Compression Flashcards

All 12 cards in this deck

Give two reasons why files are compressed.

They take up less storage space, and they need fewer packets so transmit faster across a network.

Give two scenarios where compression would be needed.

Streaming or downloading high-definition video, and emailing or uploading large audio or image files.

What is lossy compression?

Compression that reduces file size by permanently removing data, so the original cannot be fully recovered.

What is lossless compression?

Compression that reduces file size without losing any detail, so the file can be restored to its original quality.

What is run length encoding?

A lossless compression method that stores a run of repeated data as the data item and the number of times it occurs.

True or false? Lossless compression reduces file size more than lossy compression.

False. Lossy achieves the greater file size reduction; lossless keeps all the data.

Which types of file must be compressed using lossless compression?

Text files, spreadsheets, financial records and emails, where no data may be lost.

Which type of compression does the JPEG format use?

Lossy compression.

Which type of compression does the MP3 audio format use?

Lossy compression.

Which type of compression does the MPEG video format use?

Lossy compression, which makes it suitable for streaming media.

Which type of compression does the GIF image format use?

Lossless compression (an 8-bit format that can also store short animations).

Which type of compression does the PDF format use?

Lossless compression, used for text documents.