SRT subtitle file
Standard timed subtitle format: sequence number, timestamp pair (00:00:00,000 → 00:00:00,000 with comma separator), and one or two lines of caption text per block. Supported by YouTube, Vimeo, LinkedIn, most video editors, and accessibility workflows.
VTT subtitle stream
WebVTT format with period timestamp separators (00:00:00.000 → 00:00:00.000). Used by HTML5 video players, streaming services, and accessibility platforms. Unlike SRT, VTT supports <cue> positioning metadata, text styling, and karaoke-mode highlighting.
Burned captions
Permanently embedded caption text rendered directly into the video frame — cannot be toggled off by the viewer. Required for platforms that strip external caption tracks. Font rendering, shadow depth, and vertical position all need QA review after encoding because video compression can degrade caption legibility.