Unit 1: Information Representation and MultiMedia

Comprehensive practice flashcards covering Unit 1: Information Representation and MultiMedia, including number systems, binary calculations, bitmap vs vector graphics, sound sampling, and compression techniques.

What is the base of the Denary number system?

Base 10, using digits 0 through 9.

What is the base of the Binary number system?

Base 2, using digits 0 and 1.

What is a bit in computing?

A binary digit, which is the smallest unit of data in computing.

What do the binary digits 1 and 0 represent in a computer processor's transistors?

They represent the on and off states of a transistor switch.

What is a byte?

A group of 8 bits.

What is a nibble?

Half a byte, which consists of 4 bits.

According to internal memory conversion rules, how many Bytes make up a Kilobyte, Megabyte, and Gigabyte?

1 Kilobyte is 1024 Bytes, 1 Megabyte is 1024 Kilobytes, and 1 Gigabyte is 1024 Megabytes.

According to the IEC convention for internal memories, how many Bytes are in 1 Kilobyte and 1 Megabyte?

1 Kilobyte is 1,000 Bytes and 1 Megabyte is 1,000,000 Bytes.

How is a positive binary number identified in its most significant bit?

It always starts with 0.

How is a negative binary number identified in its most significant bit?

It always starts with 1.

What is One's Complement?

A system where each digit in a binary number is inverted.

What is Two's Complement?

A system where a binary digit is added into the One's Complement.

What causes an overflow error in binary arithmetic?

When the largest number that a register can hold is exceeded.

What is meant by word size?

The number of bits that a register can handle.

What is a Bitmap image?

A system that uses pixels to create an image.

What are pixels?

The smallest picture elements that are grouped together to make an image.

What is Colour Depth?

The number of bits used to represent colors in a pixel.

What is Image Resolution?

The number of horizontal and vertical pixels that make up an image.

What is Screen Resolution?

The number of horizontal and vertical pixels that make up a screen display.

What is Pixel Density?

The number of pixels in a square centimetre.

What are Vector Graphs?

Images that use 2D shapes to represent lines and curves and their properties to form geometric shapes.

What is Sampling Resolution?

The number of bits used to represent a sound sample.

What is Sampling Rate?

The number of sound samples per second.

What is Frame Rate?

The number of video frames that make up a video per second.

Why does picture quality decrease when zooming in on a bitmap image?

The pixels are stretched into larger dots.

What information is included in an image file header?

Information such as file size, number of colors, image resolution, color depth, and type of compression.

What is the formula for calculating Total Pixels in an image?

$$\text{Total Pixels} = \text{Width} \times \text{Height}$$

What is the formula for calculating Image File Size?

$$\text{File Size} = \text{Total Pixels} \times \text{Colour Depth}$$

How are 24-bit coloured images typically coded?

They use 8 bits for Red, 8 bits for Green, and 8 bits for Blue RGB.

Why do vector images tend to have smaller file sizes than bitmap images?

Vector images only store mathematical formulas, whereas bitmap images store color information for each individual pixel.

What is SVG?

Scalable Vector Graphics, a markup language format that maintains quality regardless of zoom level.

What is a Drawing List in vector graphics?

A set of commands used to define a vector image.

What happens when a monitor or printer displays a vector image?

It is rasterised, meaning it is converted into a grid of pixels.

What is the speed of a sound wave spreading out in air as given in the notes?

$3.4 \times 10^2\,\text{m/s}$ or $340\,\text{m/s}$

What are the two components of a sound encoder?

The Band limiting filter (to remove high-frequency components) and the ADC (Analogue-to-digital converter).

What are the steps involved when sound is captured through a microphone?

1. Microphone measures change in air pressure. 2. Microphone translates air pressure into electrical voltage. 3. ADC digitises the electrical voltage to bytes. 4. Computer displays the digitised sound.

What formula calculates Audio Bit Rate?

$$\text{Bit Rate} = \text{Sampling Rate} \times \text{Sampling Resolution}$$

What is Lossless Compression?

A compression method where file size is reduced while audio quality remains the same, allowing data to be perfectly reconstructed.

What is Run-Length Encoding?

A lossless compression technique in which sequences with the same data value in consecutive positions are stored as a single data value and count.

What is Lossy Compression?

A compression method that permanently removes data to reduce file size, making it impossible to recreate the original file.

What is Perceptual Coding?

A lossy coding technique that reduces certain parts of a sound that are less audible to human hearing.