A webcam is a simple digital camera capable of taking video or still images for transmission over the Internet. Unlike digital cameras (next section), webcams don't include storage capabilities. Most webcams plug into a USB port, but a few have used IEEE 1394 or parallel ports.
Webcams are generally used in live chat situations, such as with AOL Instant Messenger or other IM clients. They offer resolutions ranging from sub-VGA to as high as 2 million pixels (2 megapixels). Some offer autofocus and zoom features for better image clarity, and some have built-in microphones.
Digital Camera
Digital cameras have largely replaced film cameras for both amateur and professional photography. They use CMOS or CCD image sensors to record images onto internal or card-based flash memory form factors such as Compact Flash, SD, Memory Stick, xD-Picture Card, and Smart Media.
MIDI Music and MIDI Ports
M usical instrument digital interface (MIDI) music is created from digitized samples of musical instruments that are stored in the ROM or RAM of a MIDI device (such as a sound card) and played under the command of a MIDI sequencer. MIDI sequences can be stored as files for future playback, and can be transferred between sound cards and MIDI-enabled devices such as keyboards via the MIDI port. To learn more about MIDI ports, see the section "MIDI Port," earlier in this chapter.
Sound Card
Sound cards are used to record and play back analog audio, and most can also play back digital audio sources as well. When recording analog audio sources such as CDs, line in or microphone in, sound cards digitize the audio at varying sample rates and store files in either uncompressed forms such as WAV or compressed forms such as WMA or MP3.
Most recent sound cards support 5.1 or 7.1 surround audio, and many sound cards also support digital stereo or surround audio playback standards via SPDIF ports. In recent years, sound cards have become less popular due to the popularity of onboard audio, but sound cards are preferred by users who create audio recordings.
