Introduction to DV: Capture FAQ and Myth Guide
Although some of this page is more like a rant than a guide, the information is important to know. When it comes to the DV format and equipment based on DV, the ignorance surrounding it the past decade has been thick enough to cut with a knife. Though this author’s current video configuration is proudly DV-free, I submit the following valuable information for your DV needs.
Suggested Software for Capturing from DV Tapes
The best software for capturing DV tape — or more accurately, “transferring” DV off the tape and onto the computer (more on that below) — is either the freeware software Scenalyzer 3.5 or the freeware WinDV. The payware Scenalyzer Live 4.0 is another excellent choice. AVI-IO and DVIO are two more often-suggested choices from past years.
What you don’t want to use for capture/transfer is a fancy editor like Adobe Premiere or Sony Vegas. Indeed, these resource-hungry editors from companies like Adobe, Sony, Corel, Ulead, Cyberlink and Pinnacle make for lousy DV capture/transfer utilities. You’ll often run into dropped frames or other problems, so it’s best to leave editors purely for the editing. You can just as easily import a captured DV later, and without risking lost time (due to bad captures that must be dumped and redone). Software that comes with Windows, such as Windows Movie Maker, is also not suggested.
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), you’ll have to use software like VirtualDub with the Matrox MPEG-2 codec. Or possibly a deprecated program like MainConcept 1.4 in capture mode.
DV FAQ – Clearing Up Common Myths & Misconceptions
1. Is 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 in 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. You simply 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 400.
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 and boxes. 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. However, 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. A DV transfer card is hardware-locked to encoding only to DV.
6. Video camera pass-through. See previous item. This method is identical to the DV-based capture card method, except the camera is acting in place of the dedicated DV capture device. DV cameras were not necessarily meant to be used in this manner, so the results can vary.
7. DV is not a perfect format. In fact, it’s not even one of the best formats, it’s just very popular. As a shooting format, 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 chroma issues because of colorspace compression. This can present itself in several ways, such as red or green hues being pumped up and fake looking, 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 colorspace 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. Remember that DV was invented in the age of Pentium III CPUs and 500MB hard drives, and is very dated.
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, XvID, or even MPEG. Because a DV is not a standalone format, merely a codec-based format, it must be put (wrapped) inside of a container file (wrapper). The container used for DV is AVI in Windows, or Quicktime on Mac. But an AVI is not a DV.
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 DVD-Video is a playback format. A DVD-Video uses MPEG files and audio files muxed into VOB files with IFO and BUP navigation. DV is not at all related to a DVD, aside from sharing a couple of letters from the alphabet.
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 have (in the past) been guilty of suggesting a DV box is a TBC replacement, which is so wrong it’s laughable. It’s akin to saying a potato is a replacement for a computer … makes no sense whatsoever.
The DV Video Format – Not the Best, Not the Worst
While the article has been criticized for being “too harsh” by some videographers, it’s written in reaction to a lot of incorrect information propagated by laymen and novices, which in turns poorly informs others that are new to DV video. It has to stop somewhere. Simply put, keep these things in mind when considering a DV based video workflow, or when using your current DV workflow. DV was created as a balance between compression and quality, and as such, as weakness in both areas that tends to get lost in discussions online (i.e., the idea that DV is the “best” format to use).