Subtitle Timeline Aligner
Fix offset, correct drift, and convert frame rates for SRT & VTT subtitle files
Input Subtitle
Alignment Mode
Adds a fixed number of milliseconds to every start and end timestamp. Use a positive value to push subtitles later, negative to pull them earlier.
When to Use Subtitle Timeline Aligner
Fixed Offset Sync
Subtitles consistently appear 2 seconds too early or late? Use Fixed Offset to shift the entire timeline by a precise millisecond amount in one click.
PAL / NTSC Speedup
Subtitles made for a 23.976fps print drift when played on 25fps PAL video. Use Frame Rate mode to scale timestamps by the exact fps ratio.
Drift Correction
Subtitles start in sync but are off by 5+ seconds at the end? Two-Point sync calculates the linear stretch factor to correct gradual drift across the whole file.
Different Video Cuts
Theatrical vs. director's cut, or extended edition with extra scenes? Use Single Point or Two-Point sync to align subtitles to the version you have.
Re-timing Translations
When a translated subtitle was timed to a different language master, re-time it to match your video's actual timestamps using reference cues you can verify.
Streaming Rip Sync
Subtitles downloaded from subtitle sites often have offsets matching a specific rip or stream. Quickly re-sync them to your local video file without installing software.
Frequently Asked Questions
What is subtitle drift and how do I fix it?
Drift occurs when subtitles start in sync but gradually fall behind or run ahead. Use Two-Point Sync โ identify one cue near the start and one near the end, enter both original and correct times, and the tool calculates the linear correction needed.
What is the difference between Fixed Offset and Single Point?
Fixed Offset adds a set number of milliseconds directly. Single Point lets you enter what a timestamp should be โ the tool computes the offset for you. Use Single Point when you know the correct time of a specific subtitle but don't want to do the subtraction manually.
When should I use Two-Point sync?
Use Two-Point when subtitles drift โ in sync at the beginning but off by several seconds at the end. Find one cue near the start and one near the end that you can verify the correct time for, enter both pairs, and the tool corrects the whole file linearly.
How does frame rate conversion work?
When a subtitle is made for a 25fps video but you're watching at 23.976fps (or vice versa), all timestamps are off by the fps ratio. Frame Rate mode multiplies every timestamp by origFPS / newFPS, correcting PAL speedup and telecine-related timing issues.
Is my file uploaded to a server?
No. All processing happens entirely in your browser using JavaScript. Your subtitle content is never sent to any server, ensuring complete privacy.
Which subtitle formats are supported?
SRT and WebVTT are both supported. The tool auto-detects the format, applies the transformation, and outputs in the same format with all text and structure preserved.
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