1.3 Compression Cambridge iAS 9618

Why is compression used in digital files?

• To reduce file size for storage and transmission

• To increase the resolution of an image

• To add encryption to a file

• To improve sound quality

Which of the following is a key difference between lossy and lossless compression?

• Lossy compression removes some data permanently, while lossless retains all data

• Lossy compression makes files larger, while lossless makes them smaller

• Lossy compression is only used for images, while lossless is used for text

• Lossy compression is reversible, while lossless is not

Which type of file is most commonly compressed using lossy compression?

• A JPEG image

• A ZIP archive

• A text document

• A database file

Which two file formats are typically compressed using lossless compression?

• PNG

• MP3

• JPEG

• GIF

What is a disadvantage of lossy compression?

• Some original data is lost and cannot be recovered

• The file size increases after compression

• It does not work on images and audio files

• It is slower than lossless compression

Why might lossless compression be used instead of lossy compression?

• When it is important to retain all original data

• When reducing the file size as much as possible is necessary

• When compressing high-resolution photographs

• When converting an image to grayscale

What is an example of a file type that should use lossless compression?

• A text document

• A music file

• A video file

• A low-resolution photograph

What does Run-Length Encoding (RLE) do?

• It replaces sequences of repeating data with a count and a single value

• It removes parts of an image to reduce file size

• It converts text files into binary code

• It encrypts data to make it secure

How does RLE work in bitmap image compression?

• It stores consecutive identical pixels as a single value and a count

• It reduces the number of colors in the image

• It converts the image into a vector format

• It increases the resolution of the image

Which type of image is best suited for Run-Length Encoding (RLE) compression?

• An image with large areas of the same color

• A high-resolution photograph

• A vector-based drawing

• A scanned document with mixed text and images