Audio Networking

1
Audio Networking

• Bob Moses
• AES Vice President
• Western Region USA/Canada

Updated May 21, 2002
2
Presentation Outline

• Why Network Audio?
• How?
• Ramifications
• Listening Tests

3
Why Network Audio?

• Put an engineer, marketing exec., business
  development mgr, and consumer in a room and ask
  them why network your audio system?
• Engineer Because we can
• Marketing To exploit new opportunities
• BizDev To make lots of money
• Consumer To access every recording ever made,
  instantly

4
Engineering Perspective

• Digital Audio systems benefit by being networked
• Share resources
• Lowers cost
• Increases performance
• Provide a modular upgrade path
• Partition the system so that only those things
  that need to change must change
• Enhanced user interface
• Graphical
• Single and multiple points of control

5
Engineering Anatomy of a modern audio widget
6
Evolution the PC meets Darwin

• Jim Reekes, Founder of Kebango
• A general-purpose computer is an instrument of
  torture. They do many things, but nothing very
  well. They paradoxically implement a continually
  changing set of standards. Of the top 10 selling
  software packages, 6 cure problems created by
  other programs.

7
Introducing the Home Network

• Carries all types of data
• Files (TCP/UDP, SCSI, etc.)
• Audio streams (MP3, Real, WMA, Dolby/DTS,
  Redbook, 24/96, multichan, etc.)
• Video streams (Real, MPEG4, uncompressed SD HD,
  MPEG PS or TS, DV, etc.)
• Control monitoring protocols (RC5, AVC, ASCII,
  JAVA/Jini, UPnP, proprietary, etc.)
• Transparent to the data
• Quality of service for streaming A/V exceeds
  human perception (bounded latency, low jitter, no
  drop outs)
• Guaranteed delivery with handshaking, retries,
  time outs, etc.
• Consumer friendly
• Low cost
• Easy to set up and use
• Robust
• Secure, but not finicky

8
Many Contenders for the Home Network

• IEEE 1394
• Ethernet
• IEEE 802.11a
• HomeRF
• HomePNA
• HomePlug
• Etc.
• More details later.

9
Example Home Network
10
Marketing New products!

• Information Appliances Personal computers
• Home Internet terminals
• Personal digital assistants
• Digital mobile telephones
• Boom boxes
• Digital Jukeboxes
• Internet Radios
• Set top boxes
• Wrist watches
• Etc., etc.

11
Business Development More money!

• 41 of US households are now online (US Dept
  Commerce, 2002)
• 71 of U.S. households will be online by 2003
  (Forrester)
• 18,000,000 people have broadband at home now
  grew 121 in 2000-2001 (Arbitron/Edison Media)
• 34 of U.S. population regularly streams music
  today (Arbitron/Edison Media)
• 40 of U.S. population will be listening to
  Internet radio by 2003 (Webnoize)
• Digital downloads will grow from 3 of online
  music sales in 2001 to 30 in 2006 (Jupiter Media
  Metrix)
• The market for smart handheld devices will grow
  from 12.9 million units in 2000 to over 63.4
  million by 2004 (IDC)
• The worldwide market for information appliances
  will exceed 89 million units, or 17.8 billion,
  in 2004, up from a market of 11 million units and
  2.4 billion in 1999 (IDC)
• Napster enlisted more users in 1 year than AOL
  did in 15 years.

12
Broadband The Next Big Thing

• Broadband Internet access is booming
• 51 of the 2.3 billion hours spent online in the
  month of January 2002 were via broadband,
  outpacing dial-up Internet access for the first
  time.
• Forrester Research predicts that 38 million
  European homes will have broadband Internet
  access by 2006.
• An estimated 13.4 million homes in North America
  have high-speed connections now, and the US
  Government is being heavily lobbied to raise that
  to 80 by the end of 2003.
• Many devices want access to Broadband services,
  necessitating a home network
• Multiple PCs for various members of the family
• Streaming and downloadable media (MP3, Real
  Video, etc.)
• Music metadata look up services (e.g. CDDB)
• Gaming
• Intelligent appliances

13
Home Networking is on the Rise

• 12 million homes expected to have home networks
  by 2004 (Parks Associates)
• Most popular reasons for a home network (HomeRF)
• Sharing high speed internet 39.1
• Sharing dial up internet account 37.2
• Sharing printers 34.7
• Sharing audio 33.3
• Sharing files 31.8
• Sharing drives 26.4

