Images and Sound 1.2

Question 1

types of image files - bitmap

Answer 1

BMP

JPG

GIF

PNG

TIFF

Question 2

types of image files - vector

Answer 2

SVG

Question 3

Bitmap images

Answer 3

-made from pixels

Question 4

pixel is given

Answer 4

• a colour
  -binary number which represents that colour

Question 5

image resolution

Answer 5

the concentration of pixels within a
specific area

Question 6

Increasing the number of colours in bitmap

Answer 6

More bits per pixel =
more colour combinations

Question 7

bit depth

Answer 7

number of colours

Question 8

higher bit depth

Answer 8

better variety of colours

Question 9

bit depth formula

Answer 9

2 to the power of n
n = bits

Question 10

size of a bitmap image

Answer 10

measured in pixels (width x height).

Question 11

colours in pixel

Answer 11

Each pixel has a proportion
of red, green and blue
-makes one colour

Question 12

colour values

Answer 12

expressed in
software as denary RGB values and in hexadecimal

Question 13

metadata

Answer 13

Colour depth in bits per pixel

Resolution (Height and width in pixels)

Date created

Author

Question 14

pros of colour values being in hex

Answer 14

-easier to read/write = reduces errors

Question 15

RGB value range

Answer 15

-0 to 255
-each colour must be 8 bits to store range

Question 16

entire pixel bit range

Answer 16

3 * 8 = 24 bits

Question 17

transparency channel

Answer 17

-32 bits per pixel 8 bits are given
-allow a background to show through

Question 18

image size in bits

Answer 18

width * height * colour depth

Question 19

image size in bytes

Answer 19

(width * height * colour depth) /8

Question 20

analogue sound signals are

Answer 20

continuous

Question 21

Digital signals are

Answer 21

discrete

Question 22

how is Sound digitized

Answer 22

by repeatedly measuring and
recording the sound wave

Question 23

A to D converters

Answer 23

Sounds is converted to a digital form
= stored + processed by a computer

Question 24

An Analogue to Digital Convertor (ADC)

Answer 24

is used to
convert inputs to digital signals

Question 25

A Digital to Audio Convertor (DAC)

Answer 25

is used to
convert digital signals to outputs

Question 26

sound sampling

Answer 26

measurement of amplitude of a
sound wave at a given time

Question 27

how is sound sampled

Answer 27

-sample resolution (bit depth)
-sampling rate

Question 28

sampling rate

Answer 28

number of samples taken per second
(Hz)

Question 29

Sample resolution

Answer 29

The number of bits used to record
each measurement

Question 30

More bits used per sample =

Answer 30

• the height of the wave to be more accurately measured
• increases file size

Question 31

Hertz

Answer 31

1Hz = 1 sample per second

Question 32

sampling rate frequency

Answer 32

The greater the frequency, the greater the accuracy, and file size

Question 33

Calculating sound file sizes

Answer 33

sample rate x bit depth x duration

Question 34

Recording quality improves:

Answer 34

the more frequent
the more accurately recorded the wave height

Question 35

Increasing the sampling rate (frequency) =

Answer 35

means
recording more data points

Question 36

Increasing the bit-rate =

Answer 36

improves the accuracy of each
data point

Question 37

Lossy compression

Answer 37

removes sounds that
we can’t easily hear or that is unecessary

Question 38

Lossy compression cons

Answer 38

-leaves out some data
=affects quality

Question 39

Lossy compression pros

Answer 39

useful for storing,
downloading or streaming
-as it is smaller

Question 40

Lossless compression

Answer 40

-reduce the file size
when compressed but do not
lose any information
-can be decompressed

Question 41

eg of lossless

Answer 41

FLAC (Free Lossless Audio Codec)

ALAC (Apple Lossless Audio Codec)

WMA Lossless
(Windows Media Audio)