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 ([email protected])
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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