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Frame-Grab Tutorial
Written by Jeremy Butler   
Thursday, 02 November 2006
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Frame-Grab Tutorial
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Importing Video
Into Your Computer

What is one to do if your video is not already on a DVD? You have two options then:

  1. Copy your video (from videocassette or wherever) to DVD and then go through the steps above.
    • This is most easily done by connecting a VCR to a DVD recorder, but you may have to cope with "copy protection" (see below).
  2. Transfer your video directly to your computer and then grab a frame.
    • Follow the directions below and you're on your way!

Coping With Copy Protection

As we alluded to above, Congress and the film studios have set up roadblocks for fair-use copying of DVDs and VHS cassettes. Some of the processes outlined below will not work with commercial, recorded DVDs/cassettes because of various "copy protection" devices and schemes. As is explained in this Wikipedia article, copy protection is "any technical measure designed to prevent duplication of information." In our case, that means that importing a movie into a computer may fail because of something encoded onto the DVD/cassette.

The legality of the blocking of fair-use copying of movies -- as well as the legality of hardware/software to get around that blocking -- is hotly contested. For arguments on both sides of the issue, see the Wikipedia article cited above. If you feel comfortable circumventing copy-protection measures, then you should investigate the following hardware, software and online resources:

  • Hardware
    • Sima CT-2 GoDVD! Digital Video Enhancer ($60, as of 6 October 2006; Froogle Search)
  • Software
    • DVDFab Decrypter (Windows) -- as explained on its Website, "It copies entire DVD movies to hard disks, and removes all the protections (CSS, RC, RCE, APS, UOPs and Sony ARccOS) while copying."
  • Online information
    • -- Finnish site offering guides and advice on DVD copying (although in January 2006 it cut back on its guides).
    • -- bills itself as "The definitive DVD backup resource."
    • -- guides/tutorials and software for DVD copying.

The Basics of Video Output

Both DVD players and VCRs send their signals out through connectors resembling those at the left. These RCA-style plugs carry video and audio signals from a DVD player/VCR to a TV set or amplifier.
[Tech note for nerds: composite vs. component connectors.]
Typically, yellow is for video output, red is for the right audio channel and white for the left.

Looking at the back of a DVD player (below) we see a bewildering array of jacks, but if we follow this color coding we'll succeed in making our connections.

In this case, we need only plug into the jacks labeled "video," "R," and "L." We also have the option of using an S-video jack (marked "S") instead of the yellow RCA video connector. S-video is a higher quality video signal.

Most VCRs are simpler than DVD players and have only three output jacks (and no S-video option).

From the Video Player to the Computer

Once one gets the video signal out of a VCR or DVD player by plugging into its RCA jacks, how does one get it into the computer? Essentially, there are three ways to accomplish this task:

  • External capture devices, which connect to the computer through USB or FireWire ports.
  • Internal capture cards with special video inputs.

Let's consider these one at a time...

External Capture Devices

Several "external" products sit beside your computer and happily accept video signals from DVD players, VCRs, and camcorders. Examples range in price from $75 to $300. The products frequently change, but here are a few current examples with links to their manufacturers' Websites:

  • ADS PYRO A /V Link (Windows and Mac)
  • Dazzle Digital Video Creator Platinum and Hollywood DV-Bridge (Windows and Mac)
  • Hauppauge WinTV (Windows)
  • Pinnacle Studio MovieBox (Windows)
  • Belkin USB VideoBus (Mac)
  • ATI
  • Canopus ADVC-110 (Windows and Mac)
  • Miglia Director's Cut (Windows and Mac)
  • Sony DVMC-DA2 (Windows)
  • Also, a digital camcorder with analog inputs can serve this function; but see the important caution below.
    • Sony Digital8 HandyCam (approx. $500)
    • Numerous miniDV camcorders ($250 to infinity)

As is typical with such devices, the ADS PYRO A /V Link has jacks in front for RCA connectors: yellow, red and white for video, left, and right audio channels, respectively. And it patiently sits between the video source and the computer--translating analog video signals into digital ones.

It provides additional options for connections via S-video (which we saw in the back of our DVD player above) or digital video from a DV camcorder.

The ADS PYRO A /V Link connects to the computer via a FireWire cable (below, right), an interface which comes standard on all Macs and many Windows computers. Another, virtually universal connection for video capture devices is through a USB cable (below, left).

FireWire cable connectors

Once you've made this physical connection, each of these devices uses software to facilitate the recording ("capturing") of video.

