How to Add Subtitles to Video with an SRT File

Add subtitles to video so it works with sound off, the way many people watch short clips. Learn what an SRT file is and how to make good auto subtitles.

Why do social videos need subtitles?

Short videos are often watched in places where people can't or don't want to turn the sound on. If the message lives only in the audio, those viewers can easily keep scrolling. Subtitles fix that, and they do more:

• Sound-off viewing: on public transport, at work, late at night or in a noisy café, the subtitles carry the message.
• Accessibility: deaf and hard-of-hearing viewers rely on subtitles to follow what you say.
• Easier understanding: written text helps viewers who don't speak the video's language natively, or when the speech is fast.
• The key message gets through: the main line comes across even without sound, such as an offer, a date or an address.

What is an SRT file?

SRT (SubRip) is a simple, widely used subtitle format. It is a plain text file you can open in any text editor. It is made of subtitle blocks, called cues, and each cue has three parts: a sequence number, a timecode (when the text appears and disappears, in hours:minutes:seconds,milliseconds format, with an arrow between the two), and the text itself, usually on one or two lines. A blank line separates the cues. Two cues look like this:

1
00:00:00,000 --> 00:00:03,400
Three tips to make your video
easy to follow without sound.

2
00:00:03,600 --> 00:00:07,000
First: show the main point
in the very first second.

Because the format is simple and common, many video editors and video platforms can read it. The file on its own does not change your video: it either goes into the picture or lives next to it as a separate file.

Burned-in subtitles or a separate subtitle file?

Burned-in subtitles become part of the picture: everyone sees them, but they can't be turned off or fixed without re-exporting the video. A separate subtitle file is laid over the video by the player, and viewers can turn it on or off. For short vertical social videos, burning them in is often the safer choice, because every viewer sees them no matter what the app supports.

How to make subtitles easy to read

Good subtitles are the ones viewers barely notice they are reading. A few rules help:

• Short lines: a line should be readable at a glance. A common starting point is 42 characters per line at most; if the text gets too small on a vertical video, go lower.
• Two lines per cue at most: a third line covers even more of the picture and is harder to follow.
• Sensible line breaks: break lines at natural points in the sentence. Don't split a name, a number from its unit, or an article from its noun.
• Accurate timing: text should appear when it is spoken and stay long enough to read comfortably.
• Good contrast: light text with a dark outline or a semi-transparent background bar stays readable on almost any background.
• Safe zone: on full-screen vertical video feeds, the bottom strip and the right edge are often covered by the app's own elements (caption, buttons), so place subtitles above them.

A practical workflow from raw video to finished subtitles

1. Lock the edit. If you trim the start of the video after the subtitles are made, every timecode shifts. Always create subtitles from the final cut.
2. Transcribe the audio. An automatic subtitle tool turns speech into timed text. If you know the video's language, set it, because automatic language detection can miss on mixed-language or quiet speech.
3. Proofread names and brands. People's names, brand names, product names, places, numbers and jargon: always check these by hand. A misspelled brand name in your own video is especially awkward.
4. Adjust the line breaks. Set the characters per line and lines per cue, then check how it looks on the picture.
5. Import or upload. Many video editors can import an SRT file: there you can usually set the font, size and position, then burn the subtitles in. Where the platform or upload screen accepts subtitle files, you can also upload the .srt file separately.
6. Watch it muted, on a phone. That way you see what your viewers see: whether the text stays up long enough and nothing covers it.

Common mistakes

• Unchecked automatic subtitles: machine transcription is a good start, but a person should always review names and numbers at the end.
• Lines that are too long, or three lines at once: viewers can't finish reading before the text disappears.
• Subtitles under the buttons: the app's interface hides half the sentence.
• Subtitles made before the final cut: the timecodes drift and the text no longer matches the speech.
• Garbled accented letters: if strange symbols appear in place of accented characters, the encoding is the problem. Save subtitle files as UTF-8.
• Letting subtitles replace the post text: you still need the caption under the video, because only people already watching the video read the subtitles.

How Lacamio helps

Lacamio takes the transcription and the subtitle file off your plate. Upload the video in the composer or on the Media & subtitles page, and set its language (English, Hungarian, Romanian, German, French, Spanish or Italian) or leave it on auto. Lacamio builds SRT subtitles from the video's audio with word-level timestamps; for longer videos this can take about a minute.

You can then set the characters per line and lines per cue (42 and 2 by default), and the subtitles rebuild without a new transcription. Line breaks follow the character limit you set, not the meaning of the sentence. Download the finished .srt file or copy it. Fixing the words themselves, such as a misheard name, and any awkward line breaks happens in the downloaded file or in your video editor. Lacamio does not burn subtitles into the video and does not attach them to the published post automatically.

From the same transcript you also get three caption suggestions in the video's language, which you can edit, copy or, in the composer, insert into your post with one click. See the details on the AI subtitles feature page. Once the final video is ready, you can schedule it in Lacamio to Facebook and Instagram, and send it to TikTok as a draft that you finish in the TikTok app.

The Free plan includes 1 AI credit a month, enough to process one video, including the SRT and all three captions. Try it on your next video, no card needed: sign up for free.