Lossy vs Lossless compression
1.3.1 Compression, Encryption and Hashing
Compression, Encryption and Hashing — Note 1 of 4
Candidates need to understand the need for compression, especially when transferring data via the Internet. Candidates need to understand the difference between lossy and lossless compression, and the benefits and drawbacks of each type. Candidates need to be able to recommend a type of compression for a given scenario.
Compression reduces the size of a file, which saves storage space and reduces the time and bandwidth needed to transmit it, especially over the Internet. Lossy compression permanently removes data; lossless compression allows the original to be rebuilt exactly.
Encoding data so that it uses fewer bits than the original.
Permanently removes data that is judged least noticeable to humans. The original cannot be recovered, but file sizes are much smaller.
Reduces file size by encoding patterns more efficiently. No data is lost and the original can be reconstructed exactly.