01b- Representing Sound

Question 1

Define pixels.

Answer 1

A pixel is the smallest unit of an image. Usually represented by a dot.

Question 2

Define colour depth.

Answer 2

Colour depth refers to the number of bits to represent a specific colour.

Question 3

What is true colour?

Answer 3

Twenty-four bits

Question 4

What is the relation between the number of colours that can be stored depending on the number of bits used for each colour.

Answer 4

The number of bits indicates how many colours are available for each pixel.

Question 5

How do you calculate the colour depth?

Answer 5

E.g. 2 bits per pixel:
4 colours (2^2)

8 bits per pixel:
256 colours (2^8)

Question 6

Define resolution.

Answer 6

Resolution is a measurement of the clarity and quality of the image.

Question 7

How do you get a higher resolution?

Answer 7

The greater the number of pixels in the smaller the space will lead to a higher resolution. Measured in PPI (Pixels Per Inch)

Question 8

What are the effects of higher resolution images?

Answer 8

• Large number of pixels in small spaces
• Clear and realistic images can be stored
• Larger File Size as every pixel’s colour code has to be saved
• Higher resolution image
• Longer loading and processing time on the computer

Question 9

What is a Bitmap?

Answer 9

• Bitmap graphic is stored as a grid of pixels.
• You need to store the binary colour code, the width, height and colour depth
• Stored as a grid of pixels. All components of the image are deconstructed into pixel patterns.
• When stretched the image can become blurred
• Bitmap files take a long time to load
• Typical uses of Bitmaps:
  Most web graphics
  HI-RES Files

Question 10

What is a Vector?

Answer 10

• Vectors are made up of lines, curves and points. Object is defined by mathematical equations
• Can be resized without becoming blurry
• Typical uses of Bitmaps:
  For logos
  Charts
  Icons

Question 11

Define buffering?

Answer 11

An intermediate storage area used to hold the download segments of a video file that haven’t been played.

Question 12

Define streaming?

Answer 12

A process that allows videos to be viewed without having to wait for the full video to download.

Question 13

Explain Analogue to Digital Conversion.

Answer 13

• Microphone measures the change in air pressure
• The Microphone translates the air pressure into a sound wave
• An Analogue-Digital Converter will sample the sound wave at intervals, storing each sample in a number of bits. The amount of samples that are taken is called the Sample Rate and the number of bits used for each sample is known as the Bit Depth.
• A computer will understand and can display the digital information for playback or manipulation.

Question 14

Define Sample Rate.

Answer 14

The amount of samples that are taken is called the Sample Rate. (measured in hertz)

Question 15

Define Bit Depth.

Answer 15

The amount of bits used for each sample.

Question 16

What is Bit Rate?

Answer 16

Bit Depth x Sample Rate

The Bit Rate of a file tells us how many bits of data are processed every second.