audioencoding

Audio encoding is the process of converting digital audio data into a coded representation suitable for storage or transmission. It typically starts from sampled and quantized audio, and aims to reduce data size while preserving perceptual quality. Encoding is paired with decoding, which reconstructs playable audio from the coded form.

There are two broad families: lossless and lossy. Lossless encoders preserve the exact original data, allowing perfect reconstruction, and are used for archival and high-fidelity applications. Examples include FLAC, ALAC, and lossless variants of WAV or AIFF. Lossy encoders discard some information deemed inaudible or unnecessary to human hearing to achieve higher compression. Common lossy formats include MP3, AAC, Ogg Vorbis, and Opus; these rely on perceptual models to remove data that has minimal perceived impact.

Bit rate and quality are central considerations. Lossless encoding maintains bit-perfect reproduction, with compressed sizes typically close to the original file size. Lossy encoding achieves higher compression, with bitrates that can vary widely depending on desired quality and application. For example, music files using MP3 or AAC often range from about 128 to 320 kbps, while Opus can operate effectively at much lower bitrates for speech and interactive media.

The encoding process involves selecting sampling rate and bit depth, applying a source coder, and producing a bitstream that may be wrapped in a container format (such as WAV, AIFF, MP4, or MKV) and annotated with metadata. Encoding decisions are influenced by target devices, bandwidth, latency, and licensing or compatibility considerations. Encoded audio is used in music distribution, streaming, broadcasting, and archival contexts.