Data compression (Edexcel GCSE Computer Science): Flashcards
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Data compression definition
Data compression definition
Using algorithms to make files smaller
Main purpose of data compression
Main purpose of data compression
Reduce file sizes for storage & faster transfer
Two main types of data compression
Two main types of data compression
Lossless and lossy
Lossless compression characteristic
Lossless compression characteristic
No data lost; original fully recoverable
How lossless compression works
How lossless compression works
Finds patterns & redundancy, groups repeated data
Examples of lossless formats
Examples of lossless formats
ZIP, GIF, PNG, FLAC, ALAC
Lossy compression characteristic
Lossy compression characteristic
Throws away some data permanently
Lossy compression for images method
Lossy compression for images method
Similar colours given same value, reduces bits needed
Lossy compression for audio method
Lossy compression for audio method
Removes quiet sounds & frequencies humans can't detect
Examples of lossy formats
Examples of lossy formats
MP3, JPG/JPEG
Storage benefit of compression
Storage benefit of compression
Less space needed, more files fit on devices
Internet benefit of compression
Internet benefit of compression
Faster download/upload speeds, less bandwidth used
MP3 file size vs uncompressed audio
MP3 file size vs uncompressed audio
About 1/10th the size
Uncompressing lossless vs lossy result
Uncompressing lossless vs lossy result
Lossless: identical. Lossy: close but not identical