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7-76 Compression Technologies for Audio

Table 7.3.2 Language Code Table for AC-3 

(

After [4].)

Code

Language

Code

Language

Code

Language

Code

Language

0x00

unknown/not appli-
cable

0x20

Polish

0x40

background sound/
clean feed

0x60

Moldavian

0x01

Albanian

0x21

Portuguese

0x41

0x61

Malaysian

0x02

Breton

0x22

Romanian

0x42

0x62

Malagasay

0x03

Catalan

0x23

Romansh

0x43

0x63

Macedonian

0x04

Croatian

0x24

Serbian

0x44

0x64

Laotian

0x05

Welsh

0x25

Slovak

0x45

Zulu

0x65

Korean

0x06

Czech

0x26

Slovene

0x46

Vietnamese

0x66

Khmer

0x07

Danish

0x27

Finnish

0x47

Uzbek

0x67

Kazakh

0x08

German

0x28

Swedish

0x48

Urdu

0x68

Kannada

0x09

English

0x29

Turkish

0x49

Ukrainian

0x69

Japanese

0x0A

Spanish

0x2A

Flemish

0x4A

Thai

0x6A

Indonesian

0x0B

Esperanto

0x2B

Walloon

0x4B

Telugu

0x6B

Hindi

0x0C

Estonian

0x2C

0x4C

Tatar

0x6C

Hebrew

0x0D

Basque

0x2D

0x4D

Tamil

0x6D

Hausa

0x0E

Faroese

0x2E

0x4E

Tadzhik

0x6E

Gurani

0x0F

French

0x2F

0x4F

Swahili

0x6F

Gujurati

0x10

Frisian

0x30

reserved

0x50

Sranan Tongo

0x70

Greek

0x11

Irish

0x31

"

0x51

Somali

0x71

Georgian

0x12

Gaelic

0x32

"

0x52

Sinhalese

0x72

Fulani

0x13

Galician

0x33

"

0x53

Shona

0x73

Dari

0x14

Icelandic

0x34

"

0x54

Serbo-Croat

0x74

Churash

0x15

Italian

0x35

"

0x55

Ruthenian

0x75

Chinese

0x16

Lappish

0x36

"

0x56

Russian

0x76

Burmese

0x17

Latin

0x37

"

0x57

Quechua

0x77

Bulgarian

0x18

Latvian

0x38

"

0x58

Pustu

0x78

Bengali

0x19

Luxembourgian

0x39

"

0x59

Punjabi

0x79

Belorussian

0x1A

Lithuanian

0x3A

"

0x5A

Persian

0x7A

Bambora

0x1B

Hungarian

0x3B

"

0x5B

Papamiento

0x7B

Azerbijani

0x1C

Maltese

0x3C

"

0x5C

Oriya

0x7C

Assamese

0x1D

Dutch

0x3D

"

0x5D

Nepali

0x7D

Armenian

0x1E

Norwegian

0x3E

"

0x5E

Ndebele

0x7E

Arabic

0x1F

Occitan

0x3F

"

0x5F

Marathi

0x7F

Amharic

intended to reproduce these channels. SMPTE 320M specifies a mapping between the audio sig-
nals intended to feed loudspeakers, and a sequence of audio tracks on multitrack audio storage

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DTV Audio Encoding and Decoding

DTV Audio Encoding and Decoding 7-77

media. The standard also specifies the relative levels of the audio signals. Media prepared
according to the standard should play properly on a loudspeaker system calibrated according to
RP 173.

In consumer audio systems, the LFE channel is considered optional in reproduction. Media

that conform to SMPTE 320M should be prepared so that they sound satisfactory even if the
LFE channel is not reproduced. When an audio program originally produced as a feature film for
theatrical release is transferred to consumer media, the LFE channel is often derived from the
dedicated theatrical subwoofer channel. In the cinema, the dedicated subwoofer channel is
always reproduced, and thus film mixes may use the subwoofer channel to convey important low
frequency program content. Therefore, when transferring programs originally produced for the
cinema over to television media, it may be necessary to remix some of the content of the sub-
woofer channel into the main full bandwidth channels.

7.3.7

References

1.

Fibush, David K.: A Guide to Digital Television Systems and Measurements, Tektronix,
Beaverton, Ore., 1997.

2.

SMPTE Standard for Television: “12-Channel Serial Interface for Digital Audio and Auxil-
iary Data,” SMPTE 324M (Proposed), SMPTE, White Plains, N.Y., 1999.

3.

ATSC, “Digital Audio Compression Standard (AC-3),” Advanced Television Systems
Committee, Washington, D.C., Doc. A/52, Dec. 20, 1995. This document is included on the
CD-ROM.

Table 7.3.3 Typical Bit Rates for Various Services 

(

After [4].)

Type of Service

Number of Channels

Typical Bit Rates

CM, ME, or associated audio service containing all nec-
essary program elements

5

320–384 kbits/s

CM, ME, or associated audio service containing all nec-
essary program elements

4

256–384 kbits/s

CM, ME, or associated audio service containing all nec-
essary program elements

3

192–320 kbits/s

CM, ME, or associated audio service containing all nec-
essary program elements

2

128–256 kbits/s

VI, narrative only

1

48–128 kbits/s

HI, narrative only

1

48–96 kbits/s

D

1

64–128 kbits/s

D

2

96–192 kbits/s

C, commentary only

1

32–128 kbits/s

E

1

32–128 kbits/s

VO

1

64–128 kbits/s

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DTV Audio Encoding and Decoding

7-78 Compression Technologies for Audio

4.

