1.2.5 - Compression Flashcards
What is compression?
Reducing the size of a file so that it takes up less storage space. Either Lossy of Lossless.
What are the benefits of compression?
Takes up less storage space,
Files can be transferred faster (as they are smaller),
Files can be read from or written to quicker.
What are some common scenarios where compression may be needed?
Sending files via email,
Uploading files to the internet,
Reducing storage usage on devices.
What is lossy compression?
When data is lost to reduce the file size, and is never recoverable and is permanent.
Suitable for images, sound and video.
What is lossless compression?
When the file size is reduced, without permanently removing/losing any data.
What are the advantages of lossy compression?
Greatly reduces the file size,
Suitable for images, sound and video and has a faster download time.
What are the disadvantages of lossy compression?
Loss of quality,
Original file cannot be restored,
NOT suitable for text and executable files.
What are the advantages of lossless compression?
No data is lost,
Original file can be perfectly recovered.
Can be used on ALL data types.
What are the disadvantages of lossless compression?
Less reduction in file size compared to lossy. (less effective)
File size often stays larger.
What effect does lossy compression have on a file?
Removes unnecessary data,
Reduces quality,
Cannot restore original version.
What effect does lossless compression have on a file?
Reduces file size without losing any information,
File can be restored exactly to its original state
