Specifications
12
A Digital Video Primer
A few words about analog video connections
e music industry has already converted to digital. Most music today is mastered, edited, and
distributed in digital form, primarily on CD and via the web. While video today is generally
captured digitally, it doesn’t mean that you can ignore the analog video world. Many professional
video devices are still analog, as well as tens of millions of consumer cameras, tape devices, and
of course, televisions. You should understand some of the basics of analog video.
Because of the noise concerns mentioned on page 1 of this primer, in analog video the connection
between devices is extremely important. ere are three basic types of analog video connections.
Typically, the higher the quality of the recording format, the higher the quality of the connec-
tion type.
• Composite: e simplest type of analog connection carries the complete video signal over a cable
with a single wire. e luminance and chrominance information is combined into one signal using
the NTSC, PAL, or SECAM standard. ough this is the most common type of connection, composite
video has the lowest quality because of the amount of processing required to merge the two signals.
• S-Video: e next higher quality analog connection is called S-Video. is cable separates the
luminance signal onto one wire and the combined color signals onto another wire. e sepa-
rate wires are encased in a single cable.
• Component: e highest quality analog connection is component video, in which the Y, U, and
V signals are carried over separate cables.
Making digital video connections
Whichever interface you use for getting digital video into your computer from your camcorder
or from any digital video recording device, it’s as simple as plug-and-play.
• IEEE 1394: Originally developed by Apple Computer, IEEE 1394 is the most common form
of connection used by standard DV camcorders. Also known by the trade names FireWire®
(Apple Computer) and i.LINK (Sony Corporation), this high-speed serial interface currently
allows up to 400 Mbps to be transferred (and higher speeds are coming soon). IEEE 1394 cards
are inexpensive to add to your computer. However, most of today’s computers come equipped
with built-in ports. e single IEEE 1394 cable transmits all of the information, including
video, audio, timecode, and device control, which enables you to control a camcorder or deck
from the computer. IEEE 1394 is not exclusively used for video transfer; it is a general purpose
digital interface that can also be used for other connections, such as hard drives and networks.
• SDI: Serial Digital Interface (SDI) is the high-end professional connection for digital video. It
was originally meant for SD, but it is now also used for HD transport of uncompressed video.
SDI is typically only supported in high-end gear, although the price is dropping dramatically.
Digital video formats and camcorders
DV is oen used to denote digital video in general. However...
DV has typically been used to refer to a specic digital video format based on DV25 compres-
sion that primarily addresses the consumer and prosumer markets. e tape cassettes for this
standard DV format come in two sizes: one about the size of an audio cassette; the other, known
as mini-DV, about half that size. Standard DV is a standard-denition (SD), interlaced signal
using DV25 compression, which outputs a 5:1-compressed stream with a bit rate of 25 Mbps. For
NTSC, the color sampling is 4:1:1; for PAL, it’s 4:2:0.
When someone refers to a standard DV camcorder, they are usually talking about a digital video
camcorder that uses miniDV tape, records in the standard DV format using DV25 compression,
and has a port for connecting to a computer via the IEEE 1394 interface. DV camcorders are used
by consumers, prosumers, and even professionals shooting nonbroadcast-quality material (for
example, events like weddings and meetings.)
Digital Video terminology can be confusing. As you’ll learn by reading on, there are also varia-
tions of DV that refer to professional and broadcast-quality formats.
KNOW YOUR CABLES AND CONNECTORS
If you are new to video, guring out all of those audio
and video cables and connectors can be as dicult as
untangling a bowl of spaghetti one noodle at a time.
This chart is intended to help.
The pictured connectors (two audio and three video)
are all male; female counterparts also exist.
XLR connectors are used to
connect microphones and
other balanced audio devices
and for the AES/EBU digital
audio connection.
An RCA connector is also
called a phono plug and
is often used to connect
consumer audio and video
equipment like VCRs, tuners,
and CD players.
BNC is used to connect vari-
ous video sources, including
analog composite, analog
component, and serial digital
video interface (SDI).
The S-Video connector is for
transferring video at a higher
quality between devices that
support S-Video, like S-VHS
camcorders and video decks.
The IEEE 1394 connector (also
known as i.Link and FireWire)
is used to transfer audio
and video digitally between
a camcorder, digital tape
recorder, and computer.