Specifications

18
A Digital Video Primer
It is unlikely that the amount of storage that comes as standard equipment with your computer
will be adequate for your video production needs. If you intend to produce more than just very
short video clips, you’ll want to consider a storage subsystem. ere are three general scales of
subsystems, as outlined in the sidebar.
Companies that specialize in disk storage for video production applications oen rate their systems
based on the amount of video they can store. When assessing such systems, be sure to check
whether the ratings are based on uncompressed or compressed video, and if compressed, by how
much. A storage system rated for 15 hours of DV video (compressed 5:1) would only hold three
hours of uncompressed (1:1) video.
Do you need a video capture card?
With IEEE 1394 ports built into most computers these days, support for DV devices built into
editing soware, and analog-in with pass-through capability available in camcorders, if you’re
not going to be capturing much analog video, why do you need a video capture card at all?
If you are a professional editor who captures a large amount of analog footage, you will probably
be best served by investing in a good-quality capture card. Make sure your capture card provides
the capabilities you need to work with your acquisition formats. Beyond capturing, you may also
want to consider other capabilities and features:
• Some cards come with soware tools that can be used to augment the capture capabilities
found in your editing soware, cutting down capture time and saving wear and tear on cam-
corders and tapes.
• If your CPU speed is less than 3 GHz, you may not be able to take full advantage of the real-time
editing features of Adobe Premiere Pro. A number of high-end cards take over a signicant
amount of the CPU-intensive processing, so you can increase the power and speed of your
system.
• Some capture card solutions enhance the capabilities of your editing or eects soware,
enabling you to work with 3D eects or real-time HD.
• Video cards can also boost productivity when you are delivering your nished productions,
speeding up the process of rendering to a variety of formats.
Six basic features dene video capture cards:
• Types of analog video input/output supported
• Types of digital video input/output supported
• Types of video compression supported
• Types of special processing supported
• Types of soware included or supported
• Types of audio supported
Your choice will depend on the type of video and how much video you will be working with, as
well as how time-critical your workow is. Other factors may include cost and compatibility.
STORAGE SUBSYSTEMS
Individual external hard disks, available in the
hundreds-of-dollars range, can now hold over 500GB
of data. They are typically small and compact, usually
quite portable, and take advantage of convenient
hot-swappable IEEE 1394 or USB 2.0 interfaces. Such
drives provide excellent and aordable “sneakernet”
solutions that can be physically picked up and moved
from one workstation to another.
RAID (redundant arrays of independent disks) is
fast, fault-tolerant, and relatively expensive, typically
costing from just under a thousand to thousands of
dollars. A RAID consists of multiple hard disks, which
appear to the workstation operating system as a
single volume. RAID is a technology that species at
least 10 dierent ways to coordinate multiple disks,
each method optimized for dierent types of storage
requirements. Because all the disks in a RAID can read
and write simultaneously, a RAID can access and
deliver information faster than a single hard disk.
Most RAID congurations also store parity informa-
tion to reconstruct lost data in the event of a crash.
RAIDs may be connected to workstations via IEEE
1394, SCSI, or ber channel interfaces.
A storage area network (SAN) is a centralized stor-
age subnetwork that can provide terabytes of storage
and be simultaneously accessed by multiple users. A
SAN may be JBOD (just a bunch of disks) or composed
of multiple RAIDs. Data may be accessed in real time
and at very high speeds, most often via ber channel
interfaces or SCSI, although IEEE 1394-based SANs are
available. Anyone with authorization can access any
digitized content on the SAN, so the need for multiple
copies of large media les is eliminated, thereby mak-
ing this a very ecient solution for large production
facilities and workgroups. Depending on the software
interface, the administration of a SAN may be done
remotely, providing incredible exibility to mobile
workgroups among which workow must be reorga-
nized on the y. With the ever-increasing demand for
more digital video content, SANs are becoming more
common, even in smaller production environments.