Chapter 1 (1.1, 1.2, 1.3) Data representation Flashcards by Neel Saraf

What is Pixel

The smallest element used to make up an image on a display.

How well did you know this?

Not at all

Perfectly

What is an image

a series of pixels that are converted to binary, which is processed by a computer

How well did you know this?

Not at all

Perfectly

What is Colour depth

The number of bits used to represent the colours of a pixel.

How well did you know this?

Not at all

Perfectly

What is Image resolution

The total number of pixels that make up an image.

How well did you know this?

Not at all

Perfectly

File size of an image

Image resolution * colour depth

How well did you know this?

Not at all

Perfectly

What is Sample rate

Number of samples taken per second

How well did you know this?

Not at all

Perfectly

What is sampling resolution

The number of bits used to represent sound amplitude in a digital sound recording.

How well did you know this?

Not at all

Perfectly

What is lossy compression

The file compression algorithm eliminates unnecessary data from the file. This means the original file cannot be reconstructed once it has been compressed. Eg: MP3, JPEG

How well did you know this?

Not at all

Perfectly

What is bit depth

Number of bits used to represent the smallest unit in a sound file

How well did you know this?

Not at all

Perfectly

How to calculate file size of a mono sound file

Sample rate * sample resolution * length of sample * number of channels

How well did you know this?

Not at all

Perfectly

What are the two types of compression

Lossy
Lossless

How well did you know this?

Not at all

Perfectly

What is a bit

Basic computing Element that is either 0 or 1.

How well did you know this?

Not at all

Perfectly

What is compression

Reduction in file size by removing or reorganising redundant or repeated pieces of data

How well did you know this?

Not at all

Perfectly

What happens when lossy compression is applied

to an img
to a sound file

img - reduce the resolution and/or the bit/colour depth

sound - reduce the sampling rate and/or the resolution.

How well did you know this?

Not at all

Perfectly

What is lossless compression

A file compression method that reorganises runs of data to compress the file. The original file can be fully restored.

How well did you know this?

Not at all

Perfectly

What is Run Length Encoding

A lossless file compression technique is used to reduce the size of text and photo files in particular

What is an error code

Error messages that contain numbers that refer to the memory location of the error and are usually automatically generated by the computer

What is ASCII code

A character set for all the characters on a standard keyboard and control codes.

What is Unicode

A character set which represents all the languages of the world

Applications of hexadecimals

MAC Address
IP Address
Representing colours
Error codes

What is an overflow error

When there are more bits than the register can handle

What directions means what operation in Binary Shifting

Right shift = division
Left shift = multiplication

What is the MAC address

Uniquely identifies a device on the internet

How many bits does the MAC address have?

48 bits - 6 pairs of hexadecimal values

What is the IP address

Gives a unique address to each device connected to a network identifying their location

IPv4

32 bit number separated by '.'

IPv6

128 bit number separated by ':' 16 bit chunks (4 hex numbers:4 hex numbers)

MP3 sound files

A form of lossy compression where the original file size is reduced by 90% Lossy compression removes frequencies outside human hearing range Perceptual music shaping

What is perceptual music shaping

If two sounds are playing at the same time, the softer one is removed.

JPEG

Lossy file compression. Bitmap image which is very large becomes a JPEG file after lossy compression Human eyes can't detect changes in colour as well as brightness. Separates pixel colour from brightness, images can be split into 8 x 8 pixel blocks, and allows certain information to be discarded

MP4

Similar to mp3 except mp4 allows videos, photos, animations and music. perceptual music shaping remove repeated frames

Why data is compressed

»save storage space »reduce the time taken to stream a music or video file »reduce the time taken to upload, download or transfer a file across a network »reduced file size also reduces costs

How to convert from binary to denary

Each value in the binary number is a power of 2 1 1 1 1 8 4 2 1

How to convert from denary to binary

Subtract powers of 2 until remainder is 0 12 in binary is 12- 8 = 4 -4 = 0 1100

How to convert binary to hexadecimal

take binary in groups of 4 and see what denary value they have convert that denary value of hex eg 1111000011111 1111 | 0000 | 1111 15 | 0 | 15 F0F

How to convert hex to binary

convert each digit to groups of 4 binary digits

Benefits of using a larger sampling resolution

larger dynamic range better sound quality less sound distortion

how much is 1 (in bytes): kibibyte mebibyte kilobyte megabyte

KiB 2^10 MiB 2^20 KB 10^3 MB 10^6