UNIT 6

Multimedia Devices

6.1 Output devices

Multimedia is a mixture of different media -- such as text, video, audio, graphics and data -- that work together to provide you with all of the computing functions you need. To use multimedia, input and output devices are responsible for both transmitting and receiving information.

6.2 CD-ROM

• It stands for Compact Disc Read-Only Memory.
• It is an optical disc that contains audio or software data whose memory is read-only.
• A CD-ROM Drive or optical drive is used to read them.
• They have speeds ranging from 1x to 72x, meaning it reads the CD roughly 72 times faster than the 1x version.
• These drives are capable of playing audio CDs and reading data CDs, including CD-R and CD-RW discs.

6.3 DVD

• It stands for "Digital Versatile Disc."
• It is a type of optical media used for storing digital data.
• It has the same size as a CD, but has a larger storage capacity.
• Some DVDs can be formatted for video playback, while others may contain various types of data, such as software programs, computer files etc.
• A standard video DVD can store 4.7 GB of data, which is enough to hold over 2 hours of video in 720p resolution, using MPEG-2 compression.
• They are also used to distribute software programs.
• Since some applications and other software are too large to fit on a single 700 MB CD, hence DVDs provide a way to distribute large programs on a single disc.
• Writable DVDs can store a large number of files and back up data.
• They include DVD-R, DVD+R, DVD-RW, DVD+RW, and DVD-RAM.

6.4 Scanner

• When referring to hardware, a scanner or optical scanner is a hardware input device that optically "reads" and converts it into a digital signal.
• For example, It is used to convert a printed picture, drawing, or document into a digital file which can be edited on a computer.
• Hence, a scanner is a digitizer, which is a type of input device.
• It takes information from the real world and converts it into digital information for a computer to store or manipulate.
• It is only able to send information to the computer and cannot receive information from the computer like a printer.
• When referring to software, it is a program that scans computer files for errors or other problems.
• An example is an antivirus program, which scans the files on the computer for viruses or other malware.

Connections:

• Firewire
• Parallel
• SCSI
• USB

Types:

• Sheetfed scanner 
• Image scanner
• Text scanner
• Handheld scanner 
• Card scanner 

6.5 CCD

• It stands for "Charged Coupled Device."
• They are sensors used in digital cameras and video cameras to record still and moving images.
• It captures light and converts it to digital data that is recorded by the camera. And is often considered the digital version of film.
• The quality of an image captured depends on the resolution of the sensor.
• In digital cameras, the resolution is measured in Megapixels.
• The result is a larger photo with more detail.
• CCDs in video cameras are usually measured by physical size.
• The larger the sensor, the more light it can capture, hence it will produce better video in low light settings.

References:

1. Multimedia : Computing, Communications & Applications by Ralf Steinmetz and Klara Nahrstedt, Pearson Ed.

2.            Multimedia Systems Design by Prabhat K. Andleigh & Kiran Thakrar, PHI.

3.            Principles of Multimedia by Parekh, TMH.