Practical Applications for Digital Audio Networking

Practical Applications for
Digital Audio Networking II

Umberto Zanghieri - ZP Engineering srl
(The Smart Guy who is not here today and would be happy to talk
about this topic for two days)

Bob Vanden Burgt - Link USA/Link Italy
(The Not So Smart Guy doing the Presentation who promises to be
done in
one hour)
People and Products connecting the world of entertainment

Digital Audio Networking
History of Digital Audio Networking
AES & Evolution of OSI Layers
The Current State of the Industry
(fragmented at best)
Transport Protocol Wars
Remote Control & Monitoring
Connectivity Challenges &
Practical Examples
Where are We Going from Here?


Analog Distribution


Digital Distribution


Analog v. Digital Cabling
48-channel balanced analog multicore
Weight  approx. 1,3 kg/m; 97 kg for 100m + 25kg cable drum
Cost  approx. 20 times the cost of a CAT5e ruggedized cable
Outer diameter  28 mm

vs

2 x CAT6 + 2 x AES (Eurocable)
Weight  approx. 0,38 kg/m
Outer diameter  18 mm


Moving Audio Around Digitally in
a Live Production Environment

What do we need to care about?
Quality (Fidelity)
Speed & Priority (Latency -
milliseconds/microseconds, QoS)
Synchronization (Clocking)
Distance (Coax, CAT6, MMF, SMF)
Flexibility / Compatibility
(Topologies / Sharing Hardware)
Cost
Reliability / Redundancy
Compatibility / Standards AES,
IEEE


History of Digital
Networking
Pulse Code Modulation (PCM) &
Sampling
In 1924 while working for AT&T
Harry Nyquist studied this
sampling technique and
developed the Nyquist Sampling
Theorem. This theorem states
that an analog signal can be
uniquely reconstructed, without
error, from samples taken at
Sampling Rate = 2(BW) = 2(3300 equal time intervals if the
Hz) = 6600 Samples per Second sampling rate is equal to, or
greater than, twice the highest
frequency component in the
analog signal.

Pro Audio & PCM
Linear PCM (uncompressed), typ. Wordlength (bit depth) from 16 to 24 bits with sampling
frequencies between 44-192kHz

Pulse-code modulation (PCM) is a method used to digitally represent sampled analog
signals. It is the standard form for digital audio in computers and various Blu-ray, DVD and
Compact Disc formats, as well as other uses such as digital telephone systems. A PCM
stream is a digital representation of an analog signal , in which the magnitude of the analog
signal is sampled regularly at uniform intervals, with each sample being quantized to the
nearest value within a range of digital steps.

PCM streams have two basic properties that determine their fidelity to the original analog
signal: the sampling rate, which is the number of times per second that samples are
taken; and the bit depth, which determines the number of possible digital values that each
sample can take.


History of Digital
Networking
Public Switched Telephone Network
(PSTN)
Coder-Decoder (CODEC) or ADC / DAC


History of Digital
Networking
Pulse Code Modulation
Public Switched Telephone Network
(PSTN)
CODECs use a method
called Pulse Code
Modulation (PCM) to
convert the analog signals
to digital bit streams. PCM
uses a technique called
sampling to obtain
instantaneous voltage
values at specific times in
the analog signal cycle.
This sample generates a
Pulse Amplitude
Modulated (PAM) signal.

Audio-over-Ethernet
Linear PCM (Reference – CD is 16 bit resolution, 44.1kHz)


History of Digital
Networking

Recording in the 1990’s
•Digital Audio Workstations

•Token Ring Networks for
moving audio data (not real time)

•Evolution of the DSP > Why
shouldn’t the transport be
digital?


