How to check and edit SRT subtitles

Machine-generated subtitles are never 100% right, so proofread before you publish. SRT is plain text; once you know the format and the usual kinds of error, a 10-minute video does not take long.

The SRT format is four lines

Each cue is a number, a timecode, the text, and a blank line:

1
00:00:00,060 --> 00:00:02,900
I want to have a chat with you today.
今天我想和大家聊一聊，

2
00:00:02,900 --> 00:00:05,300
How can a small team
spend very little money?
一个小团队怎样用很少的钱

• The timecode is written hh:mm:ss,mmm --> hh:mm:ss,mmm; note the comma before the milliseconds.
• A bilingual cue is simply a text part with two or more lines.
• There must be one blank line between cues.

What to edit with

• A text editor: for fixing a few typos, macOS TextEdit (saved as plain text) or any code editor is enough.
• An editing app: import the SRT, fix it against the picture, then export. Good if you also want to adjust the styling.
• A dedicated subtitle editor: for many cues or heavy timing changes, for example the open-source Aegisub.

Twinsub only generates files for now and has no built-in editor. That is deliberate: proofreading is left to the tool you already know.

Five kinds of error in machine subtitles

1. Proper nounsNames of people, companies, products and terms. Recognition may write a similar-sounding word, and translation may render it literally. Check these first.
2. Numbers and unitsYears, amounts, percentages. One misheard digit changes the meaning, so check against the video.
3. Homophones and dropped phrasesWhere music covers the voice, half a sentence can be dropped or replaced by a similar-sounding word.
4. Break positionsA cue that ends mid-sentence reads awkwardly. Merge or split cues to fix it.
5. Overlapping or too-short timesTwo cues whose time ranges cross, or a cue shown for under a second so viewers cannot read it. Some editors refuse to import overlaps.

A proofreading order that saves time

1. Search proper nouns firstUse find and replace across the whole file to fix every wrong spelling of the same word at once.
2. Then scan the numbersLook only at cues that contain digits, and check them against the video.
3. Finally watch it throughLoad the subtitles in a player such as IINA, play from the start, and pause only where it reads badly.

A long video does not need to be listened to word by word. With this order, most errors are caught in the first two steps.

Subtitles are for reference; please proofread before publishing. See Terms of Use, section 3.

Updated 2026-10-11. Back to the Twinsub home page