14
Where did this come form?

• The Internet found a killer app digital music
• immediate gratification!
• transcends all cultures, ages, and personal
  preferences
• portable, cheap, low power, tremendous access
• Convenience vs quality
• Leverage advances in
• Larger/cheaper memory
• faster CPU speed
• broadband Internet access
• portability
• Convergence
• Computer industry trying to entice consumers
• Consumer industry trying to sell new products
• Music enthusiasts trying to access vast amounts
  of music
• Musicians trying to reach listeners (95 of the
  music is owned by five large companies. Only
  5-10 of the money you pay for a CD goes to the
  artists. )

15
New Business Models

• The CEO of the Consumer Electronics Association
  recently stated, The content industry wants to
  turn the Play button into a Pay button
• Subscription services (AOL, MSN, Napster, etc.)
• Music lockers (my.mp3.com)
• Peer to peer networking
• Napster
• Fastrack / MusicCity/Grokster (1.5 billion
  illegal downloads in Sept 2001!)
• Gnutella
• Audio Galaxy
• Hardware is a loss leader
• What does that mean for audio quality?
• Brick and Mortar stores are they going away?

16
Online Music Services

• Real Networks
• MSN Music
• mp3.com
• Live365
• Shoutcast
• Icecast
• Loudeye Radio
• Yahoo Music
• Napster
• etc.

17
How do we network Audio?

• Two methods Streaming and File Delivery
• Streaming synchronous, uninterruptible flow of
  audio
• File Delivery asynchronous, interruptible
• Streaming is higher quality, but places higher
  demands on the network
• File transfer is easy and cheap, but requires
  compression of the audio data for practical
  systems (today)

18
Networks that Stream

• IEEE 1394
• Simple, cheap, consumer-oriented
• Short distances (lt1km)
• Super high performance
• Cobranet (Ethernet)
• Proprietary
• Expensive
• Pro audio applications only
• ATM
• Expensive
• Lack of standards for applications
• Optimized for wide area

19
Networks that transfer files

• Ethernet
• IEEE 802.11
• HomePlug
• HomePNA
• IEEE 1394

20
Home Networking Technologies Ethernet

• Supports
• Ubiquitous - 300 million Ethernet nodes
  worldwide!
• Supports speeds up to 10 Gbps
• CSMA/CD protocol allows asynchronous transport,
  breaks down during heavy networking loading
• Like 1394, Ethernet supports
• Most physical media copper, fiber, wireless
• A peer to peer architecture that allows any node
  to communicate with any other node, without PC
  intervention
• Low cost chipsets from many silicon vendors

21
Home Networking Technologies Ethernet
22
Home Networking Technologies IEEE 802.11

• Wireless Ethernet
• Collision sensing multiple access / carrier
  avoidance protocol
• Wired Equivalent Privacy (WEP) security via
  authentication and encryption. There have been
  recent reports that this security has been
  compromised by hackers.
• Several Flavors

23
Home Networking Technologies HomeRF

• Competes with IEEE 802.11 for wireless Ethernet
  applications
• Uses Shared Wireless Access Protocol (SWAP)
• Operates in 2.4 GHz band, up to 100 meters, up to
  10 Mbps. 
• Supports up to 8 simultaneous voice connections
  with 10 ms bounded latency.
• 128-bit encryption with tamper-resistant 32-bit
  initialization vector

24
Home Networking Technologies IEEE 1394

• Nearly ideal for home networking
• Up to 400Mbps (1394a), or 3.2Gbps (1394b)
• Up to 63 nodes per bus, and up to 1023 buses
  connected via bridges (per 1394.1 standard)
• Isochronous transport handles up to 64 isoch
  streams per bus
• Asynchronous transport addresses up to 256
  terabytes on every node
• Supports most physical media copper, fiber,
  wireless
• Peer to peer architecture allows any node to
  communicate with any other node, without PC
  intervention
• Supports international standard protocols for all
  relevant audio / video formats, TCP/IP, storage
  devices, device control, and so on.
• Adopted by hundreds of companies and most
  industry consortiums for next-generation digital
  appliances
• Low cost chipsets available from many silicon
  vendors

25
Home Networking Technologies IEEE 1394

• Physical Constraints

Against the rules, but it works
26
Home Networking Technologies Wireless IEEE 1394

• IEEE 802.11a carries 1394 isoch and async traffic
• Or, HiperLAN2 can be used too
• 54Mbps, good enough for 1 or 2 MPEG streams and
  lots of audio channels
• Currently under development, demos have been made
  for several years at various trade shows

27
Home Networking Technologies HomePNA

• Home Phoneline Networking Alliance (HomePNA)
• 4MHz 10MHz band (well above POTS)
• 25 devices, up to 500 feet apart, in buildings up
  to 10,000 square feet
• HPNA 1.0 Data rate up to 1 Mbps
• HPNA 2.0 Data rate up to 10 Mbps
• Interoperable with Ethernet and IEEE 802.11 /
  HomeRF

28
Home Networking Technologies HomePlug

• Home Plug Alliance selected Intellon technology
  for HomePlug specification
• Operates over regular 2 phase power circuits
• OFDM in the 4.3MHz 20.9MHz band.
• Data rate up to 10 Mbps
• MAC protocol is a variant of the well-known
  CSMA/CA protocol.
• Up to 256 devices can be connected in homes up to
  5,000 SQFT
• Security is provided by encryption and signal
  attenuation. However, powerline technologies are
  often accessible to neighbors sharing the same
  transformer.

