Standard File Formats for Graphics Files

This image is saves as JPEG and is 13.8 KBImage

This image is saved as GIF and is 20.5 KB Image

This image is saved as PNG and is 81.3 KB Image

There is not much difference between the three images, all three become pixelated when zoomed in. However, the GIF file becomes more pixelated than the others as it uses lossless compression to reduce the file size.

JPEG uses lossy compression and is an image file format supported by the web. The information that is deleted through the compression technique is data that the human eye cannot see. GIF uses lossless compression but only supports 256 colours, and is better to be used for images with few colours (black/white) and small text. A lossless PNG file can be 5% – 25% more compressed than a GIF file of the same image. Saving, restoring and re-saving a PNG image will not degrade its quality also PNG does not support animation like GIF does.

Implications of Multimedia Technology

Wireless Communications – Wi-Fi vs Bluetooth

Bluetooth is a wireless technology standard for exchanging data across short distances. The devices used by Bluetooth are telephones, tablets, media players. Wi-Fi allows an electronic device to exchange data wirelessly over a computer network.

 

Bus Communications – Firewire vs USB

Firewire is a very fast external bus that supports data transfer rates of up to 400 Mbps.  Products supporting the 1394 standard go under different names, depending on the company. Apple, which originally developed the technology, uses the trademarked name Firewire. USB is short for Universal Serial Bus, an external bus standard that supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems and keyboard.

 

Magnetic Storage

2 terrabyte hard disk drive might be found inside a new PC. External hard disk drives offer around 1 terrabyte.

 

Optical Storage

CDs and DVDs have been a common means of storing multimedia data. Around 2 hours of video can be stored on a DVD. The amount of video can be stored on a Blu-Ray DVD depends on the bit rate but is around 9 hours.

 

Online Storage

Cloud storage is a model of networked online storage where data is stored on multiple virtual servers, generally hosted by third parties. Companies need only pay for the storage they actually use. Storing extremely large volumes of information on a local area network (LAN) is expensive. It doesn’t require installation, doesn’t need replacing, has backup and recovery systems, has no physical presence, requires no environmental conditions, requires no personnel and doesn’t require energy for power or cooling. However has several major drawbacks, including performance, availability, incompatible interfaces and lack of standards.

 

Processing

The processor has to manage the main tasks involved in any multimedia development, therefore the faster a processor the better.

 

Display

The type of output device used can have an impact on multimedia. Virtual 3D provides a separate image for each eye, generally requires 3D glasses where as Real 3D – projects a moving image into space

 

The Impact of the Internet on Family and Employment

There are many implications that the internet has on families. It makes it much easier for families all around the world to stay in touch. They can do this through instant messaging or email. They can also stay in touch through social networking sites such as Facebook. Video conferencing also makes it much easier for families to stay in touch as they can have video calls and actually see each other using applications such as Skype. The internet has made it much easier for people to send one another digital photos and videos, they can do this through social networking sites or email. The increase in people with mobile devices in huge, this means it is very easy for everybody to be connected. The internet has also had an impact on employment. Employees will have instant access to a wide range of information they may need to complete their work. E-commerce has had a big impact in that people can now buy/sell goods online. This means people don’t have to leave their workplace/home and it is available 24/7. Email in the workplace keeps employees connected and also means that messages are stored and a record is kept. Video conferencing is also useful in the workplace in that employees do not have to leave their desk to attend meetings as they can be held through video conferencing. 

Vector Graphics

Vector graphics are created on the computer rather than sampled like bitmapped graphics and can be resized and stretched. Vector graphics look better on devices with a high resolution, where as bitmapped graphics look the same regardless. Vector graphics take up less memory space than bitmapped graphics however, only the individual shapes can be edited unlike bitmapped graphics where each individual pixel can be edited. Vector graphics store different properties about the image such as shape, fill colour, position, line width and line colour. Draw programs are used to create vector graphics such as inkscape and serif.

Audio-Editing Functions

Stereo – sound that is directed through two or more speakers so that it seems to surround the listener and to come from more than one source

Surround Sound – a system of stereophonic sound involving three or more speakers surrounding the listener so as to create a more realistic effect

Fade – A gradual increase or decrease in the audibility of a sound

Audio File Types

MP3 – A means of compressing a sound sequence into a very small file, used as a way of downloading audio files from the Internet.

WAV – Short for Waveform Audio File Format, (also named, Audio for Windows) is a Microsoft and IBM audio file format.

Network Strategy

A network is two or more computers linked together, it is used to share information across an organisation. 

Types of Network

LocaL Area Network (LAN), Wide Area Network (WAN), Metropolitan Area Network (MAN) and Home Area Network (HAN).

Topologies 

A network topology is used to describe the layout of a computer network. Each has its own characteristics.

A Bus Topology has a start and end point. Data packets are sent out along the bus with the address of the receiver. All of the nodes on the network read every message to find out if they are the intended recipient.

A Ring Topology involves all computers being connected to form a ring. Packets are passed from the sender through each computer until it reaches the recipient. 

