GCSE Computing/The differences between lossy and lossless compression

Lossless versus lossy compression Summary It is often necessary to compress a file to make it small enough to be used - for example making a music file small enough so that enough can be stored on an iPod. There are two main possibilities: Lossless These are used to make a file a smaller size but without losing any of the information. Using this method you can always get back to the original file Lossy Sometimes some loss of quality is acceptable. For example the human ear cannot hear all frequencies, so a file format that throws away parts that people can't hear may end up with a smaller file, but it is not possible to get back to how exactly the original music sounded. Which format to choose? The only real reason for choosing a lossy format is because the file would be too big if you used a lossless one. For example, a lossless picture may be too big to download in a sensible amount of time, or you could store many less tracks on an iPod if you used a lossless format instead of AAC or MP3. Another factor to choose lossy or lossless compression may be the computational power needed (and the time). Examples Lossless Compression Portable Network Graphics Tagged Image File Format Flac Lossy Compression MP3#Development JPEG#JPEG compression