My friend is trying to encode a Disney show (The Replacements) into DVD format to create an unofficial DVD.

We ripped the episodes from iTunes and decrypted them using ViWizard M4V Converter. (Yes, the show is on Disney+, but it has Season 1 only, but iTunes has the episodes in 480p which is fine). The videos play fine, and macOS (QuickTime and Finder Quick Look) displays the captions correctly. However, DVD Styler does not recognize the captions, and we have not been able to find a DVD authoring workflow that preserves them.

According to ffmpeg, the captions are EIA-608 (Line 21 closed captions) embedded in the M4V. This creates several issues:
  • Converting the captions to SRT or WebVTT loses positional data, since those formats do not support it.
  • When converting to SRT via ffmpeg, captions appear in the top-left corner and sometimes merge or distort lines.
  • ASS subtitles would preserve positioning, but DVD Styler does not support them.
  • VLC does not display the captions when playing the original MP4/M4V.
  • ViWizard can export to VOB or MPEG-2, but doing so breaks or removes the captions.
  • TunesKit’s subtitle extraction outputs SRT but strips or damages the captions.
  • CCExtractor also fails to properly extract them.
  • Other iTunes shows (e.g., Yin Yang Yo!) do not seem to have this problem.

Our goal is simply to author a DVD while preserving the existing Line 21 closed captions and their positional data, without converting them into a format that breaks layout or timing.

Is there a way to pass through or re-encode embedded EIA-608 captions from an M4V into a DVD-compliant stream correctly? Is there a tool or workflow that supports this use case?