Frequently asked questions

Choose a local video, check the audio track, then select the spoken language and subtitle language. Start a free preview to review the result. Sign in when you’re ready to generate the full subtitles.

You can watch a continuous 5-minute subtitle preview starting at the first subtitle, or the remaining video if it is shorter. No payment is needed. The preview is viewed in the player; downloadable subtitle files require full generation.

Guests can try 1 free preview. After verifying your email and signing in, the limit is 10 in total across your account or the same browser, including the guest preview. This allowance does not reset daily. Cancelling or deleting a task does not restore a preview.

It depends on the video length, your device’s audio extraction speed, your upload connection and the processing queue. The task shows its current stage. There is no fixed completion time; longer videos and busy periods can take longer.

SubLunio supports common containers including MP4, MOV, MKV, AVI, WebM, WMV, FLV, M4V, TS, MPG, 3GP and RMVB. The audio codec inside the file also matters. The file check will tell you if your video can be processed; the extension alone does not guarantee compatibility.

Yes. The browser reads video in chunks without loading the entire file into memory. Duration limits are 3 hours for guests and 8 hours when signed in. Available device storage, supported codecs and extracted audio size still apply.

Choose the track containing the dialogue you want subtitled, especially for videos with multiple languages or commentary tracks. Listen to the selected track before starting. Subtitles are generated from that track, so choosing the wrong one can produce the wrong language or content.

Browser playback support differs from subtitle generation support. If the original video cannot play, the player may offer a locally prepared compatible preview. You can also choose to display only subtitles and continue working without video playback.

Keep the tab open during local audio extraction and upload. Once processing is on the server, you can return to the task to check progress. If interrupted, use the available resume or retry action; you may need to select the original file again. Avoid clearing browser storage before resuming.

Burn-in needs both the completed subtitles and the local video. SubLunio does not store your original video. If you open a task from My subtitles, move the file or change computers, select the matching original video so the desktop app can verify it. Use the same video version to keep timing aligned; you do not need to generate the completed subtitles again.

Burn-in re-encodes the video, so it takes longer than saving a subtitle file. Processing time depends on video length, resolution, output quality and your computer. Keep enough free disk space for the new video. Subtitle generation, playback, burn-in and embedding have different compatibility requirements; review the file check and any listed track or picture changes before exporting.

Choose from 118 subtitle target languages, including English, Chinese, Japanese, Spanish, Arabic, Hindi and Indonesian.

Auto detects supported speech before generating subtitles. If you know the main spoken language, select it explicitly, especially for short dialogue, accents or background noise. The spoken language and subtitle output language are separate choices.

Accuracy varies with audio clarity, accents, overlapping speech and specialist vocabulary. Use the free preview to check your video, and review names, numbers, timing and meaning before sharing. AI output may need corrections; a supported language is not a guarantee of perfect results.

Yes. A completed task can offer original, translated and bilingual versions when translation is applicable. Bilingual subtitles show both languages, with an order you can choose. When the source and target are effectively the same language, duplicate bilingual lines are collapsed.

Use SRT for broad player and editor compatibility, VTT for web players, or ASS for players that support richer subtitle styling. Full tasks support these formats. You can download another format from the same completed task without generating the subtitles again.

The free preview lets you inspect subtitles in the player before paying. Complete subtitle files are available after full generation finishes. If you cancel a paid task, any retained partial subtitles can be downloaded when the task shows that option. Payment alone does not make a running task ready to download; check its status first.

Yes. The subtitle workspace lets you correct subtitle text and search or replace text. Save your changes, then download the updated subtitle file. Check important names against the original audio; editing the original text does not automatically retranslate it.

Export separate SRT, VTT or ASS subtitle files for playback or further editing, or burn subtitles directly into your video in the desktop app. Preview and adjust the style before burn-in. Burned-in text becomes part of the picture and cannot be switched off. Video output saves a new file by default, with the option to replace the original video where supported. To keep subtitles inside the video file and allow them to be switched on or off, use “Embed subtitle track” for supported video formats.

Burn-in is available in the desktop app. After full subtitle generation finishes, choose Burn in on the completed task or in My subtitles. Select the original video if prompted, preview and adjust the subtitles, choose where to save the video, then start burn-in. The website’s free subtitle preview cannot be exported as a burned-in video.

