Most SRT fixes are small: a misspelled name, a line that stays on screen too briefly, or a whole file that runs half a second late. The right tool depends on the fix. A plain text editor is enough for wording. Timing and sync problems are faster in a subtitle editor that shows the cues against the video.
This guide covers both, in the order most edits happen.
Before you edit
- Work on a copy. Keep the original file so you can compare or start again.
- Check the encoding. Open the file and look at accented letters. If they look garbled, re-open it with the correct encoding and save it as UTF-8 before changing anything else.
- Know what each cue looks like. Every cue has a number, a timecode line such as
00:01:12,400 --> 00:01:15,000, one or two lines of text, and a blank line after it. Edits must keep that structure.
Fix text in a plain text editor
For wording, any plain text editor works: Notepad, TextEdit in plain text mode, or a code editor.
- Typos and names: use find and replace for names and terms that appear many times, so every cue gets the same spelling.
- Line breaks: a cue can hold one or two lines. Break long lines at a natural pause, not in the middle of a name.
- Removing a cue: delete its number, timecode, text and the blank line that follows. The remaining numbers then skip one. Many players tolerate the gap, but renumbering keeps the file clean, and subtitle editors do it automatically.
Avoid word processors. They can save curly quotes, hidden formatting or the wrong file type.
Shift the timing of the whole file
When every subtitle is early or late by the same amount, shift the whole file instead of editing each cue.
- To test the offset, play the video in VLC with the subtitles loaded and press G or H to move the subtitles earlier or later in small steps. Note the delay that makes the lines match the speech. This changes playback only, not the file.
- To apply it, use a subtitle editor's shift or offset command. Free desktop tools such as Subtitle Edit and Aegisub can shift all cues, or only the cues after a chosen point, by an exact amount.
If the subtitles start in sync and drift further out as the video plays, a single shift will not fix it. That pattern usually means the file was made for a different frame rate or a different cut of the video.
Fix individual cues
Some problems belong to one cue at a time:
- Too short to read: extend the end time, or merge the cue with its neighbor.
- Too long on screen: shorten the end time so the subtitle leaves when the speaker stops.
- Overlaps: make sure each cue ends before the next one starts. Overlapping cues can flicker or stack on screen.
- Too much text: split a long cue into two, and divide the time between them so each part is readable.
A subtitle editor shows a waveform or the video next to the cue list, which makes these edits much faster than typing timecodes by hand.
Check reading speed and line length
After text and timing edits, check that viewers can actually read each cue. Many platforms set limits on characters per line and characters per second. Netflix's English style guide, for example, allows 42 characters per line. Cues that break these limits need shorter wording or more time.
Test the edited file
Load the saved file with the video and watch at normal speed. Check the start, a fast dialogue scene and the end. Then open the file in a text editor one last time to confirm the extension is still .srt and the structure is intact.
Editing SRT files in Aivently
Aivently's editor opens after you translate a subtitle file or transcribe audio or video. The source and the result appear side by side, and you can edit text and timing, use find and replace, and preview each cue against the video or audio. The editor warns you about overlaps, gaps, characters per line and reading speed, saves automatically and keeps versions, so you can return to an earlier state.
When the file is ready, export SRT, VTT, ASS, TXT or JSON. Translations keep cue identity and timing from the source, so most edits are about wording, not repairing structure. The file is measured first, so you see the exact credit total before a job runs.
Translate an SRT file and edit it side by side or transcribe audio or video into editable subtitles.