MediaSeg is a local macOS utility that splits large media files into upload-ready chunks for practical, size-limited workflows. It is useful for NotebookLM-style uploads and similar destinations, and now officially supports MP4, WEBM, and MOV, with M4A, MP3, and WAV available as experimental support. Recent updates also added theme and language support.
Looking beyond MediaSeg? Try FFmpeg for CLI power and formats, Compresto or Clop to shrink files fast, plus Screen Studio and Tella if you’re recording before slicing uploads.