CALM3encode

CALM3encode is a lossless data encoding algorithm and reference implementation designed to provide high compression efficiency and fast decode times for a variety of data types. The name denotes the third generation in the CALM encoding family, and the specification outlines a modular pipeline that can operate in software and hardware environments.

Its core design combines block-based processing with adaptive context modeling and arithmetic coding. Data is divided into variable-length blocks; for each block, a predictive model estimates symbol probabilities based on preceding context, generating refined probability distributions; these are encoded via arithmetic coding. An optional data integrity layer uses a lightweight error-detection code, and a stronger error-correction stage can be applied in noisy channels or archival storage.

CALM3encode originated from work by researchers at CALM Labs and was released as an open standard in 2023. A reference C++ implementation and bindings for Python and Rust were later published under an permissive license. The project emphasizes extensibility, enabling custom context models and data-type-specific optimizations.

Performance varies with data characteristics. Text and structured data with redundancy tend to achieve higher compression ratios, while already compressed media may see modest gains. The encoding process requires more memory and CPU than simple fixed-block schemes due to model maintenance, and real-time streaming demands careful block sizing.

CALM3encode has been adopted in experimental archival pipelines and some data-center toolchains. The standard is maintained by the CALM Alliance, which publishes compatibility notes and reference tests. Availability includes source code repositories and prebuilt binaries for major platforms under a permissive license.