Losslesskodning

Losslesskodning, also known as lossless compression, is a type of data compression in which the original data can be perfectly reconstructed from the compressed data. This is in contrast to lossy compression, where some data is lost during the compression process, resulting in a smaller file size but a reduction in quality.

Lossless compression algorithms work by identifying and eliminating statistical redundancy in the data. For example, in a text file, the letter 'e' might appear much more frequently than the letter 'z'. A lossless compression algorithm can assign a shorter code to the letter 'e' and a longer code to the letter 'z', thereby reducing the overall file size. Common lossless compression techniques include Huffman coding, Lempel-Ziv algorithms (such as LZ77 and LZ78), and run-length encoding.

Lossless compression is particularly important for data where perfect fidelity is crucial, such as text documents, computer programs, medical images, and archival purposes. While the compression ratios achieved with lossless methods are typically lower than those of lossy methods, they guarantee that no information is lost. Examples of file formats that often use lossless compression include PNG for images, FLAC for audio, and ZIP for general file archiving. The trade-off for perfect reconstruction is a larger file size compared to lossy compressed equivalents.