Video capture cards

If you have no way to utilize FireWire, you have to use a video capture card to convert the analog video signal into digital information. Video capture cards, like cameras, are available at a wide range of price points. The more you spend, the higher quality your video capture will be.

Video capture card settings
Using a video capture card involves connecting your camera to the capture card and then specifying the settings for your capture. Where and what settings you can specify depends on your capture card and your video-editing platform. Essentially, you specify the following:

Resolution: The dimensions of your screen capture

Frame rate: How many frames per second to capture

Data rate (or compression): Whether to capture the video uncompressed or use a codec during capture

You also may be able to adjust the video settings for your capture, such as brightness, contrast, and saturation. However, the adjustments offered by most budget capture cards tend to be fairly coarse. A better approach is to digitize your video as purely as possible and to do your adjustments using video-editing software, which enables a much finer degree of control — and the ability to "undo."

To capture the highest quality video possible, try to capture full screen, full frame rate, and uncompressed. You may have to scale back, however, depending on your hardware situation. Full-screen uncompressed capture is a very data intensive process, requiring a fast machine and lots of storage. If you have to scale back, start by trying to use a different encoding scheme such as YUV. If your machine still can't capture full frames reliably, you'll have to reduce your resolution, possibly to 1/2 size (320×240). This is a perfectly acceptable starting point for a video podcast, provided you can capture at full frame rate.

Digitizing via a capture card using SwiftCap: A step-by-step example
If you are capturing video via a capture card, you can choose some settings. Most video-editing platforms come with a video capture application that allows you to access your video capture card and adjust your settings. In this example, we'll use SwiftCap, which is the video capture application that comes with all cards sold by Viewcast, one of the more popular video capture card manufacturers. It has some nifty features that you'll find handy for successful video captures.

Follow these steps to digitize video with SwiftCap:

1. Make sure that your capture card is installed correctly and that your camera or videotape deck is connected to your capture card.

2. Open SwiftCap. Provided your camera is running, you should see a preview of your video (see Figure 1). If you don't see a video preview, make sure "Preview Video" is checked on the View menu.


Figure 2: The ViewCast SwiftCap application

3. If you're still not seeing video, make sure your video source is correct. Many video capture cards have multiple inputs, for example, a composite input and an S-Video input. To check your source setting, choose "Capture Settings" from the Settings menu or click the capture settings icon (see Figure 2).

4. Select the appropriate source from the drop-down Source menu on the left side of the Capture Settings window (see Figure 3).


Figure 3: Select the appropriate source in the Capture Settings window to make the preview active.

5. Before you do any capturing, make sure your system is capable of capturing the screen resolution and encoding scheme you want to use. Ideally, you want to capture full screen (720×486, or 640×480 if your capture card automatically scales the input), but this requires a fast computer and plenty of storage. SwiftCap includes a handy disk performance analyzer that can save you lots of woe. From the Tools menu, choose "Disk Performance." This brings up the Disk Analyzer shown in Figure 4.


Figure 4: Click "Profile Drive" in the Disk Analyzer window to analyze your hard drive performance.

6. Select the drive you intend to capture to in the Local Drives pane, and click the "Profile Drive" button. The analyzer then determines the speed at which you can capture video and displays the results in the lower right. You can see in Figure 4 that this drive is capable of capturing only 20.8 frames per second using RGB 32 encoding. We'll have to choose a different encoding scheme to get the full frame rate.

Tip You should always capture video to a drive other than the system drive if possible.

7. The idea is that you have to get your frame rate comfortably over 30 frames per second. YUV encoding is more efficient, so you can usually get your frame rate up considerably by switching to a YUV encoding scheme. In Figure 5, you can see that switching to YUY2 puts our potential frame rate over 40, which is far more than we need.


Figure 5: Using a YUV encoding scheme is more efficient and allows higher frame rate captures.

8. After you've found settings that work with your system, go back to the Capture Settings window and enter those settings (see Figure 6).


Figure 6: Be sure to choose the right settings in the Capture Settings window.

9. Next, specify which drive you want the captured file saved to. Select "Capture Destination" from the Settings menu, or click the capture settings icon to bring up the Capture Destination window (see Figure 7). Clicking the double arrow button at the top right opens a browse window where you can specify a location and a filename. Be sure to use the same drive that you tested in Step 5.


Figure 7: Specify where to put your captured video file.

10. You should now be ready to capture video. Rewind the tape to just before where you want to start capturing, start tape playback, and then start the capture process by selecting "Start" from the Capture menu or by clicking the start capture icon.

11. SwiftCap disables the video preview during capture, so you have to either monitor via your camera's monitor or an external monitor. When you've captured what you needed, choose "Stop" from the capture menu or click the stop capture icon.

12. After you stop your capture, SwiftCap displays a capture results window. It is critical that your capture have zero dropped frames. If your capture dropped frames, you should recapture your video using a different encoding scheme or a smaller capture resolution.

That should be it. Using a capture card requires a few more steps than using a FireWire setup, but you should be able to get equally good quality, provided you're using a good quality capture card.