Capturing Video in Windows Movie Maker From Digital Sources
Published: February 18, 2002
By Galan Bridgman, Windows XP Expert Zone Community Columnist
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The best way to capture high-quality digital video is using a digital video capture card such as IEEE 1394, also known as firewire, or on Sony systems, i.Link.
I've been quite happy with the results of the analog video capture card that I discussed in my last column. However, the perfectionist in me cringes when I think of what the video goes through before it's finally digitized and stored on the computer's hard drive. When you have a digital video camera, you lose a significant amount of quality if you don't use a digital video capture card to transfer it to your computer.
For professional video work, I use a digital video card from Canopus. But the total cost of this system is prohibitive for home video editing. But many high-quality digital video cards are affordable for the average home user.
IEEE 1394, Firewire, iLink
For example, my consumer grade Sony camcorder records video in digital format on tape and it has i.Link (IEEE 1394) output. This type of output offers a high data transfer rate — up to 400Mbps — which is necessary to transfer the large volume of data required for full-motion video. All you need for Windows XP to capture this digital video directly from the camera is an OHCI-compliant IEEE 1394 port. Many newer computers have these ports built in. If yours doesn't, several companies offer 1394 cards for well under $100. These are easy to install if you have an open slot in your desktop computer. There are also 1394 cards available for laptops.
Just make sure of the OCHI compliancy before purchasing. OHCI stands for Open Host Controller Interface, and is an industry standard for IEEE 1394 interfaces. Microsoft worked very hard during Windows XP's development to make sure that both Windows XP and a majority of the available 1394 products were OHCI-compliant. This helps ensure a great user experience.
Recently, I bought a Western Digital IEEE 1394 card shown in Figure 1 below. The box stated it was OHCI-compliant, and I noticed the card had an NEC 1394 chip on it, which Windows XP supports. I simply plugged the card in, turned on the computer, and Windows XP recognized it and installed all necessary drivers without my having to make a single click.
Figure 1
The same thing happened when I plugged in my Sony camcorder to the 1394 port for the first time. Windows XP presented a dialog box, which asked what I wanted to do with my new camera. I clicked Record in Movie Maker, and Movie Maker opened with its Record dialog open and my video showing in its preview window.
Before you start capturing video, make sure you have plenty of hard disk space. Your final product may not require a lot. But, the temporary files Movie Maker uses to store your raw video before compression can be quite large. You also need a fairly fast machine because of the volume of data to be processed. Machines of 1GHz or above are probably fine for most video tasks you'll want to perform.
To get started capturing video
1. | Open Movie Maker (Click Start, click All Programs, click Accessories, and then click Windows Movie Maker.) |
2. | Click Record. The Record window opens with a preview of your video, along with options for your source device, encoding quality, and target platforms. You'll also notice that, if you are using an IEEE 1394 devices, a set of controls appears at the bottom of the window for controlling your device as shown in Figure 2 below. These buttons control your camera so your hand never has to leave your mouse. Alternatively, you can use the buttons on your camcorder to start and stop the playback.  Figure 2 |
3. | Clear the Record time limit and Create clips check boxes if you don't wish to take advantage of those features. |
4. | Also, you might want to check the Disable preview while capturing box . This can improve performance since displaying the video takes up some CPU power. |
The Setting quality is important. You can choose Low quality, Medium quality, High quality or Other. Click on each setting and read the text below it that describes the bitrate, size, and frame rate of the final video.
Clicking Other lets you choose from a wide variety of encoding profiles to better suit your desired target. For example, you can select options that are well-suited for playback on a Pocket PC, for low-bandwidth streaming over a modem, or for very high bitrates for archival quality and playback from CDs or hard disks. Experiment with these settings until you become familiar with the tradeoffs between quality and bitrate and find the right selection for your desired result.
After you experiment with quality settings, you can begin capturing video, whether it's prerecorded, or live, and use Movie Maker to edit it and produce the final movie.
Live Capture and Streaming
My last column mentioned how I was using the analog capture solution to stream live video. I have been curious how streaming would work with digital video capture. I discovered that it indeed works, but because the volume of data being transferred is higher and the compression is performed in real time, I recommend you have a CPU of at least 1.4 GHz. My 933MHz Pentium III system that normally runs at about 52% CPU utilization with the analog capture solution was running at over 90% with digital capture, with frequent peaks of 100% when the video content changed scenes or moved fast. This will cause frames to be dropped, so keep a close eye on that CPU utilization figure displayed by Windows Media Encoder. Choosing a lower frame rate or smaller video size would also help, but that somewhat defeats the purpose of using DV capture to get higher quality.
Galan Bridgman is a developer, architect, and enthusiast for digital media technologies. He co-developed QuickTime for Windows for Apple Computer. At Starlight Networks he developed innovative client and backend technologies using ActiveMovie® and NetShow® Server, the precursors to Windows Media Technology. He is a full-time consultant, and is currently developing a next-generation, fully-automated radio station using Microsoft Windows Media 9 Series technologies. After hours he enjoys showing others how to make the most of Microsoft's latest Windows Media applications. Check Galan's Web site for more information about him.
