IB Computer Science Topic A1.1.8: Concept of Compression Key Definitions

Compression is the process of reducing the size of data files to save storage space and improve transmission efficiency.

Lossless compression runs an algorithm to compress the data, the algorithm can then be reversed to restore the data. This ensures that the original data can be perfectly reconstructed from the compressed version.

Lossy compression reduces file size by discarding some data that is less noticeable or redundant, resulting in an approximation of the original content.

Run-Length Encoding (RLE) is a lossless data compression technique that replaces consecutive repeating occurrences of a symbol with a single instance of the symbol followed by a count of its repetitions.

Transform coding is a lossy compression technique that converts data from the spatial or time domain into a different mathematical representation, typically using frequency-based transformations like the Discrete Cosine Transform (DCT) or Discrete Wavelet Transform (DWT).