The first format that was created for
CDs was the audio CD. It was meant to
succeed the vinyl record as a method for
storing and playing music and was called
the Compacy Disc Digital Audio.
Cassettes and records were the primary
methods of carrying audio, but they had
problems that were addressed with the
help of CDs. The quality of the vinyl on
the record could degrade as you kept
playing it back, which could lead to
lower sound quality, which CDs fixed.
The "Red Book," so named because of the
color that the cover sports, shows that
the medium standard for your typical
Compact Disc is meant to carry a
frequency range of 20Hz to 20kHz, and
two channel 16-bit PCM encoding is used
to convey the audio, giving it a high
standard for quality. While cassette
tapes or records usually have monaural
recordings, you could not do that with
CDs, so mono tracks were just presented
as two channels that sounded identical.
Though the Red Book Standard claims that
you can use four channel sound,
commercial CDs have not used this;
instead DVD audio is usually the
standard for that particular format.
When CDs first came into prominence,
they were resisted at first by music
aficionados that touted the superior
sound quality of vinyl, which is
something that some people still hold to
today. The origin of this belief stems
from the fact that early CDs used the
cost cutting measure of having 14-bit
digital-to-analog converters in lieu of
the usual 16-bit ones, but that is in
the past. Though technology has caught
up, the discussion still rages as to
which is better, vinyl or CD.
Compact Discs
A CD is a format that uses an optical
disc to carry data in a digital format.
Sony and Philips created this particular
format together in 1980; it was meant to
replace the vinyl record and provide a
more secure method of carrying data. As
they first looked into creating this
design, they wanted to look at a 60
minute playing time for that format.
Norio Oga, the vice president of Sony at
the time, thought about that particular
time limit so it would fit the 1951
recording of Beethoven's Symphony #9. In
later years, 80 minutes became the new
time limit.
As the time passed, the format would
expand and further itself, with CD-ROMS
that could carry computer data to VCDs
and SVCDs, which are video compact discs
that could hold interactive media and
photos as well, providing new ways to
use the medium. Though the CD has been
around for more than two decades, it is
still the primary media for audio files.
CD-i
Interactive media uses this type of CD.
This had audio on it, but the first
track instead held extra information
which would not be displayed on the
table of contents for the CD. So when it
was placed in a regular CD player, it
would not play that track.
Though CD-i did not last long, it was
used mostly for children's games and
interactive coloring books.
CD-Text
The Red Book Standard also talks about
CD-Text, which is a format that includes
the audio tracks, along with text that
provides the artist, track and album
names. Though this feature is typical in
most CDs now, there are some disks or
hardware that does not use this. More
and more new cars are including this
feature in order to show data about your
CDs. CD+Graphics (CD+G) and CD+ Extended
Graphics (CD+EG/CD+XG)
These formats have data on the audio,
both in text format and in picture
format, so you have more data on your
tracks. While they operate normally in
regular CD players, if you have a unique
player you will be able to see added
graphical information. For the most
part, karaoke machines use these formats
to display the lyrics so you can follow
along.
CD-ROM
When the CD first came out, audio
playback was its only purpose. However,
five years after its release, Philips
and Sony thought they could use the same
medium to display computer information.
If you had a CD-ROM drive on your
computer, you could play DVD-ROM disks.
Video CD(VCD) and Super Video CD (SVCD)
When the VCD and SVCD came out, they
were the primary method of viewing video
from a CD, and both DVD players and VCD
players could use them. With VCDs, you
could get VHS-level quality on the
video, with improved visuals on the SVCD.
Picture and Photo CDs
Kodak developed the CD for use as a data
storage medium to put your photos on,
calling them Picture and Photo CDs.
While they sound similar, there are
significant differences in these two
formats. With the Photo CD, you can hold
100 images of high quality images; the
Picture CD, however, you can place far
more images on them, but they are
compressed JPEGs.
SACD (Super Audio CD)
This format is like the regular CD-DA,
but the audio is at a much higher
resolution, making the sound far better
than a typical CD. With the advent of
DVD-Audio, SACDs were created in order
to combat its popularity, though the
fact remains that DVD Audio did not
catch on very well.
With an SACD, you will also be able to
have a hybrid disc that includes both
regular CD and SACD audio, giving you
two options for quality on your tracks.
That feature also permits you to play
these SACDs in regular CD players and
still hear the tracks.
CD-R (CD Recordable)
CD-Rs are CDs that have a photosensitive
dye that the data spiral receives in the
manufacturing process. The CD burner
will then use a laser to alter the dye's
color, imparting the information and
giving it the ability to be played in a
regular CD player, so its read laser can
interpret the information.