29
Which Network(s) Should I Use?

• Data Ethernet, 1394, 802.11, HomePNA, HomePlug
• Audio
• Compressed Ethernet, 1394, 802.11, HomePNA,
  HomePlug
• Streaming 1394
• Video
• Compressed Ethernet, 1394, 802.11, HomePNA,
  HomePlug
• Streaming 1394

30
Heterogeneous Networks

• No network is perfect, and no single network will
  win universal adoption
• Heterogeneous networks are comprised of two or
  more network technologies
• Bridges and gateways are crucial devices for
  connecting subnets
• Bridges connect two or more networks running the
  same protocol stack (e.g. HomePNA to Ethernet)
• Gateways connect networks that use different
  protocols (e.g. Ethernet to 1394)
• Heterogeneous networks allow us to add
  functionality to the home network incrementally
• e.g. begin with an Ethernet PC LAN
• Add 802.11 or HomePNA to reach remote zones
• Add 1394 to distribute A/V
• Replace original Ethernet with 1394b to increase
  speed and QoS

31
Ramifications

• Systems evolve from autonomous devices to
  communities of devices.
• Control becomes decentralized and migrates to the
  edge devices.
• This is a revolutionary change (not evolutionary)

32
Paradigm Shifts

• Once there is too much information to own, we
  must evolve methods to access and organize it.
• Todays systems are equipment-centric, and very
  complex.
• Tomorrows systems need to be content-centric,
  and very simple.
• The distinction between ownership, and renting,
  and a service is already blurred in the video
  industry. Thats likely to happen in the music
  industry as well.
• Duplicating and distributing plastic disks is
  barbaric.

33
The user interface gets really cool!
34
Content-Based Searching

• Chris Weare Ted Tanner
• Breakthroughs in machine learning, pattern
  recognition, and feature extraction can be
  applied to audio to characterize the similarity
  between two recordings.
• A neural network was trained with data from over
  115,000 songs to produce a commercial system that
  provides over 90 success.
• Humans no longer need to listen to music because
  computers can be trained to listen for them!

35
Content Protection

• Copy inhibit bits (SCMS)
• Watermarking
• Fingerprinting
• SDMI
• DTCP
• Do any of these technologies truly work?
• Should we create technical solutions to legal
  problems, or legal solutions to technical
  problems?

36
Metadata

• Elizabeth Cohen
• We generate terabytes of new music data each day
  
• The machine and format I record on today wont be
  around in 20 years.
• Its important to preserve the music experience
  itself, not just the bitstream
• How do you record and regenerate an experience?
  
• Some of our audio treasures might be lost when
  future devices are unable to play them back.
• Elizabeth Cohen recommends that if a device
  leaves a footprint on the audio, the content must
  describe it via metadata.

37
Dont forget about the Creative Team During
Encoding!

• Bob Clearmountain
• Producing content for the Internet is not merely
  a file transfer process creative decisions must
  be made in the mastering process that ultimately
  affect the listening experience.
• The process of compressing audio for the low
  bandwidth of the Internet is very similar to the
  old days of squeezing music into a plastic groove
  of a vinyl LP during mastering, and that the
  compromises involved should be a creative process
  involving the creative team.
• Internet mix should also be considered in
  addition to the CD, radio, extended dance mix,
  and other mixes.

38
Most important ramification Audio Quality

• Better or worse?
• Streaming networks promise to carry data between
  devices in their original format without A/D and
  D/A conversion.
• File delivery systems must compress the data.
  This is a violent process that significantly
  changes what we hear!

39
Compression Formats

• Required for asynchronous networks
• MPEG-1 Layer 3 (MP3)
• MPEG 2, 4, MPEG 7
• AAC
• Windows Media
• Real Audio/Video
• Quicktime
• Ogg Vorbis
• VQF
• Beatnik
• etc.

40
Listening Tests

• Edward II Wicked Men
• Track 7 Shes Gone to California
• Original (44.1kHz, 16-bit)
• Compressed Formats
• MP3
• WMA 7.0
• Real Audio 6.0
• (AAC can not be played back due to copy
  protection glitch)
• 160Kbps
• Random ordering
• 64Kbps
• Random ordering