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Encoding Images and Sound, n - Coggle Diagram
Encoding Images and Sound
Images
Made of
pixels
Pixels are the smallest unit of an image
All pixels have a binary code
Example: Black and White image
Black=0 and White=1
Colour depth
The number of bits per pixel
That are needed to represent a colour
Formula to work out colour depth
Total number of colours= 2
n=number of bits per pixel
Example: 3 bit image: 2³ =8 colours
How to work out the number of colours that can be made
Resolution and Metadata
Metadata
Information about information
The information stored about an image, e.g.:
File size
The height and width (dimensions)
File name
Geographical coordinates
Resolution and Colour Depth
Resolution:The number of pixels in an image
A high resolution means:
A clearer image
More pixels, so a larger file size
Sound
Sample frequency
How many samples are taken in a second (Hz/kHz)
Represented as Analogue wave
Needs to be converted from analogue to digital for computers to understand
This is done by an analogue to digital converter
The process of conversion is called '
Sampling
'
Analogue=Continually changing
Bit depth
is the number of bits available for each audio sample.
How to calculate size of a sound file:
Sample rate×bit depth×length
Increasing sample rate or bit depth= increasing file size
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