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Jan's Computer Basics:

Input: Multimedia

multimedia	gifMultimedia is a combination of sound and images with text and graphics. This would include movies, animations, music, people talking, sound effects like the roar of a crowd and smashing glass.



Sound Input

MicrophoneHeadset with microphoneElectric keyboard


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Recording sounds for your computer requires special equipment. Microphones can capture sounds from the air which is good for sound effects or voices. For music the best results come from using a musical instrument that is connected directly to the computer. Software can combine music recorded at different times. You could be a music group all by yourself - singing and playing all the parts!

Voice Input

LipsVoice input systems are now available at the local retail level plus being built into mobile devices like phones and tablets. If you have a choice of programs, you must be careful to get the right system or you'll be very disappointed.

Decide first what you want to do since a voice input program may not do all of these:

Data entry  - Talking data into the computer when your hands and eyes are busy should certainly be more efficient. You'd have to be very careful about your pronunciation!
Command and control - Telling the computer what to do instead of typing commands, like saying "Save file". Be careful here, too. The dictionary of understood words does not include some of the more "forceful" ones.
Speaker recognition - Security measures can require you to speak a special phrase. The computer must recognize your voice to let you in.
Speech to text - Translating spoken words direct to type would suit some authors just fine. You'd have to watch out for those "difficult to translate" phrases like "hmmm" and "ah, well, ... ummm."

A number of companies are now using speech recognition in their telephone systems. For example to find out what your bank account balance is, instead of punching in your account number on the phone keypad and choosing option 3 for current balance, you could speak your account number and say "Current balance". The computer will even talk back and tell you what it thinks you said so you can make corrections. Wow!

How do they change voice to data??
computer print out coming out of mouth
1. Convert voice sound waves to digital form (digital signal processing -DSP)
2. Compare digitized voice input to stored templates
3. Check grammar rules to figure out words
4. Present unrecognized words for user to identify

Types of Voice Recognition Systems

Speaker dependent system The software must be trained to recognize each word by each individual user. This might take hours of talking the dictionary into the computer, to be optimistic.
Speaker independent system The software recognizes words from most speakers with no training. It uses templates. A strong accent would defeat the system, however.
Discrete speech recognition The speaker must pause between words for the computer to tell when a word stops.
Continuous speech recognition The speaker may use normal conversational flow.
Natural language The speaker could say to the computer "How soon can we ship a dozen of product #25 in blue to Nashville?" - and get an answer!!
Science fiction has come to life!!!

Video Input

Digital CameraA digital camera takes still photos but records the pictures on memory cards. The information contained can be uploaded to a computer for viewing. Many cell phones include a camera. Some have two, one to take a picture of your face and one to show what you are looking at.

CamcorderA camcorder records moving pictures that can be uploaded to the computer.

Both of these video formats take huge amounts of storage.

Web CamA web cam is a tiny video camera designed especially to sit on your computer. Some laptops have one built into the case. It feeds pictures directly to the computer. Of course you are limited by the length of the cable that connects the camera to the computer. But like any camera, it will take a picture of what you point it at!

So what do people do with a web cam? They use it for video conferencing over the Internet or Skype video phone calls. They show the world what's going on outside their window (weather, traffic). They take digital pictures and make movies of family, pets, snow storms, birthday parties, whatever.

Tablet showing streaming tv show Streaming video, movies, and television can now play on your desktop and mobile devices using Internet services like YouTube or using apps from subscription services, like DirecTV or NetFlix.


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