* [go-mp4 v1.5.0](https://github.com/abema/go-mp4) – Go library providing low-level read/write and box-level parsing/building of MP4 files. * [mp4ff v0.51.0](https://github.com/Eyevinn/mp4ff) – Library and tools for parsing and writing fragmented and progressive MP4 files with support for multiple video, audio, subtitle, and metadata codecs.