The advantages of these external devices over internal ones:

  • Easy installation: no opening of the computer to add a new component
  • Mobility: move easily from one computer to another
  • Compatibility with a wide range of computers (some even operate on both Windows and Mac computers)

However, some of the early USB devices suffered from the relatively slow USB connection, which can result in:

  • Lower quality image
  • Smaller image size
    • Be wary of devices that are limited to 320x240 pixel resolution. What you need is 720x480 pixels (sometimes resized to 640x480). Image size is explained further on page five.
  • Slower frames-per-second (fps) rate; some external devices cannot handle video's 30 fps
  • Unreliable video capture (missing frames)

The Need for Speed

The high speed of current USB and FireWire connections prevents the problems noted above with the relatively slow connection of early versions of USB and thus allows:

  • High image quality
  • Maximum image size
  • Full, 30 frames-per-second frame rate
  • Very reliable video capture (few missing frames)

Consequently, today's video-capture devices seldom have problems with slow connections. Still, it's important to make sure that any device you select can capture images at full size (either 720x480 or 640x480 pixels) and can play video at its full speed (30 fps).

Incidentally, FireWire is the most common way video professionals transfer video from cameras to computers. All Macs and many Windows computers have FireWire ports. You can also add FireWire to a computer via an adapter card that costs about $25 and is installed inside the computer.

(Some) Digital Camcorders Do Double Duty

Digital camcorders can sometimes be pressed into service as de facto analog-to-digital converters.

Important note: This only works if a camcorder has an analog video input and a FireWire output.

If your digital camcorder has an analog input you can accomplish an analog-to-digital conversion by:

  1. Re-recording from a DVD player/VCR to the camcorder,
  2. Connecting the camcorder to the computer via FireWire and,
  3. Recording the video on the computer

Of course, this involves the extra step of re-recording your analog material to digital tape, which is time consuming.

However, some digital camcorders (e.g., the Sony DCR-TRV230) allow you to skip this step. Cameras such as this will instantaneously convert an analog signal to digital. You just plug your DVD player/VCR into the camcorder and the camcorder into the computer. This is known as a "pass-through," because the video signal passes through the camcorder to the computer. No re-recording is necessary.

It must be stressed, however, that many digital camcorders--even ones with analog inputs--do not support pass-through conversion. Additionally, many will not record video from copy-protected sources.

Internal Capture Cards

Normally, you cannot simply plug a DVD player or VCR into your computer without an external capture device, but, if you are willing to open it up and install an "internal" component, you can add that capacity to the machine.

Much like the external capture devices above, internal capture cards accept analog connectors such as RCA plugs. But instead of sitting beside your computer, they are installed inside--with access to their inputs usually found at the back of your computer. There are numerous capture cards on the market. We won't discuss them in detail here, but one example is:

If you were to install the WinTV-PVR-350, you'd wind up with the above interface on your Windows-based computer's rear. The connectors are for, from left, FM radio, cable-TV, S-video, an A/V "breakout cable", audio, and an infrared remote control. The breakout cable has several connectors on it--allowing you to send the computer's video out to a television set or other device.

For additional information, please see the extensive tutorial about capture cards available over here (although, since it was published in 2003, it is a bit dated).

One additional option is to modify the connection between your computer and its monitor. Several companies have developed monitor cards (aka, "video cards" or "graphics cards") that can both run your monitor and accept video from your VCR and DVD player.

These double-duty video/graphics cards range in price from $100 to $600 (and above) and include:

  • ATI All-in-Wonder (Windows)
  • Matrox Marvel eTV (Windows)
  • Matrox RTMac (Mac)

If installing a component inside your computer makes you shudder in fright, you're better off with an external capture device. If not, just pop the top on your computer and install your capture card or video card in an appropriate slot. CNET has a step-by-step tutorial, including helpful photos of a a video-card (i.e., AGP) slot and a guy pressing a card into it:

An AGP slot

Inserting a video card into an AGP slot

You'll find capture/monitor cards operate on much the same principle as the external video converters. The main difference is that one connects the cables from the DVD player or VCR to special sockets sticking out of the card--as indicated in this diagram for the Matrox eTV card. (Note the connectors for red, white, and yellow RCA plugs.)

Similar to the external devices above, capture/monitor cards provide software for capturing still and motion video. In contrast to the external devices, however, capture/monitor card connections do not have to go through an external interface and thus the video flow is considerably faster and more reliable.

And, as you've probably guessed already, faster video flow means:

  • Higher quality image
  • Larger image size
  • Faster frame rate (fps)
  • More reliable video capture (fewer missing frames)

Now That You've Selected a Device . . .

Once you've selected a device for getting your analog video into your computer, you must use software for the actual capturing. Although each video application does this a bit differently, there are general principles about image size and format that are helpful to know.

We address these issues on pages four and five.

Last Updated ( Monday, 24 September 2007 )
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