In This Issue

Vol. 1, No. 1

> Editor’s Notes

> Digital Insecurity? An introductionand overview on the state of security in the digital audio industry.

> Where does flash memory fit in?

> Tech Talk: The anatomy of a DSP-based multi-format digitalaudio player.

> Hot off the Presses: TI’s latestindustry news.

As a major player in the portable

digital audio player industry,

Texas Instruments provides

consumer electronics manufacturers

with a complete hardware and

software solution for these players.

In fact 8 of the top 10 consumer

electronics manufacturers have chosen

a TI Digital Signal Processor (DSP)

solution for their players. That is more

than any other programmable chip

vendor in the world.

As the leader in this industry, we

are happy to introduce “Tune In TI”.

This newsletter will explore a variety

of industry viewpoints, technical chal-

lenges and market

trends associated

with this dynamic

S E C U R I T Y

1

digital audio industry. In this

issue we’ll cover the Secure

Digital Music Initiative and

Digital Rights Management

and how these impact worldwide

digital music distribution and Internet

hotbed sites such as Napster.

We’ll address the memory and

media choices that are facing manufac-

turers and consumers alike. And we’ll

also discuss the formats and standards

in the industry. Why are there so

many… is there room for more… and

why can’t one format play all music,

voice and video?

In addition, you will hear more

about the latest buzz—convergence.

What does this mean for cell phones,

personal digital assistants (PDA),

portable digital audio players, digital

cameras and other portable digital

products?

The music industry will never bethe same again.

Digital distribution has taken music,

video and the spoken word to the

next step in the evolution of the

entertainment industry. No matter

how chaotic this journey appears,

Texas Instruments’ DSP products will

be there to support these developing

technologies. We invite you to join us

as we learn from each other while we

beam down this path at light speed.

Tune

TIIN

Portable Digital Technology and Trends

As the leader in this industry, we are happy

to introduce “Tune In TI”. This newsletter will explore

a variety of industry viewpoints, technical challenges

and market trends associated with this dynamic

digital audio industry.

AUDIODIGITAL INDUSTRY

INTERNETPORTABLE

Music Initiative (SDMI) originated

in Las Vegas at Fall Comdex ’98. The

original meeting was co-sponsored

by TI and the Recording Industry

Association of America (RIAA). Since

then, SDMI membership has grown

to over 180 music content, Internet

and technology companies.

SDMI is a means by which the

international recording industry works

in sync with technology and consumer

electronics manufacturers to ensure

the secure transfer of digital audio

content across the Internet. The

initiative helps protect the rights of

recording artists by enabling copyright

protection in SDMI compliant formats.

SDMI is an “open” standard that

manufacturers can use to develop

digital audio-enabled consumer elec-

tronic devices.

The goal of SDMI is to enhance

the listening experience of consumers

by allowing them access to quality

digital music in new ways, while ensur-

ing personal portability among digital

products and services. The SDMI

specification protects copyrighted

music in all existing and emerging

digital formats.

Understand, however, that unlike

a standard such as the ATA/IDE inter-

face for hard disk drives, SDMI is not

a “standard” in the sense that most

technology companies are used to.

SDMI is not a single file format, a single

cryptographic algorithm, a single

An introduction and overview on the state of securityin the digital audio industry.

DIGITALINSECURITY

Does the Digital Audio Revolution have you feeling insecure about your content?

While the data

encryption archi-

tects are steadfastly

building the appro-

priate locks, Texas

Instruments is

working with them

to create the powerful digital keys

necessary to liberating literature

and musical content for the masses

to enjoy. TI has a complete line of

programmable DSPs specifically engi-

neered to process and decode the

multiple array of security encryption

formats that are bubbling throughout

the digital audio industry. The pro-

grammability of the DSP provides

“future proof” insurance to purchasers

of digital audio players powered by

Texas Instruments solutions. Portable

digital audio players with TI technology

can be easily upgraded to the latest

security formats and revisions right

on the Internet.

