How to add subtitles to a local video

Keep the video and subtitle together

A subtitle download is a small text file containing words and timing. It does not contain your movie, and downloading it does not change the original video. Keep both files in a folder you can find again. If your browser automatically sends downloads into a separate Downloads folder, move the subtitle beside the video before opening your player.

For a straightforward first attempt, use matching base names: Moonlight.mkv and Moonlight.srt. The video extension stays exactly as it is. Change only the subtitle name if needed. Show file extensions in your file manager so that you do not accidentally produce Moonlight.srt.txt. Matching names help automatic discovery, but you can also select a subtitle explicitly.

Choose the version you want to read

SubLunio offers translated, original and bilingual subtitle variants. The original variant follows the transcribed speech; the translated variant uses your chosen target language. Bilingual output puts both in the same timed cue. Once the task is complete, downloading a different variant does not require another audio upload or a new generation.

For your first playback check, keep only one intended subtitle enabled. If the video already contains an embedded subtitle track, your player may choose that one instead of your new file. Switch to the newly downloaded track and turn off any competing overlay. This prevents two unrelated translations from appearing together and makes timing easier to judge.

Load the subtitle in a desktop player

Open the video in your usual player, then look for its subtitle or track menu. In VLC, the subtitle controls let you load a separate file and choose the active track. Select the file you downloaded rather than a similarly named file from another episode or edition. Menu wording can vary with operating system, language and player version.

Pause on a scene with clear dialogue after the opening titles. Confirm that the spoken line matches the subtitle and that characters display correctly. Then check a scene near the middle and one near the end. A correct first line alone does not prove the whole file is aligned, especially if the recording contains breaks or edits.

You can also open the player from a SubLunio desktop task to preview completed subtitles and adjust their style. Choose desktop burn-in when you need captions rendered into a finished video, or export SRT, VTT or ASS when you only need a subtitle file.

VLC subtitle documentation

Learn about burn-in and embedded tracks

If nothing appears, check selection before regenerating

First check that subtitles are enabled and that the selected track is your new file. Next check the file name, extension and character encoding. An empty scene can be legitimate: a musical introduction or silent transition may have no dialogue to display. Seek to a place where a person is clearly speaking before judging the result.

If a television or older player does not discover the file, try a simple ASCII file name and the SRT variant. Some devices have narrower format and styling support than desktop players. A subtitle that opens correctly on your computer can still need a different format on the destination device; replacing the video itself is usually unnecessary for this diagnosis.

Fix a consistent delay carefully

If every subtitle is early or late by roughly the same amount, a player timing adjustment can help you inspect the result. If the difference grows through the video, or changes suddenly after a scene, investigate whether the subtitle belongs to a different cut. A fixed delay can compensate for an added or removed opening, but cannot realign both sides of an internal cut or inserted break.

SubLunio creates timing from the audio you selected, so use the same original file when checking the result. Do not compare it against a shortened streaming version and assume that the subtitle file is interchangeable. Review names, overlapping speakers and specialist language before relying on the transcript for study, publication or accessibility work.

Create missing subtitles with a preview first

If you do not have a subtitle yet, choose your video on SubLunio, set the target language and generate a preview. There are 110+ subtitle output languages; source speech recognition has its own language menu. Auto is a starting point when the spoken language is unknown. For a dubbed film, select the language and audio track actually present in your file.

The free preview begins with the first subtitle and covers up to 5 continuous minutes, limited by the remaining video duration. Check the dialogue and target wording in the workspace preview. When it suits you, generate the full subtitles for $1 per hour of the complete video, rounded up to a cent. Download SRT, VTT or ASS, then return to the loading steps above. You keep the original video on your device.

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