Lossy Compression | 2.5 | OCR GCSE Computer Science | J277

8 flashcards

Lossy compression

Compression by which data is permanently removed in order to reduce file size. The original file can never be fully restored.

What is an affect of the original file never being able to be fully restored?

A noticeable loss in the quality.

How can lossy compression reduce the file size of an image?

By reducing colour depth and/or resolution.

How can lossy compression reduce the file size of a video?

By removing very high/low frequencies that humans cannot hear.

Advantage - why does lossy compression result in a smaller file size than lossless compression?

Because in lossy compression, data is permanently removed, saving storage space.

Advantage - Why is lossy compression good for media files?(image, video, audio)

Because perfect accuracy is not needed.

Disadvantage of lossy compression

- Data is permanently removed and cannot be restored, leading to a noticeable loss in quality.

Disadvantage - Why is lossy compression unsuitable for text and software files.

Permanently removing data results in the file becoming incomprehensible.