TI has been involved with the

development of digital audio security

right from the start. The Secure Digital

Some of the best data encryption

architects in the world are working

around the clock to create digital

security and Digital Rights

Management (DRM) software to

protect your digital audio content.

The fastidious development of this

security is an important step towards

the approaching boom in digital

audio sales and distribution via the

Internet and the brick and mortar

music retailers throughout the world.

2

Where does Flash Memory fit in?decoder or a single protocol specification,

nor is it designed for interoperability.

Instead, SDMI is the culmination of an

overall architecture that is a work in

progress. It consists of a set of applica-

tion layer, licensed compliant module

(LCM) layer and portable

device (PD) layer refer-

ence models and a set of

requirements governing

security, robustness and

content screening.

The leading suppliers of memory

and media cards to the portable audio

industry are also developing an addi-

tional layer of “physical” security,

and TI is stepping forward to meet

the technological integration demands

of these architectures.

Intel, Sony and SanDisk

are just three of the compa-

nies in the world who produce

flash memory modules, the

media used in over 90% of

the portable audio devices

on the market today.

Market conditions in the flash

memory business are ripe for large

price swings similar to those seen

in the DRAM business in recent

years. Several quarters of tight flash

memory demand combined with

momentous capacity expansion

could lead to price cutting due to

oversupply. There are signs in the

marketplace that flash memory

supply is catching up to demand.

This could be very good news for the

digital music industry, because there

is digital player pricing elasticity due

to the fact that 32MB and 64MB flash

modules sometimes cost more than

the players. Of course, flash memory

suppliers would love to continue seeing

fiscal quarters like they’ve

recently experienced.

Even if flash prices start

to mimic the DRAM pricing

curves of years past, the

price per MegaByte of memory is still

high enough that competitive memory

solutions such as DataPlay and Clik

have a chance to succeed in the digital

player market.

In the next issue of “Tune In TI”,

we will begin a segment called Market

Wave. This section will be dedicated

to covering issues in the digital audio

industry that have a direct impact on

consumer purchases that affect the

growth of the industry. The first

Market Wave article will focus on the

media types used by internet audio

players. For the record labels and

the consumer electronics manufactur-

ers, there are a multitude of storage

platforms and technologies to choose

from. Each platform carries a fairly

distinct set of characteristics. Some

are appealing to consumers (price)

and some are appealing to the record

labels (physical security) and so on.

We’ll take a look at hard disk drives

including the IBM microdrive Sony

Memory Stick along with the various

multi-media and compact flash cards.

And we’ll also look at the Iomega Clik

drive, the emerging storage technology

from DataPlay, and how these relate to

current CD and MiniDisc technologies.

DSPSDMIA discussion on the relationship

between TI’s DSP and SDMI technical

requirements will continue in the

next several issues of “Tune In TI”,

however, if you would like, you may

find an abundant amount of data on

the initiative at the SDMI website:

www.sdmi.orgIn addition to upcoming SDMI

technical relationship discussions,

we will feature a discussion on the

evolution of DRM in the next issue of

“Tune In TI”. Among others, Liquid

Audio, Sony, Microsoft, and InterTrust

are developing top-notch DRM SDMI

compliant software architectures for

the digital audio industry. In addition

to our existing software solutions

from Microsoft and Liquid Audio,

Texas Instruments and InterTrust

recently announced an agreement to

develop secure solutions for portable

audio devices. Solutions such as

this will allow digital content to

be securely transferred from a con-

sumer’s PC to a portable digital audio

device and used only as permitted by

the person who owns that content.

3

Decoder BasicsCurrent popular audio coding algo-

rithms use properties of the human

auditory system to achieve 10-12

times compression ratio while main-

taining near-CD quality sound. These

encoders utilize four key techniques:

auditory masking, frequency domain

coding, window

switching and

dynamic bit

allocations to

remove redun-

dancy and

irrelevancy of

raw audio data.

