Caption File Formats
While broadcast caption files are embedded in the video, Internet captions are sidecar files that get uploaded after the video is. IP platforms use many caption formats. The hexadecimal SCC Line 21 caption format carries a timed transcript with formatting and positioning. DXFP, SRT, SVB, and VTT captions are human-readable.
| Internet Closed Captions | SCC “608” Line 21 | SRT | DXFP/ TTML/ SMPTE-TT | VTT | SVB/ SUB | ASCII UTF-8 TXT Transcript | Auto Captions | Burned-In Open Captions |
| YouTube | X | X | X | X | X | X | X | X |
| Vimeo *Paid | X | X | X | X | X * | X | ||
| X | X | X | ||||||
| Twitter Periscope | X | X | X | |||||
| X | X | |||||||
| TikTok | X | X |
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