Compression (OCR GCSE Computer Science): Flashcards
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Practise the cards
13 cards from this deck
Why use compression?
Why use compression?
Reduce file size for easier storage & transfer
What is lossy compression?
What is lossy compression?
Permanently removes some data to reduce file size
Examples of lossy compression formats
Examples of lossy compression formats
JPEG, MP3, MP4
Main disadvantage of lossy compression
Main disadvantage of lossy compression
Quality lost; original can't be perfectly restored
What is lossless compression?
What is lossless compression?
Reduces file size without losing any data
Examples of lossless compression formats
Examples of lossless compression formats
ZIP, PNG
Main advantage of lossless compression
Main advantage of lossless compression
File can be restored to its original state
What are bitmap images made of?
What are bitmap images made of?
Tiny squares called pixels
What is a pixel?
What is a pixel?
Smallest unit of an image, stores one colour as binary
What is colour depth?
What is colour depth?
Number of bits used to represent colour of each pixel
How many colours can 4 bits store?
How many colours can 4 bits store?
16 colours
What is resolution in an image?
What is resolution in an image?
Number of pixels in an image
How to convert bits to bytes?
How to convert bits to bytes?
Divide by 8