Auditory MaskingAdvancements in the field of

Psychoacoustics have led to much

of the breakthrough in digital audio

compression. After analyzing how

the human ear and the human mind

responds to sound, it became appar-

ent that the human auditory system

demonstrates certain masking

characteristics that can be utilized

for data compression. For instance,

there exists a quiet hearing threshold.

Signals that exist beneath this thresh-

old can be discarded without impact

to sound quality since the human

ear cannot detect such signals. Also,

when there is a presence of a strong

signal (masker), a weaker signal

(maskee) is ignored by the human ear

and may be discarded if it occurs near

the masker in the frequency domain.

Frequency Domain CodingOne very effective way of removing

data redundancies is to transform the

time domain data, which typically has

a high level of correlation, to a domain

where the components are nearly

uncorrelated. Frequency transforms

are normally used to generate a set

of spectral components, which have

very little correlation with each other,

thus removing most of the data redun-

dancies. The resultant data structure

opens up the possibility for innovative

ways of designing compression

algorithms given the fact that human

perception of audio is frequency

dependent. For example, components

that are inaudible to the human

auditory system can be isolated easily

and discarded with minimal impact

to audio quality. Popular transforms

are the Discrete Fourier Transform

(DFT) and Discrete Cosine Transform

(DCT). A hybrid transform approach

with time domain aliasing cancellation

is popular with some of the more

important digital audio compression

algorithms being used today.

Continued on pg. 5 >

techtalkAnatomy of a Multi-Format Digital Audio Player: Digital Audio Compression Basics

The mass popularity of Napster is a clear indication of the rapidly changing

business environment for the record labels and the brick and mortar music

retailers. MP3 only songs are riding the first wave of popularity, but the

recent proliferation of new audio codecs and second-generation portable

digital players with multiple audio compression format capabilities are

changing the game.

In this issue, we begin a journey through the anatomy of a multi-format

digital audio player powered by a DSP. On this journey, we will supply

you with an introduction to the key techniques used in audio compression

technologies. And we’ll give you a thorough description of player hardware

and security technologies.

Digital

Audio

2

4

1

3Window SwitchingOne disadvantage of frequency domain

coding is pre-echoes. For example,

when there is a sudden rise in sound

amplitude after a period of silence,

it will result in a

large quantization

error. Both trans-

form and sub-band

coding will spread

this error over the

whole window in

which the domain transformation

operates. This results in the appear-

ance of very audible pre-echoes in the

time domain. One way of reducing

these echoes is to limit the error to a

shorter time frame (shorter window),

which not only isolates other parts of

the audio from the pre-echoes, but

also allows pre-masking effects to

operate more effectively and to mask

part or all of the pre-echoes. The dis-

advantage of this approach is that it

will add to the total number of bits

needed to represent the same data

(since more side-band information is

required as the number of coded win-

dows increases). In order to achieve

the best trade off, adaptive window

sizing is implemented. Large windows

are used when signals are steady,

while smaller windows are used for

non-stationary signal

patterns with abrupt

changes in amplitude.

Dynamic Bit AllocationsIn all encoders, the final quality

depends largely on how bits are allo-

cated among the various sub-bands

or coefficients. In order to allocate the

bits efficiently, the input signal has to

be analyzed continuously and bits

assigned according to some model

derived from our knowledge of the

human auditory system. Bits are

allocated to areas that have the most

effect on human auditory perception

while those that fall in masked areas

will be allocated few or nobits for cod-

ing. Since signals are always changing

and the human auditory system reacts

to signals differently under different

situations, a dynamic bit allocation

technique is required. An accurate

model of how humans perceive sounds

is the main characteristic of a good

bit allocation scheme.

Reference

[1] Thomas Sikora, “MPEG Digital Audio- and

Video-Coding Standards”, IEEE Signal Processing

Magazine, September 1997.

