WWDC 2020: Author Fragmented MPEG-4 Content With AVAssetWriter


  • Workflow: source material -> media encoder -> segmenter -> web server
  • AVAssetWriter - outputs media in fragmented MP4 format.
  • Either source file or capture (live) video to fragmented files via AVAssetWriter.
  • Format structure
    • MP4: file type, movie, media data
    • Fragmented movie (fMP4): file type, media data, movie, media data, movie fragment, media data, movie fragment,…
  • Code example of how to configure AVAssetWriter (~5:30).
  • Lots of detailed examples throughout rest of session.