History of Digital
Networking
AES Standards
• 1985 AES3 – AES/EBU
(RS422 Derived)
2 Channels @ 192kHz

• 1991 AES10 – MADI
(FDDI – Fibre Disrtib Data Interface)
56 > 64 Channels @ 96kHz

• 2005
AES50>SuperMAC/
HyperMAC (Midas-KT)
24 Ch @ 96kHz/192 Ch @ 96kHz

Audio-over-Ethernet
What is it?
Deployment of an Ethernet network to transfer digital audio streams in real-time

Linear PCM (uncompressed), typ. Wordlength (bit depth) from 16 to 24 bits with
sampling frequencies between 44-192kHz

•multichannel, high channel count (~60 channels in each direction)

•audo channels are generally bundled in clusters

•low latency (< 6 ms) but with DSP transport expectations = <1ms

•no packet loss in normal operating conditions


Audio-over-Ethernet
(AoE) – why?
Larger maximum distance
(60-70 m with analog cables, ~ 100 m AoE on copper , ~2km AoE on fibre)

rerouting and splitting are now possible - Splits are Free!
(without manual changes to connections, without manual patch bays)

redundancy at reasonable costs

control data and audio transport can be combined on a single connection

cables are less expensvie and less bulky
64-channel balanced analog multicore (data from Eurocable)
Weight  around 1,3 kg/m
Cost  around20 times the cost of a ruggedized CAT5e cable


Audio-over-Ethernet
Ethernet transport (IEEE 802.3)
1980  Ethernet
1985  IEEE 802.3

1990  10 Mbps (10baseT) Used for first AoE implementations CobraNet

Enough bandwidth for reasonable multichannel
1995  100 Mbps (100baseTX) operation

1999  1000 Mbps (1000baseT) Hundreds of channels can be allocated

2002-2008  10 Gbps (10GbaseT)

2007-2011  40/100 Gbps

2010 - 12  Ethernet AVB


Ethernet (IEEE
802.3)
100
40

Bitrate
in Gigabits

10

IEEE 0.1 1
802.3 0.01

19 19 19 19 19 19 20 20
73 80 83 90 95 99 06 10


Ethernet (IEEE
802.3)
100
40

Bitrate
in Gigabits

ARPANET:
first msg sent
10
Ethernet TCP specs
(Metcalfe (Vint Cerf
& Boggs) & Bob Khan)

IEEE 0.1 1
802.3 0.01

19 19 19 19 19 19 20 20
73 80 83 90 95 99 06 10


ISO/OSI protocol layers

HOST LAYERS 7 APPLICATION Network to application

6 PRESENTATION Data representation
And encryption

5 SESSION Comms setup
Between devices

End-to-end connection
4 TRANSPORT And reliability

3 NETWORK
MEDIA LAYERS

Routing of data and
Logical addressing

2 DATA LINK Physical Addressing

Media, Signals,
1 PHYSICAL Binary Transmission


Protocol layers

1 PHYSICAL LAYER

Related to bit flow (via radio, light or electric
pulses), through the network, at the electrical and
mechanical level.

It includes the definition of cables, cards.


Protocol layers

2 DATA LINK LAYER

Ethernet frame  304 bits of overhead (preamble, addresses, type, CRC)
 data block: from 46 to 1500 bytes

Inter frame gap  (IFG) 96 bits of “spacing” between packets (minimum)

(100BaseT)

Related to aggregation of bits in data packets. It includes error handling at the
physical level and frame synchronization.


Ethernet frames
Bitrate 100%
Number of
Usage samples in usec
payload @48kHz

Assumptions:
Assumptions: 12 250.0
• 100BaseT
• 100BaseT 50%
• 48 kHz SR
• 48 kHz SR
• 24-bit samples 3 62.5
• 24-bit samples !! 32%
• Ethernet frames
• Ethernet frames
(no IP)
(no IP)
• NO aux data
• NO aux data !! 11% 1 20.8
0%
1 16 32 48 64 80 Number of channels in payload

 1-sample buffer, 1 to 15 audio channels need 32% of the bandwidth!!
 3-sample buffer, 1 to 5 audio channels need 11% of the bandwidth!!


