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Chapter :one: - Digital Data (Representing Images (buffering and streaming…
Chapter :one: - Digital Data
Representing Data
Information & Data
data consists of raw facts and figures with no meaning or context attached
when data is processed (or given a meaning) it is described as information.
therefore, information is described as "data with a meaning"
storing data
computers store data in digital format. A
Binary digIT
(or bit) has the value of 1 or 0 and is the smallest unit of computer storage
a single character (such a s a letter or digit) is represented at 1 byte (or 8 bits)
1 nibble = 4 bits
2 nibbles = 1 byte
1 byte = 8 bits
1024 bytes = 1 kilobyte (KB)
1024 kilobytes = 1 megabyte (MB)
1024 megabytes = 1 gigabyte (GB)
1024 gigabytes = 1 terabyte (TB)
these terms are usually used to describe data storage capacity and computer memory :
Data Types
Numeric
integar numbers
- can be positive/ negative. Only whole number
Real numbers
- include whole numbers and number with a decimals/ fractions parts. can be positive or negative
Date/ Time
determines the way the date/ time appears on display
e.g.
Long date - Saturday, April 1, 2018
Medium date - dd/mmm/yyyy (1-Apr-2018)
Short date - dd/mm/yyyy (01/04/2018)
Long time - hh:mm:ss (13:26:34)
medium time - hh:mm AM/PM (01:26 PM)
Short time hh:mm (13:26)
Character/ String
a character is a single letter or digit represented by codes from the character set up used y the computer [such as ASCII]
a string is textual data in the form of a sequence of characters from a character set [such as a word]
Representing Images
a pixel is the smallest unit of digital image that can be displayed and edited on a computer screen
Image
resolution
tells us the quality of an image. The greater the number of pixels used in an image, the higher the resolution and sharper the image.
Bitmap and vector-based graphics
Bitmap graphics
made up of a grid of pixels
the higher the resolution, the higher the quality
requires more storage
store details about every individual pixel
vector-based graphics
based on mathematical objects such as lines, curves and shapes
requires less storage capacity
can be enlarged and not lose image quality
possible to edit shaped individually
buffering and streaming a video
streaming
is a process that that allows a video to be viewed on a website/app straight away without waiting for the video to be downloaded
when using streaming, the user can start watching the video as it downloads in
"realtime"