Subler

Subler is a macOS utility for combining and annotating MP4 containers. It can merge video, audio, chapter, subtitle, and closed‑caption tracks from source files in MOV, MP4, or MKV formats, as well as raw streams such as H.264, AAC, AC‑3, Scenarist and VobSub. The application also creates subtitle tracks in TX3G and WebVTT that are compatible with Apple devices and QuickTime.

In addition to muxing, Subler offers full iTunes‑style metadata editing. Users can manually edit fields or retrieve information automatically from TheMovieDB, TVDB, and the iTunes Store for movies and TV shows, ensuring that the resulting MP4 files carry appropriate titles, artwork, and descriptive data.

The software is targeted at macOS users who need to prepare MP4 files for playback on Apple hardware or for distribution with complete metadata and subtitle support. It runs on macOS 10.13 or later and is classified as stable.