How to Generate Timed SRT and WebVTT Subtitles From Audio Online
A subtitle file is a plain text list of numbered lines, each with a start time, an end time and some words. That is the whole format, and both common versions of it are readable in a text editor. SRT is the older and more widely accepted, using a comma before milliseconds. VTT is the web standard, using a period instead and beginning with a WEBVTT header. Video platforms, players and editors all read one or both. Generating them means transcribing with the timing kept. The model here produces text in chunks with start and end times attached, and those chunks are written into whichever format you choose. Because the timing comes from the recognition rather than from splitting a finished transcript, the lines land where the speech actually falls. The timings are close rather than exact. Boundaries are placed where the model thinks a segment starts and ends, which on natural speech with pauses and hesitations is a judgement rather than a measurement. Expect to nudge some lines. Anything published for accessibility should be checked by a person regardless, because automatic captions fail hardest on exactly the words that carry the most meaning: names, places and technical terms. The privacy point matters here as much as it does for transcription. Uploading a video to a captioning service means giving away the content before it is published, which for anything embargoed is not an option. This runs on your machine, so the subtitles exist before anything is shared. A practical note on line length. Automatic segmentation sometimes produces lines longer than comfortable to read at speed. Subtitles are conventionally kept to about forty characters a line and two lines at once, and splitting the long ones afterwards in a text editor is quick, since the format is plain text.
How to Use the Audio369 Online Subtitle Generator (Step-by-Step)
For a video, extract the audio first with the Extract Audio from Video tool, which handles MP4, MOV, MKV and WebM.
The same two Whisper sizes as the transcription tool. Naming the spoken language is one less thing for the model to infer.
The result is shown as segments with their times, which is where obvious mistiming and misheard names are easiest to spot.
SRT for most video platforms and players, VTT for HTML5 video and the web. Both are plain text and easy to correct afterwards.
Technical Architecture & Audio Engine Specifications
SRT or VTT
| SRT | VTT | |
|---|---|---|
| Time separator | ✓ Comma before milliseconds | Period before milliseconds |
| Header | ✓ None | WEBVTT on the first line |
| Best supported by | ✓ YouTube, players, editing software | HTML5 video and the web |
| Styling | ✓ None | Positioning and basic styling supported |
| If unsure | ✓ Choose this one | Choose this for your own web player |
Who Uses Audio369 Subtitle Generator? (Practical Creative Workflows)
Captions for a video
Most viewers on social platforms watch without sound, so captions are not an accessibility extra there, they are how the video gets watched.
Accessibility compliance
Captions are required for a great deal of published video, and generating a draft is the slow part that this removes.
Subtitles for a talk or lecture
Recorded teaching is far more useful with timed text, both for searching and for following along in a second language.
Content under embargo
Material that cannot be uploaded before release can still be captioned, because nothing here leaves the browser.
A timed index of a long recording
Even where you do not need subtitles, an SRT is a searchable index of exactly when everything was said.
Frequently Asked Questions (FAQ)
Should I use SRT or VTT? +
SRT unless you know otherwise; it is accepted almost everywhere. VTT is the web standard and the right choice for an HTML5 player, and it supports positioning that SRT does not.
How accurate are the timings? +
Close, not exact. The boundaries come from where the model thinks segments begin and end, which is a judgement on natural speech. Expect to adjust some lines, particularly around pauses.
Can I generate subtitles directly from a video file? +
Extract the audio first with the Extract Audio from Video tool, then bring that here. The recognition needs audio rather than a video container.
Are the subtitles in the same language as the speech? +
Yes, this transcribes. If you want English subtitles for speech in another language, use the Audio Translation tool, which uses the model's translate task.
Why are some of my lines too long to read? +
Automatic segmentation follows the speech rather than reading speed. Convention is around forty characters per line and two lines at a time, and since the file is plain text, splitting long cues afterwards takes a moment.
What is the difference between SRT and WebVTT subtitle formats? +
SRT (SubRip) uses comma millisecond separators and is standard for desktop media players and YouTube uploads. WebVTT uses period separators and supports modern HTML5 web video players.
How accurately does Whisper synchronize word-level timestamp boundaries? +
The transformer model aligns acoustic attention weights with phonetic onsets, generating subtitle blocks with millisecond-precise start and end times that match spoken cadences naturally.
Can I upload generated SRT subtitles directly to YouTube and TikTok? +
Yes. The exported SRT files conform strictly to standard SubRip syntax, making them immediately compatible with YouTube Studio, Premiere Pro, DaVinci Resolve, and Final Cut Pro.