encoding

Encoding is the process of converting information from one form into another for storage or transmission. It is typically reversible, allowing the original data to be recovered by decoding. Encoding is distinct from encryption, which aims to obscure content, and from compression, which reduces size through data reduction.

Character encoding maps abstract characters to concrete byte sequences. Common standards include ASCII, ISO/IEC 8859, and Unicode encodings such as UTF-8 and UTF-16. UTF-8 is widely used because it preserves ASCII compatibility and supports all Unicode code points. Mismatched encoding can produce garbled text (mojibake).

Data encoding refers to representing binary data or text in a form suitable for transmission or storage. Examples include Base64, hexadecimal, and URL encoding. These encodings enable safe passage through text-based protocols and channels, and they are designed to be lossless so the original data can be recovered.

Media encoding applies to audio and video streams. Codecs such as MP3, AAC, H.264, and AV1 compress or transform data to reduce bandwidth while attempting to preserve perceptual quality. Encodings can be lossless or lossy, and choices depend on quality, latency, and compatibility with playback software and hardware.

Standards bodies define encoding schemes to enable interoperability across systems.