Past paper Questions

Home Forums Data Compression Past paper Questions

Viewing 5 posts - 1 through 5 (of 5 total)
  • Author
  • #7056

    dentify two different types of file which, if compressed, could make use of a lossy compression algorithm.

    Evaluate lossy compression and lossless compression when used to download files. [4]

    Discuss two factors that would affect the decision to use either lossless or lossy compression when transferring across the Internet.


    1. video and images
    2. Both make downloading files take less time than if the file didn’t using any compression method. Both take less storage space than if the file didn’t use a compression method.
    However lossy is fundamentally going to be smaller than lossless. Because lossy removes data, whilst lossless simply uses different methods to store the data in a way it takes less information to process when it needs to without actually removing actual data from the file that actually altars how it is.
    3. If the small details in the file don’t matter and only the overall file does then it can use lossy compression. If the small details matter then lossless compression. If the connection is weak then taking the time to compress would be better than if it is a strong one where data transfer uncompressed wouldn’t make much difference.
    so in conlcusion:
    a. if the small data in the file matter or not
    b. and if the internet connection is reliable or not

    Shiva Chandnani

    1. Audio files and images
    2. When using lossy and lossless compression to download files, it will result in taking less time to download and taking up less of the users data storage. Lossy compression usually is stored in less data that lossless. Lossy compression results in the size of the file being reduced by eliminating data in the file. Lossless compression is such that it does not lose any data in the compression process. Lossless compression “packs” data into a smaller file size by using a kind of internal shorthand to signify redundant data.
    3. If all data on the file is important to the user and they do not want to lose any of that information then a lossless compression is more important.Another factor to use lossless compression would be if the user is not short on data storage space and doesn’t mind the file taking up extra space on their computer.


    1. Image and audio files
    2. The difference between lossy and lossless compression when used to download files are data. Lossy compression reduces the file size by deleting the data in the file. The lossless compression on the other hand does not delete them, but rather stores data differently. Instead of deleting, it simplifies the data so that it is easier to be processed by packing redundant data. The similarities are that it takes less time to download and takes up less storage.
    3. The first factor is the importance of the data and whether losing it would be a big risk. If the file is important, then lossless compression would be the better choice.
    Another factor is the speed of the file to be transferred at. If a file needs to be transferred fast, lossy compression would be the better choice.


    1. images and audio
    2. Lossy compression results in file sizes being reduced permanently meaning that data is lost permanently but in lossless the file size is reduced during compression but all the original data can be recovered after decompression. However both types of compression can help reduce data storage and bandwidth consumption.
    3. Importance of the data: Files where losing data would be significant shouldn’t be compressed using lossy rather should use lossless.
    Speed: But if there needs to faster transfer data lossy will be more preferred over lossless

Viewing 5 posts - 1 through 5 (of 5 total)
  • You must be logged in to reply to this topic.
Scroll to Top