CAPTURE
GUIDES -> DV
capturing FAQ & myth guide
Some of this page is more
like a rant, moreso than a guide or FAQ. But the information
is important to know. When it comes to the DV format and
equipment based on DV, the ignorance surrounding it these
past few years has been thick enough to cut with a knife.
Suggested
software for "capturing" from DV
Though this author's current video
configuration is proudly DV-free, reliable sources suggest Scenalyzer
as the program to use for DV transfer. Other good
programs include DVIO,
AVI_IO,
and WinDV.
As will be explained in the myths and misconceptions area
further down the page, there is no "capturing"
done with DV, it is mere transfer of files from one device
to the next.
If you want to
convert to another format on-the-fly (like MPEG-2), use MainConcept
1.4 in capture mode. Also available from MainConcept is the
MainConcept DV codec for use with editing software like
Vegas Video and Adobe Premiere.
Common
myths and misconceptions about DV
1. DV is a single format.
"DV" was
initially the codename for a new "digital video"
format. The name stuck. Now known simply as DV, it is the
name of this single video format compression. It is not a
category in which all digital formats fall under, as in
"DV" and "analog". An MPEG file is not a
DV. An AVI file is not a DV, although a DV can be an AVI. A
DVD is not a DV. A VCD is not a DV. Understand? DV is a
digital format of video. But digital video is not
necessarily a DV.
2. You do not "capture" DV. Yes, you heard
me, you DO NOT capture DV. You TRANSFER the files. In the
world of video, the term "capture" refers to the
re-acquisition of motion images in a format that is
different from the analog source format. With DV, re-acquisition
does not occur. The information is merely transfer from
point A to point B, using special wires and software. You do
not "capture" from a DV camera any more than you
"capture" from a floppy disk. The person that
first called this process "capturing" should be
flogged for all the confusion this misused word has caused.
3. "DV" is not a wire or port. Again, DV is
the name of the video format. It is not a wire or computer
port. The wire most often used for DV transfer is called an
IEEE1394 wire, also known as "firewire".
4. A video capture card does not need "DV" to
be good. A non-DV-based video capture card has zero
relation to the DV format and the firewire cables involved
in its data transfer. In fact, it is suggested to stay away
from video cards that have had "DV ports" (merely
IEEE1394 ports) installed on the card. As was the case with
the ATI All In Wonder 8500DV, the "DV" aspect of
the card caused more problems than not (hardware conflicts). Plus the firewire
ports in use were of substandard quality. If you want to
work with DV, buy a high-quality dedicated firewire card.
5. DV-based capture "cards". A DV
capture device, like the respected external Canopus
ADVC-100, is a piece of hardware that accepts the video
signal it is given and then converts it to DV data. The DV
data is then fed to the computer. The computer can either
accept this raw DV data via DV transfer software, or the
user can choose to use a software capturing solution to
convert it to another format on-the-fly. Because of how it
works, some videographers choose to discount it as being a
true video capture card. This is because most internal
computer capture cards allow the user to select which format
the video is captured in, whereas the DV capture devices can
only hardware-capture in DV format. Even if the user decides
to software-capture the transferred data, it was already
compressed to DV by the hardware, and once compression takes
place, it cannot be undone.
6. Video camera pass-through. See previous item. This
method is identical to the DV-based capture
"cards" method, except the camera is acting in
place of the dedicated DV capture device. Cameras were never
meant to be used in this manner, so often the results can be
unsatisfactory.
7. DV is not a perfect format. In fact, it's not even
one of the best formats, it's just very popular. It's a good
VHS replacement, nothing more. The DV
format (referring to the consumer DV25 format, NTSC version)
is often criticized for not having a standardized
codec and for having hue problems. The red hues are often
overpowering, as can be the greens, causing unpleasant video
color quality. Contrast can also vary from the source. The format can also suffer from pixelation of
bright colored areas. These problems are not seen on
lesser-compressed formats. DV was a balance between editing
quality and file compression, favoring editing. MPEG is
similar in this regard, although it favors compression. It's
major drawback is the 4:1:1 compression (when discussing
NTSC users). Most other formats
use 4:2:0 and 4:2:2 and others. PAL DV uses 4:2:0 and is
therefore pretty decent.
8. An AVI is not necessarily a DV file. An AVI file
is a container format. It can hold many video formats. An
AVI can hold DV, DivX... even MPEG. Because a DV is not a
standalone format, merely a codec-based format, it must be
put inside of a container file. The container used for DV is
AVI. But an AVI is not a DV. Understand?
9. DV is not a DVD. I just had to say that one more
time. Again, DV is a single format of video compression. A
DVD is a disc type and a playback format. A DVD uses MPEG
files and audio files muxed into VOB files with IFO and BUP
navigation. DV is not at all related to a DVD.
10. DV has no relation to TBC. The DV format and a
time-base corrector has no relation. Salesmen at B&H Photo
and Video are often guilty of suggesting DV is a TBC replacement,
which is so wrong it's laughable (akin to saying a potato is
a replacement for a computer ... makes no sense whatsoever).
I hope this will get less questions asked regarding the DV
format.
Page Last Updated: May 14th 2005
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