Transcript Digital Media

Digital media
audio
The music industry has long been defined
by its recording media
from the earliest days of recorded sound the
emphasis has been on the medium used to
store the sound, from cylinders and paper
tape up to digital versatile discs (DVDs).
it is entirely feasible that music fans own
multiple copies of their favorite recording,
on different media — eight-track tape,
cassette tape, 33 1/3 rpm album, maybe a 45
rpm single, compact disc, and now on
DVD.
The remarkable improvement in the processing
power of computers, and the vast increase in
computer storage capacity, combined with
innovations in software that allowed digital
recording and signal processing, these factors
together began to have an impact on the
music industry.
The result was that high-quality digital
recording could be done in a basement, on
affordable equipment, at a standard that
approached or equaled commercial quality
recordings.
the music could be distributed in the same
media formats, even on compact discs,
pressed at home, “on demand”. New artists
could begin to record and market their own
music.
The historical control that labels held over
recording deals had been weakened, but the
barriers to reaching a wider audience
remained. Getting airplay on the radio and
shelf space in the stores remained as
obstacles to getting music into the hands of
fans.
the Internet provides an opportunity for artists
to reach out directly to the consumers, and
to do so in a way that integrated the
numerous segmented markets around the
country, indeed, around the world.
The potential and problems of digital audio file
distribution have been known for years.
Researchers have developed interesting mechanisms
that actually do impose controls on the distribution
of files and the means by which they can be played;
AT&T developed a system during the dot com
boom called A2B Music that embodied the
concept, but it fared poorly in the market and
ultimately faded away.
Strategies such as the A2B Music approach
work well at a prototype level, but have
never been successful in the commercial
market. Two obstacles in particular have
hindered success.
The first is that the music companies have
been reluctant to license their materials; even
Napster approached companies early in their
history in an attempt to license content, but
were rebuffed.
The second obstacle has been the reluctance of
web users to “buy into” a proprietary system
that effectively closes down all the advantages
that they have come to associate with peer-topeer file sharing—it is a difficult marketing
challenge to convince users to pay to use a
very restricted system when they have had
the experience of swapping for free.
How would a controlled distribution system
work? The concept utilizes a proprietary
media player, with a specific embedded ID
number.
When the user chooses to
download a music file, the file contains a
digital license that is unique to that copy of
the song, and specific to the individual user’s
media player.
The digital license determines the level of
rights the user has purchased. For example,
the license would allow a song to be played
once, or ten times, or indefinitely, or it
could be without restriction and thus
eligible for free swapping.
In this way, the music company could control
marketing and promotions—giving away a
swappable single, for example, to gain market
awareness, or allowing any song to be
downloaded and played one time, to see if
the user likes it, then requiring a better
license to be able to play it subsequently.
If a user swapped a digitally licensed song on to
a friend, the friend’s player would read the
digital license embedded in the song file,
and determine whether it was allowed to play
the song or not.
The combination of digital licenses and
uniquely identified media players would
effectively end the unauthorized swapping of
controlled media files--at least until a hacker
found a way to break the coding!
One strategy to popularize the approach would
be to allow free downloads of the player, and
provide a steady stream of free content to
help popularize the player. New releases
from big artists might get an advance release
through the proprietary system, thus
encouraging avid fans to hear the song first
through the system.
In this way, a critical mass of installed players
could then help launch a commercial system.
Users could choose a song from the
catalogue or a playlist, and if their license
needed upgrading, they could “click to play”
and agree to pay a small fee (charged to their
accounts) to acquire the right level of digital
license.
If designed properly, it is conceivable that
everyone would be happy. Copyright would
be protected. Creative marketing would be
possible. Artists could see auditable figures
and get their fair share of proceeds.
.
Users would get enormous content and,
given the volume, likely at a very small fee
per play, especially since the high costs
associated
with
the
manufacturing,
distributing, and warehousing of the physical
media would disappear.
Such a scheme is technically feasible, and
commercially viable, and something along
these lines will emerge in the marketplace.
Thus, the web could become the world’s
largest jukebox, but at a penny or a nickel
per play!
How are digital music files created in the first
place? How does the sound that comes from
an instrument, which is really an analog wave
form moving through the air, get saved as a
digital file that we can play on a stereo,
computer or a portable player? The analog
wave form must be converted into an
(arguably) equivalent digital form through
the use of “sampling”.
The original analog wave signal is measured or
“sampled” at regular intervals and the
measurement is stored as a 16-bit number.
The sampling rate is a big part of what
determines the audio quality, as more
frequent sampling generates more data
points, and more data points translate into
better quality of the stored signal.
The usual reference point for the quality of a digital
audio recording is that used on a compact disc.
On a CD, the music is sampled at a rate of 44,100
times per second (44.1 kHz), or roughly twice the
audio bandwidth. This means that with 16 bits
used for each sample, recording two channels (for
stereo) of music for one second requires more than
1.4 megabits of storage.
the very high sampling rate allows the sound
on a CD to be essentially indistinguishable
from the original live version for most
people.
the sound file can get pretty big: an average
three-and-a-half-minute song will take up 294
megabits, or 36.75 megabytes, of storage
space. A typical CD can store about 74
minutes of music, with a total storage
capacity of roughly 784 megabytes.