ATSC, “Digital Television Standard,” Advanced Television Systems Committee, Washing-
ton, D.C., Doc. A/53, Sept.16, 1995. This document is included on the CD-ROM.

5.

ITU-R Recommendation BS-775, “Multi-channel Stereophonic Sound System with and
Without Accompanying Picture.”

6.

ATSC, “Guide to the Use of the Digital Television Standard,” Advanced Television Sys-
tems Committee, Washington, D.C., Doc. A/54, Oct. 4, 1995. This document is included on
the CD-ROM.

7.

ATSC, “Digital Audio Compression Standard (AC-3), Annex A: AC-3 Elementary Streams
in an MPEG-2 Multiplex,” Advanced Television Systems Committee, Washington, D.C.,
Doc. A/52, Dec. 20, 1995. This document is included on the CD-ROM.

8.

SMPTE Standard for Television: “Channel Assignments and Levels on Multichannel
Audio Media,” SMPTE 320M-1999, SMPTE, White Plains, N.Y., 1999.

7.3.8

Bibliography

Ehmer, R. H.: “Masking of Tones Vs. Noise Bands,” J. Acoust. Soc. Am., vol. 31, pp. 1253–1256,

September 1959.

Ehmer, R. H.: “Masking Patterns of Tones,” J. Acoust. Soc. Am., vol. 31, pp. 1115–1120, August

1959.

Moore, B. C. J., and B. R. Glasberg: “Formulae Describing Frequency Selectivity as a Function

of Frequency and Level, and Their Use in Calculating Excitation Patterns,” Hearing
Research, vol. 28, pp. 209–225, 1987.

Todd, C., et. al.: “AC-3: Flexible Perceptual Coding for Audio Transmission and Storage,” AES

96th Convention, Preprint 3796, Audio Engineering Society, New York, February 1994.

Zwicker, E.: “Subdivision of the Audible Frequency Range Into Critical Bands (Frequenzgrup-

pen),” J. Acoust. Soc. of Am., vol. 33, p. 248, February 1961.

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DTV Audio Encoding and Decoding

8-1

Section

8

Audio Networking

Network communication is the transport of data, voice, video, image, or facsimile (fax) from one
location to another achieved by compatibly combining elements of hardware, software, and
media. From a business perspective, network communications is delivering the right information
to the right person at the right place and time for the right cost. Because there are so many vari-
ables involved in the analysis, design, and implementation of such networks, a structured meth-
odology must be followed in order to assure that the implemented network meets the
communications needs of the intended business, organization, or individual.

For an audio facility, the starting point is the business-level objectives. What is the company

trying to accomplish by installing this network? Without a clear understanding of business level
objectives, it is nearly impossible to configure and implement a successful network.

After business objectives are understood, the applications  that will be running on the com-

puter systems attached to these networks must be considered. After all, it is the applications that
will be generating the traffic that will travel over the implemented network.

After applications are understood and have been documented, the data that those applications

generate must be examined. In this case, the term “data” is used in a general sense as today’s net-
works are likely to transport a variety of payloads including voice, video, image, and fax in addi-
tion to “true” data. Data traffic analysis will determine not only the amount of data to be
transported, but also important characteristics about the nature of that data.

Given these fundamental requirements, the task is to determine the specifications of a net-

work that will possess the capability to deliver the expected data in a timely, cost-effective man-
ner. These network performance criteria could be referred to as what the implemented network
must do in order to meet the business objectives outlined at the outset of the process. Such
requirements are known as the logical network design.

In This Section:

Chapter 8.1: Network Concepts

8-5

Introduction

8-5

OSI Model

8-5

Physical Layer

8-6

Data Link Layer

8-7

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Source: Standard Handbook of Audio and Radio Engineering

8-2 Section Eight

Network Layer

8-8

Transport Layer

8-8

Session Layer

8-8

Presentation Layer

8-9

Application Layer

8-9

Network Classifications

8-9

References

8-10

Bibliography

8-10

Chapter 8.2: Serial Digital Video/Audio Systems

8-11

Introduction

8-11

Serial Digital Interface

8-11

Embedded Audio

8-12

Error Detection and Handling

8-13

Packetized Data Transport

8-14

Optical Interconnect

8-15

High-Definition Serial Digital Interface

8-15

A Practical Implementation

8-17

Audio Interface Provisions

8-20

MPEG-2 Audio Transport

8-23

Data Services

8-23

Time Division Multiplexing on SMPTE 292M

8-24

Packet Transport

8-25

540 Mbits/s Interface

8-26

Serial Data Transport Interface

8-27

SDTI Data Structure

8-27

SDTI in Computer-Based Systems

8-29

SDTI Content Package Format

8-30

SMPTE 326M

8-30

Data Packet Encapsulation

8-32

Timing Issues

8-33

MPEG Decoder Templates

8-33

References

8-33

Bibliography

8-34

Chapter 8.3: Video/Audio Networking Systems

8-35

Introduction

8-35

Architecture of ATM

8-35

ATM Cell Structure

8-37

IEEE 1394

8-39

Operating Modes

8-39

Data Rates and Cable Lengths

8-39

Isochronous and Asynchronous Transmissions

8-40

Fibre Channel

8-42

Gigabit Ethernet

8-42

Network Bottlenecks

8-44

A Network Solution

8-44

Quality of Service

8-45

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Audio Networking