The **mp4-box-encoding** library implements the abstract‑encoding API for parsing and constructing MP4 file boxes. It provides generic encoders/decoders that handle box headers and nesting, plus ready‑made leaf‑box encodings keyed by type, letting developers read, modify, and rewrite MP4 container structures (e.g., moov, stts) directly from buffers. It’s aimed at Node.js developers who need low‑level, stream‑friendly access to MP4 metadata without writing their own binary parsers.