Subtitles & Closed Captions: SRT, VTT & ASS
Synchronizing text transcriptions with video streams and streaming platforms.
Your files are processed entirely in your web browser using HTML5 Canvas and WebAssembly. Zero data ever leaves your device.
Skip upload and download queues. Conversions happen locally at full machine hardware speed without server limits.
Compliant with official ISO, W3C, and IETF specifications to guarantee output compatibility across modern operating systems.
Format Comparison & Technical Specifications
| Output Format | MIME Type | Specification | Type |
|---|---|---|---|
| SRT SubRip Text | text/plain | SUBRIP-SPEC | SubRip Timed Caption File |
| VTT WebVTT Caption | text/vtt | W3C-WEBVTT | Web Video Text Tracks |
| ASS Advanced SubStation Alpha | text/x-ssa | ASS-SPECS | Styled SSA Subtitle Script |
| SUB MicroDVD Subtitle | text/plain | SUBRIP-SPEC | MicroDVD Frame Subtitle |
| TXT Plain Text Transcript | text/plain | RFC-4180-CSV | Unformatted Subtitle Transcript |
Technical Specifications & Codec Breakdown
SRT vs. WebVTT: The Web Video Standard
SRT is the classic, simple subtitle format supported by almost every media player. WebVTT is the modern W3C web standard: it supports styling (colors, font sizes, positioning), making it the required format for HTML5 video players and streaming platforms.
Timestamp Drift & Frame Rate Mismatches
If video audio and captions slowly drift out of sync over a 2-hour movie, it is usually caused by a frame rate mismatch (e.g., 23.976 fps film vs. 25 fps PAL video). Converting subtitle timecodes ensures captions match the exact audio cues.
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