A Star Topology involves all nodes being connected to a central node. Messages are passed to the central node and then to the recipient. If the central node (a hub, switch or router) is broken, the network cannot function.

A Mesh Topology means that each node must be connected to at least 2 other nodes. If one link is broken, packets can still reach where they need to go, through a different link.

A Fully Meshed Topology means that every node must be connected to every other node. If one link is broken, packets can still reach where they need to go, through a different link.

A Tree Topology is a number of star networks linked together. The internet uses a tree topology.

Functions of an OIS

Gathering Data

The first function of an OIS is to gather the data. 

 

Storing Data

Information in an organisational system is stored in one of the following ways.. Hard Disk Drive, CD-ROM, DVD, Tape or Memory Stick

 

Processing Information

Processing can be applied to data to turn it in to information through searching/selection, sorting/rearranging, aggregating or performing calculations.

 

Outputting Information

This can be printing records from a database.

Data Representation

Positive Integers, Negative Integers and Real Numbers.

A computer represents positive integers using The Binary Number System. It uses the numbers 1 and 0 to represent numbers in the computer. It is simple in which it only has to generate and detect 2 voltage levels, it also means that calculations are kept simple. There are only 4 rules for addition/subtraction/division/multiplication. Example: the number 200 can be represented as 11001000. There is a simple way of representing a negative number in binary. The first bit of the number to represent whether the number is positive or negative. This is called Signed Bit representation. Example: 011 = 3 111 = -3. This is a problem as it means there are 2 values for zero (000 = 0 and 100 = -0) However, we can use Two’s Complement to represent negative numbers. We do this by changing all the 1’s to 0 and all the 0’s to 1, we then add 1. Example: 5 = 00000101, change all the 1’s to 0 and 0’s to 1 = 11111010 and then add 1 = 11111011. The range of integers which can be stored in two bytes is -32768 to 32767. This is still a problem due to the increased memory needed to store the large number of bits needed.. And so we use Floating Point Notation. The real number is stored as 2 separate bits of data. The mantissa holds the number without the point and the exponent holds the number of places that the point must be moved in the original number to place it at the left hand side. If the size of the mantissa is increased then the accuracy of the number held is increased and if the size of the exponent is increased then the range of the numbers which can be stored is increased.

Text

A list of all characters a computer can process and control is called the character set and each character is represented by a unique binary code. The internationally agreed code used to represent American English is the American Standard Code for Information Interchange (ASCII). It used 7 bits to represent each character from 0000000 to 1111111. This can be used to store 128 characters. Extended ASCII was then created and uses 8 bits to represent each character from 00000000 to 11111111. This can be used to store 256 characters. This is a problem as it was based on European alphabets and don’t contain other characters such as Arabic or Japanese characters. The solution to this is Unicode. It uses 16 bits to represent each character which can be used to store 65,536 characters.

ASCII Table:

Bitmapped Graphics

An image is made up of pixels, which are tiny dots. The resolution determines the quality of the picture. A high resolution image will have more pixels than a low resolution image. The image is saved in a two dimensional array using binary numbers to represent the colours in the pixels. An image with 2 colours means each pixel is represented using one bit. An image with 4 colours means each pixel is represented using 2 bits. The number of bits used to represent the colour of the pixels is called the bit depth. To store an image which is 5×7 inches at 600 dpi using 65,536 colours, 24.03 mb of memory would be required. This is because we times the size of the image by the dpi.. (5×600)x(7×600) = 12600000. We then times this by 2 bytes.. 12600000 x 2 = 25200000 bytes. We then have to divide this by 1024 to get it into Kilobytes.. 25200000/1024 and then by 1024 again to get it into megabytes.. = 24.03 mb. In a bitmapped graphic the file area is fixed. The graphic can also be edited to pixel level. However, enlarging the image causes a loss in quality, the file size is very large and the file is printed at the same resolution as it is shown on the screen.

Bitmapped Graphic:

Standard Algorithms

Linear Search

A linear search is a search through a list, comparing each item with the search criteria. It returns the position of the item or displays a message to say it cannot be found.

Algorithm:

Get search_item

 

REPEAT for all items in list

IF current_item = search_item THEN

position = current_item_position

EXIT LOOP

END IF

END REPEAT

 

Display position

 

Count Occurrences 

Counts the amount of times an item appears in the list

Algorithm:

Get search_item

occurrences = 0

 

REPEAT for all items in the list

IF current_item = search_item THEN

occurrences = occurrences + 1

END IF

END REPEAT

 

Display occurrences

 

Finding the Maximum/Minimum

This finds the largest and the smallest item in the list

Algorithm:

maximum = o

 

REPEAT for all items in the list

IF current_item > maximum THEN

maximum = current_item

END IF

END REPEAT

 

Display maximum

 

 

minimum = 999

 

REPEAT for all items in the list

IF current_item < minimum THEN

minimum = current_item

END IF

END REPEAT

 

Display minimum