[2] Jason Kridner, Mark Nadeski and Pedro Gelabert,

“A DSP Powered Solid State Audio System”, Texas

Instruments Incorporated, 1999.

[3] Khalid Sayood, “Introduction to Data

Compression”, Morgan Kaufmann Publisher, Inc. 1996.

[4] ISO/IEC 11172-3, “Coding of Moving Pictures and

Associated Audio for Digital Storage Media at up to

about 1.5 Mbit/s, Part 3 (Audio)”, 1992.

[5] M. Bosi, K. Brandenburg, S. Quakenbush, L.

Fielder, K. Akagiri, H. Fuchs, M. Dietz, J. Hrere, G.

Davidson and Y. Oikawa, “ISO/IEC MPEG-2 Advanced

Audio Coding”, J. Audio Engineering Society. Vol 45,

No. 10, OCT 1997.

4

DynamicCode

5

Continued >ttThe typical encoderprocess is as follows:

A. The data is first segmented into

windows according to the input signal char-

acteristics, and the window of time domain

data is then transformed into the frequency

domain by transform coding (DCT/MDCT),

sub-band coding or hybrid coding.

B. The data is then quantized, (with

the number of bits allocated for each

quantizer depending on the human auditory

system model applied) followed by some

form of entropy coding to remove symbol

redundancies.

C. The data streams are typically

multiplexed with header and various side-

band and ancillary information to form the

final bitstream. The decoding process is

the reverse of the encoding process but is

much simpler since no psychoacoustic

model analysis is required.

D. The audio data is extracted from

the bitstream and passed through entropy

decoding, dequantization and frequency

to time transformation to obtain the

final output.

We will apply the final output, a sample piece of audio data, to a secure DSP based hardwareplatform in the next issue of “Tune In TI”.

Toshiba uses TI’s DSP in newMobile Audio PlayerIn May Toshiba announced they are

using TI’s low-power, industry-leading

programmable DSP to power their

new Mobile Audio Player, MEA110AS.

The Toshiba player is the world’s first

to offer a Secure Digital (SD) memory

card slot supporting storage of copy-

righted content. For more info, see:

www.ti.com/sc/docs/news/2000/00087.htm

TI and InterTrust security solution in developmentIn an effort to accelerate the growth

of the Internet audio market, TI

and InterTrust Technologies Corp.,

announced an agreement to develop

secure solutions for

portable audio devices.

This solution will allow

digital content to be

securely transferred

from a consumer’s PC to a portable

Internet audio device and used only

as permitted by the rightful owner

of the content. For more info, see:

www.ti.com/sc/docs/news/2000/00075.htm

Sony uses TI DSP in VAIO®

Music Clip™ playerSony selected the low power, industry-

leading programmable DSP developed

by TI for its sleek VAIO

Music Clip Internet audio

player. The VAIO Music

Clip using TI’s DSP, allows

consumers to experience

up to five hours of contin-

uous high quality music on one

AA battery. For more info, see:

www.ti.com/sc/docs/news/2000/00041.htm

T I ’ S L A T E S T I N D U S T R Y N E W S

Market Wave: Confused aboutmedia for portable players?... so is everyone else. The GreatMemory Debate is on.

Digital Rights Management discussion as part of Tune In TI’s ongoing security coverage

Tech Talk: The second of a 2 part series on the anatomy of a DSP based multi-format digital audio player.

Hot off the Presses: Featuring anewly released TI DSP-powereddigital audio player that’s worth a look.

Registration and access to allissues: www.ti.com/sc/tuneinti

Editor: Chris Schairbaum (c-schairbaum@ti.com)

Contributors: Oh Hong Lye, Bob McKune, Randy Cole, Jennifer Walker, Chrisann Cook

All products are trademarks of theirrespective companies.

Next issue of Tune In TI will include:

off the Presses

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