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Desktop Video #1 - Video Basics and Tips
Michael Flaminio
6.25.01
About
This is a multipart series looking at desktop video on Mac OS systems. These articles
are intended to be a foundation resource for those interested in working with video
on computers. Suggestions, corrections, questions and additions are always welcome.
Digital Video Basics
There are many different kinds of digital video. Each type is encoded in a format
designed to compress the video into a usable form. Some popular formats include DV,
MPEG-1, MPEG-2, MPEG-4, QuickTime Video, Sorenson Video, Cinepak, M-JPEG and AVI.
Each format has its specialized use, and some are better than others. We'll touch
on some of the best video codecs for use in two classes of video compression. For
our purposes we'll separate desktop video into three areas, video for TV, video for
CD-ROM/Internet download and video for Internet streaming.
Digital video offers a number of advantages over analog. Digital media itself has
particular quality characteristics. Generally digital media present a crisper, cleaner
product that can be viewed an unlimited number of times. The largest advantage, however,
is that it's a lossless medium. DV can be transported an unlimited number of times
and still retain its quality. This is not true of analog video, which has a "generation"
effect each time it's transferred.
Digital Video also offers an extended shelf life. So long as the magnetic videotape
does not significantly degrade, video quality will look exactly the same today as
years from now. Because of these advantages, users can import movies into their computer,
work on them and export them back to a DV camcorder for storage. Down the road, they
can capture them back to the computer without losing any quality. So in addition
to offering good quality, DV camcorders also act as a good video backup/storage device.
Video Tips
Video is not the most spectacular of artistic formats. Compared to polished film
seen on TV and in theaters, video appears flat and grainy. One shouldn't be too alarmed
if their video looks more like bad porn than the latest Hollywood blockbuster. You're
probably not doing anything wrong. Part of the look of video is because of the equipment
quality, but also techniques.
In getting the best quality video, equipment and techniques can make a world of difference.
DV cameras differ greatly from the lower-end Sony Digital 8, to the higher-end 3
CCD MiniDVs. Even tape quality can make a significant difference. Cameras come in
numerous models and features, as I'll detail later. For now, we'll discuss getting
the most out of what you have. Here are just a couple pointers to help your video
quality:
Make sure you have ample light. Video can look grainy in shadows. Experiment with
a light meter and your camera's controls for the best situations. Also keep in mind
light sources. Lights in the camera's frame flare and ruin a good shot. Set up light
sources behind the camera. A mounted camera light can handle most close situations.
If you have a strong light sources in your frame, you may want to manipulate the
camera's iris setting to force the correct light level for the shot.
Keep it stable. Wild movements can be accentuated through video compression. Handheld
shots can be thematically effective, but keep a stable image in mind. For handheld
shots, you'll want to keep the camera's zoom wide, as that will help stabilize your
image. For tighter shots, be sure to use a tripod or some kind of mount. In general,
I always try use a tripod as much as possible.
Stay focused. If there's a lot of movement, you'll probably want to use manual focus.
Lighting changes and moving object depths distract a camera's automatic focus. If
you have a stationary object you want to focus on, have the camera auto-focus, then
turn the auto off to maintain or adjust the desired focus. Cameras vary in their
focusing abilities, so learn the limits of your equipment. General rule of thumb
states that wide-angle shots have a greater depth of field, which results in better
focus. Tighter shots require more sensitive focusing.
Get the best sound possible. You have a number of microphone options available to
you from the camera's built in mic, mounted mics or remote mics. Be sure to point
the camera's microphone at the sound source. Outdoor work can benefit greatly from
an external mic. A shotgun mic is good for picking up isolated sounds, while also
wireless mics can help get good sound while still keeping your distance. You can
even consider using an external recording device. DV uses time codes, so synchronizing
audio in postproduction can make using external recordings easier. You have the opportunity
to have CD-quality sound in your video, so you might as well get it right and make
it sound good.
These tips may seem so basic they're silly, but keeping these four things in mind
(sound, focus, stability and light) can greatly improve any project. The best suggestion
is to experiment with your camera to find the best results for your needs.
Desktop Video Tips
DV is really best for use on TV displays. The quality of DV looks fine on a TV, but
on a higher resolution computer display, things might not look so hot. In QuickTime
4, the video codec usually doesn't offer the best video image. QuickTime 4 seemed
to have some problems playing full-sized DV movies and I suspect quality is sacrificed
a bit for performance. QuickTime 5 improves on both performance and quality of its
software DV codec, so things look considerably better.
Many become frustrated at DV's quality on their computer. Keep in mind that the computer
probably won't represent how your work will look once exported to a TV. If a DV movie
looks dark or grainy, try exporting it to a TV. Using a camcorder or converter, you'll
be using the device's hardware codec, which offers a better playback option, in addition
to the fact that DV quality tends to just look better on a TV.
If you intend to save your movie for the Web or a CD-ROM, you'll need to convert
toa more appropriate codec. You will also want to reduce dimensional size of the
movie which will greatly improve the video's image. Also, many notice lines of distortion
around the edges of DV video on computers. This is normal. If you notice, a TV does
not display a margin around the video image. Again, DV is designed for TV use, so
things may not appear correctly in the margins. To fix this, you can capture your
work at 640 x 480 or smaller rather than 720 x 480. You can also trim the video to
eliminate the margins. Cleaner 5 handles trimming very well. I'm not aware of other
available tools to do this.
Next Time
Up next are the various digital video compression standards. We'll look at the most
popular video codecs, their technology and their uses.
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