What is Audiovisual Input devices? Today, many new PCs are equipped with complete multimedia capabilities. New computers have features that enable them to record audio and video input and play it back. Some of the Audiovisual input devices are discussed below;-
AUDIOVISUAL INPUT DEVICES
The following are the various Audiovisual Input devices;-
Now that sound capabilities are standard in computers, microphones are becoming increasingly important as input devices to record speech. Spoken input is employed typically in transmission, particularly once the presentation will have the benefit of narration. Most PCs currently have phone-dialing capabilities. If you’ve got a electro-acoustic transducer associate degreed speakers (or a telephone receiver electro-acoustic transducer with an earphone), you’ll use your computer to create telephone calls.
Microphones also make the PC useful for audio and video conferencing over the Internet. For this type of sound input, you need a the microphone and a sound card. A cards is a special device inside the computer, which translates analog audio signals (that is, sound waves) from the microphone into digital codes the computer can store and process. This process is called digitizing. Sound cards also can translate digital sounds back into analog signals that can then be sent to the speakers. Using simple audio recording software that is built into your computer’s operating system, you can use a microphone to record your voice and create files on disk., You can embed these files in documents, use them in Web pages, or email them to other people .
There is also a demand for translating spoken words into text, much as there is a demand for translating handwriting into text. Translating voice to text is a capability known as speech recognition (or u)ice recognition). With it, you can dictate to the computer instead of typing, and you can control the computer with simple commands, such as Open or Cancel. Speech-recognition software takes the smallest individual sounds in a language, called phonemes, and translates them into text or commands. Although the Eng lish language uses only about 40 phonemes, reliable translation is difficult. For example, some words in English have the same sound but have different meanings (two versus too, for example). The challenge for speech-recognition software is to deduce a sound’s meaning correctly from its context and to distinguish meaningful sounds from background noise.
Speech-recognition software has been used in commercial applications for years, but traditionally it has been extremely costly, as well as difficult to develop and use. Low-cost commercial versions of speech-recognition software are now available, and they promise to be a real benefit to users who cannot type or have difficulty using a keyboard. Newer-generation speech-recognition programs are much more reliable than the packages that were available a few years ago. Some packages can recognize accurately 80 to 90 percent of spoken words by using large stored vocabularies, or words they can recognize. The user may need to “train” the software to recognize speech patterns or the pronunciation of some words, but this procedure is relatively simple . Another enhancement to speech-recognition programs is their ability tc recognize continuous speech. Older systems required the user to pause between words, which improved accuracy but greatly slowed the data-entry process. Speech-recognition Programs usually require the of a noise-canceling microphone (a microphone that filters out background nose). Most commercial packages come with a microphone.
OTHER TYPES OF AUDIO INPUT
Computers can accept many kinds of audio input. If your computer has a sound card with the appropriate plugs, you may be able to input music from a compact disc, a tape player, a radio, or even a record player. If the audio source outputs sounds in the form of analog waves (as is the case when you speak into a microphone), the computer’s sound card must convert the analog signals into digital code so the computer can store and use it. This is not necessary when recording audio from a compact disc or a digital Video disc, but conversion is required for analog sources such as phonograph records and cassette tapes. If your sound card has a built-in Musical Instrument Digital Interface (MIDI) port, or if you have a dedicated MIDI adapter, you can connect many kinds of electronic musical instruments to your computer. MIDI-based instruments can communicate with and control one another, and any PC can be used to control MIDI instruments and to record their output .MIDI is extremely popular among musicians of all stripes, who use if to its write, record, and edit music, and even to control instruments and effects during performances.
With the growth of multimedia and the Internet, computer users are adding Video input capabilities to their systems in great numbers. Applications such as videos conferencing enable people to use full-motion video images, which are captured by PC video camera and transmit them to a limited number of recipients on a network or to the world on the Internet. Videos are commonly used in presentations on Web pages where the viewer can start, stop, and control various aspects of the playback. The video cameras used with computers digitize images by breaking them into indie visual pixels. (A pixel is one or more dots that express a portion of an image.) Each pixel’s color and other characteristics are stored as digital code. This code is then come pressed (video images can be very large) so that it can be stored on disk or transmitted over a network.
A popular and inexpensive type of PC video camera—-called a Webcam)—can on top of a PC monitor or be placed on a stand, so the user can “capture” images of himself or herself while working at the computer. This arrangement is handy for videoconferencing, where multiple users see and talk to one another in real time over a network or Internet connection . The user also can connect other video devices, such as VCRs and camcorders, to the PC. This enables the user to transfer images from the video equipment to the PC, and vice versa. Affordable video capture cards enable home users to edit their videotapes like professionals.
Digital cameras work much like PC video cameras, except that digital are portable, handheld devices that capture still images. Whereas normal, film cameras capture images on a specially coated film, digital cameras capture images electronically. The digital camera digitizes the image, compresses it, and stores it on a special memory card. The user can then copy the information to a PC, where the image can be edited, copied, printed, embedded in a document, or transmitted to another user.
Digital cameras have become standard equipment for designer of all kind . In the field of Web page design, for example, digital cameras enable a subject and quickly load the images onto their computer. This process saves step of acquiring existing photographs or developing and based photos-—which must be scanned into the computer. Designers can update a Web Site’s illustrations quickly and regularly using digital cameras. Graphic designers can edit and enhance digital ways, using photo-editing software. For example, a landscape designer can use a digital camera to take a picture of a and design software to modify the image to show bow the different landscaping.