Chapter 20: Working with Video

How Does Windows Work with Video Data?

You can use various video capture devices, such as digital video cameras, to get video information into your computer. See Chapter 13 for instructions on how to install video capture devices. To display video, Windows uses your screen, and to play the accompanying audio it uses your sound board and speakers.

Because the amount of data coming from a digital video camera is so immense, your computer can't process and store it fast enough. Instead, video data is compressed on its way into the computer from the camera and is then stored in a compressed format. A very fast DSP (digital signal processor, a kind of specialized computer) chip in your video capture hardware does the actual compression. Windows comes with a number of codecs, programs for video compression and decompression, so that it can decompress and recompress video data when you want to display or edit it. Windows also includes DirectX, a feature that enhances video playback. Windows stores most video in AVI files, files with the filename extension .avi. Other popular formats for video files are QuickTime (.qt) and MPEG (.mpg).

To see a list of your installed video capture devices, along with a list of the available codecs, choose Start | Control Panel; click Sound, Speech, And Audio Devices; click Sounds And Audio Devices; and click the Hardware tab. You see the list of audio and video devices your computer can use (see Figure 19-4 in the previous chapter). To see a list of video capture devices, click the Legacy Video Capture Devices entry, click the Properties button, and click the Properties tab. To see a list of codecs that are available, click the Video Codecs list item, click the Properties button, and select the Properties tab.