Shift subtitle timing
Type how far the subtitles are off and move every line earlier or later in one step. Load the video to check the result before you download.
workbench · no file open
.srt .vtt .ass .ssa .sbv
Drop a subtitle file here
Drop the video too to preview the lines over it and to set each start and end by its sound. Nothing is uploaded. No subtitle yet? Make one from the audio with transcribe.tools.
Formats it reads and writes
| Format | Timecode | Kept when saved here |
|---|---|---|
| SRT.srt | 00:01:23,450 | Italic, bold, underline, font tags |
| WebVTT.vtt | 00:01:23.450 | Italic, bold, underline |
| ASS.ass .ssa | 0:01:23.45 | Styles, actors, {\an8} and {\pos} when the file was ASS |
| SBV.sbv | 0:01:23.450 | Text only |
Reading speed and timing limits
The presets of the checker: Netflix English. Every number can be changed.
| Limit | Adult | Children’s |
|---|---|---|
| Characters per line | 42 | 42 |
| Lines per subtitle | 2 | 2 |
| Reading speed, CPS | 20 | 17 |
| Shortest on screen | 833 ms | 833 ms |
| Longest on screen | 7 s | 7 s |
| Gap between lines (2 frames at 24 fps) | 83 ms | 83 ms |
Source: Netflix Partner Help Center, English (USA) Timed Text Style Guide; Netflix Partner Help Center, Timed Text Style Guide: General Requirements; Netflix Partner Help Center, Timed Text Style Guide: Subtitle Timing Guidelines, opened .
Check a file against these limitsHow to use the shift timing
- 00:01
Open the subtitle
Drop an SRT, VTT, ASS or SBV file, and the video if you have it. Both stay on your device.
- 00:02
Find the offset
Pause where a line is heard, pick that line, and use the difference between the two times.
- 00:03
Shift and save
Move the lines earlier or later, check over the video, fine-tune a line’s edges on the waveform, and download.
How do I know how much to shift?
Load the video, play to a line of dialogue you can hear clearly, and pause at the moment it starts. Select that line in the list: the panel shows the line’s start and the video time side by side, and Use the difference fills the offset for you. If the words appear before you hear them, the subtitles are early and need a positive shift; if they appear late, a negative one.
Earlier or later: which sign do I use?
A positive offset delays the subtitles (they appear later); a negative offset advances them (they appear sooner). The buttons say Earlier and Later so you do not have to think about signs. An offset can be as small as one millisecond or as large as several minutes, written as seconds (1.5), minutes and seconds (1:30.2) or a full timecode.
What if only part of the film is out of sync?
That happens when a cut or an ad break differs between your copy and the one the subtitles were made for. Fill in “Only lines from” with the time where the drift starts, and only those lines move. Repeat for each break if there are several.
What if the delay keeps growing through the film?
A shift moves every line by the same amount, so it cannot fix a delay that grows. A growing delay comes from a different frame rate or a different edit of the film. Use the two-point resync, which stretches the timing between two lines you check by ear, or the frame-rate change if you know both rates.
Questions
What happens to lines that move before 0:00?
A line that would start before the beginning starts at 0:00 instead; a line that would end before it is removed, and the panel tells you how many were removed. Undo brings them back.
Can I shift by frames?
Type the time in seconds: one frame is 1/24 of a second at 24 fps (about 42 ms) and 1/25 at 25 fps (40 ms). Shifting in milliseconds is as precise as SRT and VTT allow.
Does shifting change the format?
No. The file is downloaded in the same format unless you pick another one. ASS files keep their styles.
Can I shift a VTT or ASS file, not only SRT?
Yes. Shifting works the same on SRT, VTT, ASS and SBV.
My player has a subtitle delay setting. Why change the file?
A player setting is lost on the next device or the next episode. A corrected file plays in sync everywhere, on a TV, a phone or a website.
More subtitle tools
- Subtitle editorEdit lines over your video, then save as SRT, VTT, ASS or SBV.
- SRT to VTTWebVTT for HTML5 players, with header and timestamps rewritten.
- Fix syncTwo-point resync and frame-rate change for drifting subtitles.
- ASS to SRTPlain SRT from ASS or SSA, with italics and line breaks kept.
- Merge and splitJoin two parts, combine two languages, or cut a file in two.
- Line length and CPSCharacters per line, reading speed and timing against your limits.
Sources
- WebVTT: The Web Video Text Tracks Format
A WebVTT file starts with the string WEBVTT; timestamps use a dot and three digits for milliseconds, and hours are optional when zero.
W3C. Opened on .
Style limits differ between broadcasters, languages and clients; the presets are one published guide, and every limit can be changed. Your files never leave your browser.