Multimedia Devices

Multimedia devices allow computers to present information in methods previously not associated with computers. Multimedia devices allow the integration of video and sound in presentations, greatly increasing their breadth and impact. Multimedia packages generally include a CD-ROM, a sound card, and various software.

CD-ROM (Compact Disc Read-Only Memory) discs are capable of storing 650 MB of information. Since sound, graphics, and video can take up a great deal of space, CD-ROMs are vital to multimedia presentation. CD-ROMs are rated according to their speed. The standard is double-speed, which reads data at twice the rate of a normal music CD player. Triple, quad, and 6-speed CD-ROMs are available as well.

Sound cards, which allow recorded and synthesized sound to be played by the computer, are often referred to as being "8-bit" or "16-bit." Sound, which is analog, must be converted to digital data to be used by a computer. This is accomplished by recording the location of a sound wave at certain time intervals. 8-bit sound cards are capable of recording sound at 22.1 kHz, or 22,100 samples per second. 16-bit cards are capable of 44.2 kHz sampling, the sampling rate of music CDs.

Video, since it is a series of images, takes up an incredible amount of space. Computers are not capable of presenting full-screen digital images at the speed necessary for video. Therefore, this video must be compressed in order for the computer to display it. The standard for video compression is MPEG, and MPEG devices are available which allow computers to fully utilize MPEG-compressed video.