Protocol layers

3 NETWORK LAYER

It offers data packets switching e routing methods,
through the creation of paths to transmit data
from one node to the other(s).

It includes routing, forwarding, addressing,
internetworking functionalities, error handling,
congestion control.


Data traffic optimization for AoE

Cluster with many
 optimal bandwidth usage
channels and low latency

Cluster with few channels
 optimal bandwidth usage
and higher latency


Ethernet – Evolution of
OSI
Layer 1 Protocols i.e. A-Net, REAC, Rocknet,
AES50

Layer 2 Protocols i.e.EtherSound, CobraNet

Layer 3/4 Protocols i.e. Dante, Livewire, Q-Lan / Q-
Sys, RAVENNA,

Emerging Standards - AVB


Linear PCM
requirements
ANALOG
SIGNAL One audio channel
48 kHz 96 kHz 192 kHz
24-bit PCM
ADC 1.15 Mbps 2.30 Mbps 4.60 Mbps

Protocol
format Channels Bit rate (48 kHz) Bit rate (96 kHz)
overhead

AES/EBU 2 (48, 96, 192 kHz) 25% 3 Mbps 6 Mbps

ADAT 8 (48 kHz) 25% 12.3 Mbps 24.5 Mbps


bitrates

-- MADI --
56 ch 64 ch

-------------- AES3 --------------
192 kHz ADAT
44.1 kHz 48 kHz 96 kHz


Linear Video
Requirements
3G-SDI

raw
720p
HD-SDI
CC

SD
CC

I
R-

MADI
-S
I

60
R-

D
(PA

60

I
1

64 ch
L)

1

@48 kHz


bitrates
1080p (fullHD)
1920 x 1080
4:4:4, 8-bit, 60 fps 3G-SDI

1280 x 720
4:4:4, 8-bit,
60 fps raw
720p

720 x 486
4:2:2, 8-bit, HD-SDI
29,97 fps
CC

SD
CC

I
R-

MADI
-S
I

60
R-

D
(PA

60

I
1

64 ch
L)

1

@48 kHz


Audio-over-Ethernet


Audio-over-Ethernet
Cobranet
• designed on 10 Mbps networks in the 90s, compatible with modern networks
• sync propogation (audio clock) with beat packets
• over 1 million nodes installed worldwide
• designed in USA by Peak Audio
• available as an OEM module
• the technology has been acquired by a silicon foundry
• now available on a single chip
• switch-compatible protocol
• non-audio data traffic can interfere
• latency = 1.33-5 ms, allows routing of low-channel count clusters (bundles)


Audio-over-Ethernet
Ethersound
• designed for 100 Mbps networks
• uses all the available bandwidth, to transfer the maximum number of channels
• designed for maximum reliability and minimum latency (125 us)
• designed in France by Digigram
• available and an OEM module and under license
• compatiile with some switches (verified by the technology provider)
• does not allow simultaneous non/audio data traffic


Audio-over-Ethernet
AES50, HyperMAC

• designed by Sony Oxford labs
• adopted by Midas / Klark Teknik
• now promoted by Midas/KlarkTeknik
• AES50: audio and clock transmission over cat5 and 100BaseT
• 48x48 ch @ 48 kHz
• 24x24 ch @ 96 kHz
• HyperMAC: 256x256 ch on 1000BaseT


Audio-over-Ethernet
Dante
• designed for 1 Gbps networks, external branches can go at 10 Mbps
• clock recovery is based on packet timestamping (IEEE-1588)
• compatible with non-audio traffic (switches need management configuration)
• designed in Australia by Audinate
• available as an OEM module
• native driver on host
• high-performance PCI-Express card available (128x128 ch at 96 kHz)


Host audio driver
(Mac, Win)

ASIO / CoreAudio

You need at least one hw
device in the network

Latency = 4, 6 or 10 ms
24-bit audio

Max channel count

Ethernet 48 kHz 96 kHz
port 24-bit 24-bit

100 Mbit 32x32 16x16

1 Gigabit 64x64 32x32


Audio-over-Ethernet
Partial List of Dante Implementors
Allen & Heath Auvitran
BOSCH
DiGiCo
Dolby
EV
Focusrite
LAB.GRUPPEN
Lake
Link
Media Matrix
TEQSAS
TurboSound
Whirlwind
Yamaha

How Many More RJ45
Jacks…?


