dataencoding

Data encoding is the process of converting information from one representation to another for storage, transmission, or processing. Encoding focuses on how data is represented and decoded back, and is distinct from encryption, which hides content, and from compression, which reduces size. A correct encoding allows consistent interpretation across systems and time.

Character encodings map abstract characters to byte sequences. Common systems include ASCII, ISO/IEC 8859-1, and Unicode encodings such as UTF-8, UTF-16, and UTF-32. UTF-8 is widely used on the Internet because it preserves ASCII compatibility and uses a variable-length format. Endianness and byte order marks (BOM) affect how multi-byte encodings are stored. Other data encodings convert binary or other data into text-friendly forms, for example base64, hexadecimal, and URL (percent) encoding. These are used to embed binary data in text streams, to simplify transport in protocols, or to ensure safe inclusion in identifiers and URLs.

In multimedia and data transmission, encoding also refers to the choice of codecs or representations used to compress or transform data for a given medium. Examples include MP3 or AAC for audio, H.264 for video, and various lossless or lossy techniques. In all cases, the encoder must be paired with a decoder that understands the same format.

Key considerations when selecting an encoding include compatibility with recipients, efficiency, error detection, and the likelihood of visibility in logs or interfaces. Mismatches in character encoding commonly cause garbled text, known as mojibake, highlighting the need for explicit charset declarations in software and documents.