While CD-R burns are intended to put the
information on the disk forever, there
is research that indicates, that the
media will be unreadable over time.
Though a physical CD can endure for up
to a century, you might not have the
same time frame with the information
placed on it, due to the quality of the
disk, how you store it, or how well the
drive works. There are even tests that
indicate an 18 month shelf life for
burned CDs, especially if you do not
take good enough care of your CDs.
CD-RW (CD Rewritable)
Compared to colored dyes in CD-R, CD-RWs
use metallic allow to carry their
information. When the write laser is
used in the burner, the alloy is heated
up in order to make the allow reflect
the information on the disc. In this
manner, it is turned into a typical CD
and it can store the data.
Enhanced CDs
Enhanced CDs were utilized to put extra
computer-related information onto an
audio CD, thereby increasing the value
of their music discs. If you had a
CD-ROM drive, you could access unique
features and data on your computer.
Once computers started to get more
prevalent in the late 90s, more Enhanced
CDs were created. Once Iron Maiden
started to remaster their albums, they
made their rereleases Enhanced CDs.
CD Recording
If you want to put data of your own onto
a CD, there are many ways in which you
can do it. There are CD-R, which
necessitate making a permanent copy of
your data, or CD-RWs, which allow you to
rewrite and overwrite as you see fit.
DVDs
Much like a CD, a DVD, or Digital
Versatile Disc, is a format meant to
store digital data. It can store both
video and audio, as well as normal
computer information. Though DVDs and
CDs may look nearly identical on the
surface, DVDs have a much greater
storage capacity. While CDs were
expanded to provide a plethora of
formats used for different purposes,
DVDs have only yielded
DVD Video and DVD Audio.
DVD-RAM
DVD-Random Access Memory is utilized
mostly to back up data for computers in
the event of an emergency. Compared to
DVD writable and rewritable formats,
DVD-RAM is far more efficient and
durable due to the defect management
capabilities and error control
integrated into the medium. What's more,
data can last much longer on a DVD-RAM,
and has a greater capability of being
rewritten than RW discs on the whole. If
you want to store data for a long time,
this is the preferred method.
DVD-R and DVD+R
Both of these formats are fairly similar
in their purpose, but they do the same
job in fairly different ways, making
them quite dissimilar. They work not
unlike recordable CDs in that dyes are
used to store the information. Whatever
the format, you are meant to put video
or data onto the disk using these dyes;
though they both do the same thing, they
do so in technically different ways,
though this is inconsequential to the
typical consumer due to the
compatibility of the formats.
Due to this lack of real difference
between consumers, there is no clear
winner on the market, so both formats
are here to stay for right now, as the
public has not decided on one or the
other.
DVD-RW and DVD+RW
Users can rewrite data onto a DVD disc
using one of these formats, which both
perform the same function They act just
like CD-RWs in that metallic alloys are
the secret to recording this
overwritable data to a DVD; also, just
like with DVD-R and DVD+R formats, both
formats are equally preferred and fairly
identical, so there is no winner on that
format. Since they are both compatible
with burners and players of DVDs, no
single format will win out.
DVD Audio
DVD-As or DVD Audio, is a method of
fitting a DVD with high quality audio
tracks. While this is a form of DVD, it
is not meant to carry video, and carries
few similarities. DVD-As do, however,
allow you to have your music in a
variety of formats from uncompressed
mono to compressed 5.1 digital surround
sound.
The year 2000 saw the release of DVD-As,
where it started to compete with SACDs.
In the end, both formats lost out to the
lasting impact of the CD.
DVD Recording
You can also record with DVDs, much like
you could with audio CDs; there are
recordable formats that you can use to
put your own data onto a DVD, such as
DVD-R and DVD+R where you can write it
once to a disc, or DVD-RW and DVD+RW
where you can keep rewriting, not to
mention DVD-RAM.
DVD Video
In this day and age, most people get
their digital video media in the form of
DVD. Japan brought out this product in
1996, and it started to dethrone VHS
very rapidly. While Blu-Ray format is
newer, it is still too expensive and not
widespread enough to beat DVDs except in
Japan.
With a DVD Video, you get MPEG-2 files
that are compressed to fit a movie or
television show, but the video quality
is much better than a VHS. There are
even features such as menus, chapters,
subtitles and even featurettes and extra
audio tracks you can add on.
VHStoDVD.com's content director is Keith
Gilbert, who wants to show you
how
to convert VHS tapes into a DVD format.
You can see all sorts of reviews related
to VHS to DVD recording on his website.
There is also information on how to
convert to different formats, including
DVDs, cassettes and CDs.