2000

12 channels, 96kHz, 24 bits/channel

USC Norris Theatre, LA

McGill Redpath Hall, Montreal

some modern history
Some Modern History

Internet2 Initiative: World's First Remote Barbershop Quartet (Nov. 2000)

  • multi-location quartet; each of the 4 singers in different cities, conductor in 5th
  • network delay variances prevented singers from hearing each other or conductor

Internet2 Initiative: Music Video Recording via Internet2 (Nov. 2000)

  • multi-location music video recording session using real-time streaming video
  • musicians simultaneously connected via timing tracks to a mixing board

Chris Chafe: QoS Enabled Audio Teleportation (Nov. 2000)

  • CD quality sound (750 kbps) of 2 separated musicians in Dallas streamed to Stanford
  • musicians played "together" in same space (Stanford) but delay was severe

John Wawrzynek: Network Musical Performance (May 2001)

  • gestural coding (e.g. MIDI) used to manage data for distributed musical performance
  • musicians at Berkeley and CalTech, playing on MIDI keyboards; local feedback only
playing together experiment new york ottawa remote masters class dec 8 2000
"Playing Together" experimentNew York-Ottawa, Remote Masters class, Dec. 8, 2000

used Litton MPEG-2 codec @ 10 Mbps

Pinchas Zuckerman, Columbia U, NYC

Wu Ji, Canarie ARDNOC, Ottawa

quality vs latency
Quality vs. Latency
  • near-equivalent quality of encoded video at greatly reduced bandwidth
  • but... compression takes time
tolerated synchronicity

musicalactivity

smallensemble

large ensemble

lip synch

compress

acquire

transmit

MPEG*

Tolerated Synchronicity

0

10

20

80ms

30

40

60

70

50

speed of light: Mtl-LA

net latency Mtl-LA

networks

* This figure is a theoretical “best-case” scenario. Actual performance may vary based on local hardware. The manufacturer makes no warranties, either express or implied, and will not be held liable for damage resulting from use of the product. Certain restrictions may apply. Offer void where prohibited by law. Batteries not included.

interactive success
Interactive Success!

Chris Chafe: SoundWIRE (August 2001)

  • streaming pro audio from remote locations for musical collaboration
  • UDP/IP streaming: good results between Armonk, NY and Stanford
  • round trip delay 125ms, musicians able to "catch-up" during pauses
so what does it take
So what does it take?
  • much bigger network pipes ("abusive bandwidth")
    • need Fast Ether (100Mbps) for audio
    • GigE (1000Mbps) for video
    • more efficient network topologies – hops add delay
so what does it take1
So what does it take?
  • much bigger network pipes ("abusive bandwidth")
    • need Fast Ether (100Mbps) for audio
    • GigE (1000Mbps) for video
    • more efficient network topologies – hops add delay
  • more powerful hardware
    • CPU speed (fast process switching, especially for mixed media)
    • pro-audio interfaces with small buffers
so what does it take2
So what does it take?
  • much bigger network pipes ("abusive bandwidth")
    • need Fast Ether (100Mbps) for audio
    • GigE (1000Mbps) for video
    • more efficient network topologies – hops add delay
  • more powerful hardware
    • CPU speed (fast process switching, especially for mixed media)
    • pro-audio interfaces with small buffers
  • more masochistic researchers
sometimes things work1
Sometimes things work...

note: look of extreme anguish

and sometimes they don't

distributed violin duet mcgill universit de montr al for risqnet conference nov 21 2001
Distributed Violin DuetMcGill-Université de Montréal for RISQnet Conference, Nov. 21, 2001
  • connected two Montreal universities via IP over 1 Gbps fiber link
  • uncompressed audio and video
  • < 30ms latency
the medium is the message marshall mcluhan
"The medium is the message" Marshall McLuhan

Cooperstock's Corollary:

"The medium must be faster than the message."

size does matter montreal ottawa nrc distance teaching trial feb 20 2002
Size does matterMontreal-Ottawa (NRC), Distance Teaching Trial, Feb. 20, 2002
  • connected McGill to National Research Council (Ottawa) with SDI video and multichannel 96kHz/24bit audio
  • display on 50" plasma screen (near life-size)
distributed jazz jam montreal stanford ccrma research demo oct 24 2002
Distributed Jazz JamMontreal-Stanford (CCRMA), Research Demo, Oct. 24, 2002
  • uncompressed audio and video @ < 50ms latency
remote video interpretation sign language montreal fredericton unb research trials 2003
Remote Video Interpretation (Sign Language)Montreal-Fredericton (UNB), research trials, 2003
  • DV (patient, physician) exchanged with remote sign-language interpreter

physician's setup

patient's setup

milestones ahead
Milestones Ahead
  • multicast
  • traffic shaping
  • region-of-interest client selection
  • multichannel echo-supression/cancellation
self signal isolation echo suppression
Self-Signal Isolation: Echo-suppression
  • the big problem in videoconferencing
  • same issue for video and vibrosensory data
slide34
achieving high-fidelity distributed interaction, at levels of presence and latency that support the most demanding applications and doing so in spite of sensor and bandwidth limitations