Lossy and lossless compression questions and answers
Q1. What is meant by ‘lossy’ compression?
A1. One type of codec is called 'lossy compression'. The maths formula for these seek to remove the parts of a file which are deemed relatively unimportant before compressing it. The parts that are removed are not normally noticeable by most people.
Q2. What is meant by ‘lossless’ compression?
A2. Lossless codecs keep all of the information about a file. The compressed file, once decompressed, can be reconstructed so it is exactly like the file before it was compressed, with no loss of any information at all. This would be very important if you needed to get access to the highest quality file possible, the original file, without any loss of data.
Q3. Give an example of picture file type which uses lossy compression.
A3. JPG.
Q4. Give an example of picture file type which uses lossless compression.
A4. PNG.
Q5. Give an example of sound file type which uses lossy compression.
A5. MP3.
Q6. Give an example of sound file type which uses lossless compression.
A6. FLAC.
Q7. Give an example of video file type which uses lossy compression.
A7. MPEG4.
Q8. Give an example of video file type which uses lossless compression.
A8. Huffyuv.
Q9. What is a codec?
A9. A codec is a maths formula that is applied to a raw picture, document, sound or video file to strip out 'unnecessary' parts and therefore make the file much smaller.
Q10. Why not just use the raw files rather than apply a codec to them to convert them into a different format?
A10. Raw files are foten very large. They can use up a lot of storage space, take a long time to load up in browsers and other software and can take a long time to transmit across networks.