Captions / delivery
SRT caption validator and shifter
Check an SRT for malformed indexes and timestamps, then apply a positive or negative timing offset without uploading caption text.
Runs locallyNo sign-inFree
Browser-local toolVC / SRT
Production notes
What this result means
Validate SRT cue structure and timing, shift every caption locally, preview the result, and download a corrected copy. Results are intended for planning and convenience; confirm critical values in your editing, encoding, or delivery system.
Useful for
- Fixing a consistent caption sync offset
- Checking a subtitle handoff before delivery
- Detecting overlaps and non-sequential cue numbers
Assumptions
- Timestamps use HH:MM:SS,mmm and cues are separated by blank lines.
- Negative shifted times are not silently clamped and are reported as errors.
- Text, line breaks, and optional cue-setting text after the end time are preserved.
Limits & checks
- The tool validates structure and timing, not spelling, reading speed, line length, or accessibility quality.
- Complex non-SRT subtitle formats are not converted.
- Always review the exported captions against the final picture and delivery specification.
FAQ
Before the final export
Does a positive shift make captions later?
Yes. +1000 ms adds one second to every start and end time.
Are overlapping cues always invalid?
Not universally, so overlaps are warnings rather than blocking errors.
Does validation change my original file?
No. The original is untouched; download creates a new local file.