Burn-in makes the text part of the picture, preserving its appearance wherever the video plays; it cannot be turned off. Embedding adds a subtitle track that can be switched on or off in compatible players, while copying video and audio without re-encoding. Embedding is available only for supported files, and subtitle appearance depends on the subtitle format and player.

Yes. Before burn-in, preview and adjust the font, size, color, opacity, outline and position. Choose the available original, translated or bilingual subtitles and the bilingual line order. Check long lines, font coverage and margins in the preview, especially for vertical video. Burn-in makes the selected text and style permanent in the output video.

Yes. In the desktop queue, select completed tasks and choose “Write subtitles to video” above the list. Apply one subtitle style to the batch or keep each task’s saved style, then review the file list and save location before starting. If some files cannot use the selected settings, resolve the listed issues or export them in separate batches.

A new video file is saved by default. Where supported, you can choose to replace the original; the app creates and verifies the new video before replacing it. Burned-in text cannot be hidden or removed by changing subtitle settings. Keep the original video and editable subtitles so you can make another version later; burning an already captioned video again may add a second layer of text.

Check that your player has subtitles enabled and is using the correct file and video version. Try SRT if your player does not support the selected format. For a consistent timing offset, adjust subtitle delay in your player or use an external subtitle editor, then review the beginning and end of the video.

Full subtitle generation costs USD $1 per video hour, based on the entire measured video duration and rounded up to the nearest cent. For example, a 90-minute video costs $1.50. Review the estimated cost and any amount reserved from your balance before starting.

No. The preview is free to watch, but full generation is charged for the entire video, including the previewed portion. The preview helps you check the result before deciding to pay; it is not a discount on the full video duration.

No subscription is required. You can pay for one video or add USD credit to your account. The minimum card payment is $1.00; any amount left after the task remains reusable balance. Paid credit has no scheduled expiry.

Generating subtitles in a new target language is a separate generation and charge. Downloading SRT, VTT or ASS, or choosing available original, translated and bilingual versions of the same completed task, does not create a new generation charge.

Burning in or embedding completed subtitles runs on your computer and does not use additional subtitle-generation credit. Changing the style or exporting the same completed subtitles again does not create a generation charge. Generating subtitles for the first time or in a new target language is still charged under the normal pricing rules.

A recoverable failure can retain its charge during the retry period; automatic refunds for permanent failures or an expired retry period keep their existing rules. If you actively cancel a running or failed task, you pay only for audio segments successfully transcribed and saved. Overlapping ranges count once; failed or unprocessed ranges and the earlier free preview are excluded. The combined duration is charged at USD $1 per hour, rounded up to the nearest cent once, not per segment. The remaining charge or reservation returns to your balance, and saved source subtitles and completed translations are retained. A refund to your card is a separate process.

Contact support with your account email, payment ID and reason. Refund requests for unused credit due to a change of mind are reviewed individually and are not guaranteed. Service failures, incorrect charges and mandatory consumer rights are handled under the refund terms that apply to your payment.

No. Your browser or desktop app extracts compressed audio locally, and only that audio is uploaded for server-side processing. This also applies to previews: audio may be extracted and uploaded for the whole video. Subtitle generation is not entirely offline.

No. The desktop app previews and writes subtitles into the video locally, and saves the result on your computer. It does not upload the original or output video for burn-in. Signing in and fetching completed subtitles may still require an internet connection, and generating subtitles uses the online audio-processing service.

Server audio is removed after full transcription or normally expires after 24 hours. Starting full generation or awaiting payment confirmation can extend the deadline. In the browser, cached audio is normally reusable for 7 days, but storage pressure can remove it sooner. Expired browser cache is removed at the next cleanup, and you can clear it in Settings. Temporary audio in the desktop app follows its audio-cleanup setting.

Sign in and open My subtitles to find tasks associated with your account. Completed tasks let you reopen available subtitles and download them again. To play the video alongside them, you may need to select the original local file, because SubLunio does not store your video.

Yes. Settings includes account data export and deletion, with identity verification. Download anything you want to keep first. Account deletion removes access to tasks and forfeits remaining credit on confirmation; resolve any refund request beforehand. Required financial and legal records follow the retention periods in the Privacy Policy.