Lossy v Lossless

• What is the purpose of compression in files?

  To reduce file size, download times, storage requirements, and make efficient use of bandwidth.
• Why is making efficient use of bandwidth important?

  Because of the vast amounts of data sent and streamed over the internet every day.
• How does compression speed up data transmission?

  By reducing the overall size of a file as much as possible.
• What are the two methods of compression discussed?

  • Lossy compression
  • Lossless compression
• What happens to a compressed file when it arrives at its destination?

  It needs to be uncompressed so it can be read again.
• How does color depth affect the size of an image file?

  The number of different colors increases the size of the file.
• How many bits are required to store two different colors in an image?

  One bit per pixel.
• How many bits are required to store four different colors in an image?

  Two bits per pixel.
• How many bits are required to store eight different colors in an image?

  Three bits per pixel.
• What is one way to reduce the file size of an image?

  By storing a lower number of colors or larger areas of pixels as a single color.
• What is the trade-off of using lossy compression methods?

  A small reduction in quality for a significant reduction in file size.
• Why is lossy compression considered an acceptable compromise?

  Because a small reduction in quality is not normally very noticeable to the human eye.
• What is the main advantage of lossless compression?

  It allows the original file to be recreated exactly when uncompressed.
• When is lossless compression particularly effective?

  On images with large areas of continuous colors, such as vector style images.
• For which types of files is lossless compression necessary?

  Text documents and executable programs.
• What are the key differences between lossy and lossless compression?

  • Lossy compression:
  • Some data is lost and cannot be recovered.
  • Slightly reduces quality but significantly reduces file size.
  • Suitable for multimedia files (image, audio, video).

  
  

  • Lossless compression:
  • No original data is lost; the original file can be recreated exactly.
  • Suitable for executable program files and text-based documents.