Chapter 36 -- Using the Multimedia Accessories

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Chapter 36

Sound and video can greatly enhance your computing experience. Some programs use multimedia to demonstrate concepts that aren't easily explained by using words alone. Others use multimedia to provide realistic simulations of faraway places. And multimedia has more mundane uses too. You can have your computer chirp to let you know that a new e-mail message has arrived, or you can watch full-length movies on your computer screen, for starters.

Most recent computers include at least the basic equipment necessary to take advantage of the multimedia capabilities in Microsoft Windows 2000. With the cost of multimedia hard- ware plummeting, it makes sense for most people to explore what multimedia can do for them.

Here are some things you can do with the multimedia tools provided by Windows:

• Add sounds to documents. For example, you can record spoken instructions for the users of a spreadsheet or a word processing document.
• Play DVD movies, games, or reference works on your DVD drive.
• Play audio CDs on your computer. You can certainly be more productive while listening to Beethoven or Pearl Jam. (Or, at any rate, you can have a better time.)
• Attach custom sounds to various Windows events.
• See an electronic encyclopedia come to life with movies of Neil Armstrong stepping onto the moon or Martin Luther King giving his "I Have a Dream" speech. Or watch an animation of the workings of a CD player.
• Play interactive multimedia games with lifelike sound, video, and animation.

Multimedia Sound

When it comes to multimedia sound, there are two main varieties: wave (.wav) and MIDI (.mid) files. The primary advantage of wave files is that they can be faithfully reproduced on any multimedia computer system. Like an audio CD, a wave file is a recording of the sound. Of course the quality of the playback depends on the quality of the equipment, but a voice sounds pretty much like a voice and a piano like a piano, regardless of the equipment.

MIDI files are more like sheet music. Sheet music describes how the music should be played and which instruments should play which parts. If you give a piece of sheet music to two bands or orchestras, you'll get two different renditions. Because MIDI files only describe the music, they can be stored in a small fraction of the size of wave files. For this reason, many multimedia programs provide sounds in the MIDI format.

Fortunately, Windows supports the General MIDI standard that at least ensures that the correct instruments are used for playback of each part of the sound file. However, there is no guarantee that a voice or a piano will sound anything like a voice or a piano. That is determined by the MIDI capabilities on your computer's sound card.

MIDI files can be translated into real sounds by simulating the sounds with a process called FM (frequency modulation) synthesis, or by using samples of actual instruments (wave table synthesis).

FM synthesis produces sounds that are, at best, low-quality facsimiles of what the creators of the sounds intended. The route to realistic MIDI sounds is a sound card (or an add-on card) with wave-table synthesis, which uses samples of actual musical instruments to play sounds. The results are much closer to recordings of real music and can greatly enhance the listening experience.