How to Generate SRT or VTT Subtitles for Local Videos on Mac

Create a subtitle file you can load with the video

To generate SRT or VTT subtitles for a local video on Mac, transcribe its audio, review the words, and export a timed subtitle file. Load that file alongside the same video to check it. A readable transcript alone does not establish that subtitles will appear at the right moments.

Alison Workspace is an on-device Mac app requiring macOS 15 or later and Apple silicon, M1 or newer. Its file-transcription workflow produces media-relative timestamps and offers SRT and VTT export. Prepare the required recognition resources first; prepare translation resources too if needed. You can queue several videos, then review and export each record separately. This produces external subtitle files, without burning text into the picture.

Keep the exact video version and its original timeline

First check for a usable subtitle track supplied with the recording. An existing reviewed track may save work. If you need a new one, use a local video you own or have permission to process, with an audio track the app can decode. MP4 and MOV are examples, not guarantees for every encoding. Do not assume that an MKV or a protected download will import successfully.

Keep the version you will actually play or deliver. Removing an introduction or changing the edit after transcription can invalidate its timing. File-transcription times refer to the start of the imported media, including opening silence. A subtitle for a clipped excerpt follows that excerpt's timeline; it will not automatically align with the longer original. Keep the source available for review.

Choose SRT or WebVTT for the destination

SRT contains numbered blocks, start and end times, and subtitle text. Its timecodes use a comma before milliseconds, such as 00:00:12,500. VideoLAN documents SRT support in VLC, making it a useful option for a local playback check. Confirm what your actual editor or receiving platform accepts.

WebVTT uses the .vtt extension, a WEBVTT header, and a period before milliseconds. The W3C specification defines UTF-8 encoding and timed text cues for uses including web video tracks. Choose VTT when the destination requests it.

Renaming a .srt file to .vtt does not convert its contents. Export the intended format. Neither format contains the video itself, and neither makes automatic speech recognition accurate merely by giving the text a timecode.

Transcribe one representative video before adding a queue

Start with a manageable recording to confirm the settings and output.

1. Open Alison Workspace's file-transcription window and add the video, or drag it into the queue.
2. Check the filename and displayed duration.
3. Select the spoken language and prepare the recognition resources.
4. Leave translation off for source-language subtitles, or choose an available target and prepare its resources.
5. Start transcription, then inspect the result and completion status.

The file is read directly; you do not need to play it through speakers. For several videos, add files to the queue and group them around compatible language settings. A run shares settings. The multilingual batch guide explains automatic detection and language-based groups; a queue is not a promise of simultaneous processing or one-click bulk export.

Review words, reading length, and completion

Replay the recording while reviewing its transcript. Correct names, numbers, negative statements, and technical terms. Check the beginning, middle, and end, including passages with overlapping voices or music. If a translated subtitle is needed, review its meaning separately from recognition.

Check whether the result is partial. An allowance limit, cancellation, or failure can leave the ending unprocessed. Resolving the cause and running the file again is different from exporting the same incomplete record again.

Subtitle text also needs time to be read. Long utterances, two-language text, or speaker labels may crowd the screen. Use Alison to correct the text. For cue splitting, retiming, or detailed subtitle presentation, export the file and continue in a dedicated subtitle editor.

Select the language content and export each record

Finish editing, then open that transcript's Export menu. Under Export Content, choose source text, translation, or bilingual content, then select SRT Subtitle File or VTT Subtitle File. SRT and VTT retain timing even when document timestamps are turned off.

Bilingual export places the source and available translation within the same cue. It does not create two independently selectable language tracks. Translation-only export skips segments that have no translated text; check for missing passages before handing it over. If a record has no translation at all, its export resolves to source text.

Save each video's subtitle separately, with an identifiable name such as lesson-01.srt beside lesson-01.mp4. Check that the extension is correct, rather than .srt.txt. Repeat from each record's menu. Choose the export folder deliberately: a synced or shared folder can distribute text even though recognition ran locally.

Load the SRT in VLC on Mac and watch three passages

Use the exported SRT for this local check. The following menu names are from VLC's English Mac interface.

1. Open the same video version in VLC.
2. Choose Subtitles → Add Subtitle File… and select the exported .srt file.
3. Check the Subtitles Track submenu and select the intended track if necessary.
4. Play a passage near the beginning, another in the middle, and one near the end.

Check when each subtitle appears and disappears, whether it matches the speech, and whether both languages remain readable. Manual loading confirms which file you are checking instead of relying on automatic filename matching. Test VTT in the player, editor, or web destination that will actually use it. Exporting a format does not establish every application's support for it.

Troubleshoot absent subtitles and garbled characters

If nothing appears, confirm that a subtitle track is selected and that playback has reached a cue's time. Open a copy of the subtitle in a plain-text editor: it should contain timing blocks and actual words, not an empty file or a renamed document. Check the extension and the destination's supported formats.

If only some passages disappear, compare the source transcript, translation coverage, completion status, and exported file. A translation-only export can have gaps where translation was unavailable.

Alison writes these exports as UTF-8. WebVTT requires UTF-8; SRT readers can differ in encoding handling. For garbled characters, check the player's subtitle encoding and whether another editor changed the file's encoding. Keep a clean export. A font lacking the needed characters can also produce missing-glyph boxes.

Separate a constant timing offset from growing drift

When every subtitle is early or late by a similar amount, first check that video and subtitles came from the same edit. A player's subtitle-delay control can help diagnose a constant offset; it does not prove that the saved subtitle file has been corrected.

If the difference grows, or changes suddenly after a cut, compare the source version and playback settings. A single delay cannot repair different edit points or every timing error. Use a subtitle editor to inspect the cues, or regenerate from the final video when appropriate.

Before delivery, recheck the saved subtitle with the final media. Preserve the original video and an unedited export. A useful finished result has reviewed wording, readable cues, and timing verified in its destination. Check all three before sharing the file.