The Digital Challenge


Digital Networking
Today
The Current State of the Industry
Transport Protocol Wars, It’s a Mess with
HOPE!
Many are Proprietary
Lack of easy digital interoperability
Require multiple cabling topologies and
disparate signal types
Non Standard or Specialized Equipment
Remote Control & Monitoring for is a
Completely Separate Issue (Open Control
Alliance)

The Digital Challenge
AES-EBU MADI CobraNet EtherSound Dante AVB

75 Ohm With SD
Digico x Demo
Coax Rack

Avid
75 Ohm
Venue x x
Profile Coax

Soundcraft
Vi
x CAT5/7 CAT5 CAT 5 x x

Yamaha
M7 CL ES
x MY MY Native MY

Yamaha
New CL
x MY MY MY Native Demo


Solution Examples


Some “Real World” Experience

AES/EBU Drive + Canbus D&B
PM1D, Link Yamaha system
Midas Pro6 AES50 & HyperMAC
Avid Venue with 6x75 Cable
PM5D, Dante, Dglink,
M7CL ES, EtherSound / Dante
DGLink, LabGruppen
Digico SD7, SD Rack, 6 x75 Cable
Video solutions


CS1D/DSP1D

 50 Ohm Coax
Control

 75 Ohm Coax Word
Clock

 8 – AES-EBU

 34 Pair 26 AWG SCSI


AES Drive & Remote

 6 / 12 / 24 AES-EBU

 2 CAT6

 LKA 54 or 85 Pin
Connector


MADI with Multicore


Dual PM5D
Ethersound


LS9-32 Dante


M7CL Hybrid
ES/Dante


AES50 & HyperMAC


AES50 & HyperMAC
Nobel Peace Prize 2008, Oslo


Redundant Dante with LabGruppen PLM
Series Amplifiers

PRI

SEC


What about Video?


“Mixed” Environment


Recent Activity


Olympic Handover, London

HP Procurve
2524 switch
24-pt 10/100
Mbit

Cisco Catalyst
3500 switch
8-pt Gigabit

40000 people

One-day event at The Mall park

AudVidBridge &
Dante


Recent AVB
Conference
• The Live World - Jim Risgin -
Onstage Audio
• “Talkers & Listeners”
• It’s all about “Channels & Stream
Reservation”
• “Easy & Just Works”
• “Instant Discovery”
• “We’ve Taken the configuration out of
the picture”
• “Transport is Easy” DSP Remote Control
is a different story


“Help is on the Horizon!”
One Perspective from the Real World
One Perspective from the Real World

QuickTime™ and a
decompressor
are needed to see this picture.


Recent AVB
Conference
• The Integrator’s World -
Vickram Kirby - Thinkwell
Designs
• Clocking has historically been the biggest
challenge
• Interfacing & Interoperability without a
“per port” license fee
• “Learn how to use Wire Shark!”
• Still using VLANS to “Harden” our
network (53 VLANS of Cobranet)
• Configure a spare port for every VLAN


What to Expect
Hold on for the Ride
Hold on for the Ride
• Open Control Alliance (OCA)
“the other piece of the puzzle”
• Dante is a viable Solution
Available Today and will be
Future Compatible with AVB
• AVB / AVnu Alliance will gain
traction but may not be as
“Open” as reported
• Link will Continue to Track &
Support Multiple Options

Digital Audio Networking

THANK YOU
Umberto Zanghieri – ZP Engineering S.r.l.
Bob Vanden Burgt - Link USA
• bob@linkusa-inc.com
Slides & References
www.linkusa-inc.com


Practical Applications for Digital Audio Networking

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