Most files on the web are measured in
kilobytes, so a single CD-quality song is
substantially bigger than an average web
page, and will take considerably longer to
download, on the scale of hours over a 56
kb modem.
In order to make downloading music on-line
even remotely feasible for the average person
on the web, something had to be done to
make those CD files smaller, but without
completely losing the original quality of the
CD recording. That something, as it turns
out, was the MP3 file format.
So where does the name MP3 come from?
The specification for digital audio files is
called MPEG, from the Moving Picture
Experts Group (the guys that created the
standard).
The MPEG group established a family of
standards designed to efficiently store
moving pictures and audio in a highly
compressed digital format. The MPEG-2
specification[1] includes three audio layers,
with varying levels of audio compression.
[1] “Generic Coding of Moving Pictures and
Associated Audio”, International Standard IS13818
Layer 1 provides compression by a factor of 4,
Layer 2 by a factor of about 6, while Layer 3
enables compression by a factor of about 10.
The MPEG specifications are fairly technical
but quite interesting; those curious are
encouraged to investigate the details via the
further reading section below.
Thus, using MPEG-2, Audio Layer 3, or MP3
for short, a song can be compressed
substantially and still retain the original CD
quality sound.
How is this possible? The short answer is that
sounds outside of human hearing range are
removed, and the remaining sound is
compressed in a manner similar to typical
file compression techniques.
The MP3 specification is an “open standard”,
which means that no one company or
individual owns the standard. Therefore,
support for MP3 is easy to incorporate into
media environments as there are no
licensing fees required.
… napster! …
The premise behind the creation of Napster
was simple: create an easy way for people to
swap MP3 format music files via the
Internet. Shawn Fanning devised a strategy
to do just that, and in spring of 1999 left
college at Northeastern University to create
the company that became known as Napster.
The strategy was fairly simple: use the
concept of peer-to-peer computing to allow
users to share files with each other. In this
way, the files are never actually stored on
the Napster file servers, just the list of users
and the files that they are willing to share.
Napster quickly became one of the most
accessed sites on the web, as an entire
generation of young people (with highbandwidth university students leading the
way) tuned in to the phenomenon.
Napster effectively bypassed the established
patterns of the music industry, which
proved to be its strength and, ultimately,
its weakness
The traditional titans of the music industry
soon focused on Napster as the very
embodiment of the threats posed by the
Internet to the music business, or, at least,
their control of the industry.
Napster did not include any sort of
mechanisms for copyright protection or
digital rights management, and this oversight
became a rather troublesome problem, as the
Recording Industry Association of America
sued the service for copyright infringement
…
… and the band Metallica famously sued, and
some recording artists also began to
recognize the threat of unfettered copying of
files.
The legal entanglements brought an end to
Napster in its original form. There are plans
for the reemergence of the service, with a
scheme for royalty payments for copyrighted
materials, but the prospects do not seem
promising.
Meanwhile, there are tens of millions of former
Napster users hungry for similar file-sharing
and music-swapping services. The demand
was met quickly by a new generation of peerto-peer file sharing systems, such as Gnutella
and Kazaa. File swapping is still ongoing,
and growing.
It is interesting to note that the original design
of Napster, wherein a list of users and their
songlists was maintained in a central site,
made it relatively easy to shut down. This
design weakness was duly noted by other
peer-to-peer systems, whose design now is
more truly distributed with no central point
of control, such that it would be quite
difficult to shut the new services down.
What Napster accomplished was to effectively
create the world’s biggest jukebox, and
provide a vivid demonstration that a new
way of doing business was not only possible
but, from the user’s point of view, far
preferable.
The technical capacity to swap files provided
the “killer application” that developers have
been seeking for years, one that took full
advantage of the Internet paradigm and
completely transformed the old way of doing
business.
an increasingly popular marketing tactic is to
for web sites to promote artists and products
by giving away selected audio tracks in the
MP3 format as a way to draw customers to
the site and (ideally) purchase the full
compact disc and related products.
Recall that in the case of downloading an
MP3 file, the file is selected and then
completely transferred and stored locally on
the user’s machine before it can be played.
There is a non-trivial delay between the
request for the song and the first time that it
can be played, as the file must be
completely downloaded before play begins.
The file remains locally stored, and thus does
not require a return trip to the original web
site to get another copy. Users effectively
possess the copy, and can play it
independently of the original server, or swap
it with their friends.
In the case of streaming media, the song is
requested from the server and the transfer
begins. The first portion of the song is
buffered locally, in Random Access
Memory, and starts playing before the entire
transfer is complete
The song is stored only in the buffer,
temporarily, and is not saved onto the local
disk. The significance is that streaming
media files must be played from the source,
every time, and can’t be saved or swapped by
the user. If the users want to hear the song
again, they must return to the original site
and request it.
A timeline of major events in the history of
recorded music can be found at
http://history.acusd.edu/gen/recording/notes.ht
ml.
A good starting point for MPEG facts and
references
can
be
found
at
http://www.mpeg.org.
The music file sharing services mentioned can
be found at:
- Napster http://www.napster.com
- Gnutella http://www.gnutella.com
- Kazaa
http://www.kazaa.com