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Subtitle guides

The rules behind every check in Subtidy, with the published limits, worked examples and free calculators.

Most subtitle files fail QC for the same four reasons: lines that are too long, text that reads too fast, cues that overlap, and timing that drifts after a frame rate change. Each guide explains one of them, cites the Netflix and BBC guidelines where they apply, and ends with a way to fix the problem in your own file.

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Subtidy checks and fixes SRT, WebVTT and ASS subtitles in your browser. Free for one file at a time, and nothing is uploaded.