Reference
Plain-language references for SRT and WebVTT files: how they are structured, how timecodes and text encoding work, and how to translate subtitles without shifting a single timing.
Last updated: 2026-06-11
An honest comparison of free and freemium subtitle translators — file tools, AI transcribers, and browser overlays — by format support, bilingual output, signup, file-size limits, and best use case.
How SubRip (.srt) subtitle files are structured: cue numbers, HH:MM:SS,mmm timecodes, and text blocks.
The WebVTT subtitle format: the WEBVTT header, dot-millisecond timecodes, cue settings, and how it differs from SRT.
SRT and WebVTT compared: timecode punctuation, styling, metadata, browser support, and which to use when.
How subtitle timecodes work, the HH:MM:SS,mmm vs HH:MM:SS.mmm formats, frame rates, and why translation must never change them.
Why subtitles show garbled characters, how UTF-8 and the byte-order mark (BOM) affect .srt/.vtt files, and how to fix encoding.
Step-by-step: translate an .srt subtitle file into another language online while keeping every timecode intact.
Make a dual-language subtitle file with the original and translation stacked under one timecode — for language learning in VLC, mpv, Plex, or any offline player. Free, SRT and VTT.
Translate .ass and .ssa subtitle files online while keeping every override tag, style, and timecode intact — built for anime and immersion-learner files from Kitsunekko. Free, optional bilingual output.
Convert SRT to WebVTT: add the WEBVTT header, change comma milliseconds to dots, and drop optional cue numbers. Plus how to reverse it.
Advanced SubStation Alpha (.ass/.ssa): the [Script Info], [V4+ Styles], and [Events] sections, Dialogue lines, and why anime and karaoke use it.
Subtitle reading-speed limits: ~15-20 characters per second, Netflix 17 CPS adult and 13 kids, 42 chars per line, two lines max, with timing minimums.
Reference table of subtitle reading-speed (CPS) and line-length limits for 30 languages — Netflix caps, characters per line, script, text direction, and text expansion vs English.
Add subtitles to any video: soft sidecar .srt/.vtt files vs hardcoded burn-in, players like VLC and YouTube, the HTML5 track element, and filename rules.
The SRT timecode syntax: HH:MM:SS,mmm with a comma, the --> arrow, cue ordering rules, and common errors like overlaps and negative gaps.