Subtitle generator
Drop in a video and get SRT or VTT back. These are automatic captions grouped by the same readability rules broadcasters use, not text chopped wherever the model happened to pause — and it all happens on your Mac, so an unreleased cut stays an unreleased cut.
macOS 14.4 or later · Apple silicon · $29 once, not per month · 7-day trial
How it works
Three steps, none of which involve an upload, an account or a queue.
Drag in an MP4 or MOV, or point Kekoso at the folder your editor exports to. The audio track inside the file is what gets read; there is no separate extraction step and no upload.
Recognition produces words with timings, and those words are grouped into caption cues by readability rules rather than chopped wherever the model paused. Line length, line count, duration and reading speed are all decided here.
Take the subtitle file into Premiere, Final Cut, DaVinci, VLC or a YouTube upload. TXT is there too, when you want the words without the timecodes.
What the subtitle generator does
Every subtitle generator claims accuracy. Almost none of them say what rules the cues are built to, which is the part a viewer actually feels.
Kekoso follows the Netflix Timed Text Style Guide: at most 42 characters per line, at most two lines per cue, each cue on screen between 0.833 and 7 seconds, and a reading speed under 17 characters per second. That is the difference between subtitles a viewer can read and text that merely appears at the right moment.
A line never splits in the middle of a word, and no word is dropped or rewritten to make a cue fit. Where speech is genuinely too fast to fit the reading-speed limit, the cue keeps every word rather than quietly trimming what you said — verbatim wins over cosmetics.
SubRip with numbered blocks and HH:MM:SS,mmm timecodes; WebVTT with its signature line, HH:MM:SS.mmm timing, and the escaping that format needs so an ampersand or a bracket in your speech does not break the file.
Speech models invent text on pauses — Whisper is famous for captioning long silences with sign-off lines that were never spoken. Kekoso drops segments with no audio behind them, which is the difference between automatic captions you can ship and ones you have to proofread for phantom lines.
A watched folder turns every new export into a subtitle file by itself. Ten videos from a shoot become ten SRTs while you do something else, with no queue and no per-minute charge.
Parakeet covers English and 24 other European languages quickly, Whisper reaches the long tail, SenseVoice handles Chinese, Cantonese, Japanese and Korean. Subtitles are generated in the language that was spoken.
When a file beats burnt-in captions
Auto captions that a feed draws over your video and a subtitle file you can hand to something else are answers to different questions. Here is which is which, including the case where the honest answer is that this page is not for you.
Used as a YouTube subtitle generator, this produces a file you upload rather than captions the platform guesses at. YouTube takes an uploaded subtitle track and lists SubRip (.srt) and WebVTT (.vtt) among its supported formats — with the note that SRT carries no style information and VTT supports positioning with limited styling. An uploaded track is indexable, switchable and editable later, which auto-captions burnt into the picture are not.
Final Cut, Premiere, DaVinci and VLC all take a sidecar file directly. So does a media archive that has to stay searchable: the words live in a text file next to the video rather than inside its pixels.
A subtitle file is a text file. Names, terms and mishearings are fixed in a text editor in seconds, and the corrected file replaces the old one. Captions rendered into frames are fixed by re-exporting the video.
These platforms generate captions themselves inside the app and draw them over the picture, and uploading your own subtitle file is not part of that flow. If the video is only ever going to a vertical feed, the built-in captions are free and already there. A subtitle AI earns its place when the same footage also goes somewhere that expects a file.
Where the footage goes
To generate subtitles automatically, an online tool needs your video first. That means an unreleased edit, a client review cut, an internal briefing or a course you have not launched yet, sitting on someone else’s disk under terms you skimmed.
Kekoso reads the file where it lies. The pipeline makes no network calls, nothing is copied, and the subtitle file lands next to the video. Pull the ethernet cable and generate captions anyway — the output is the same, because there was never a server in the loop.
How to verify that yourselfWhat it does not do
Whisper reports word-level times and gives the tightest cues. Parakeet reports token times, which is close. SenseVoice reports no timings at all, so they are estimated by spreading words evenly across the window — subtitles from SenseVoice are noticeably coarser, and that is the model’s limit rather than a setting.
You get a sidecar file — SRT or VTT — not a re-encoded video with text baked into the frames. As a subtitle creator this is the whole output: a file, not a render. Every editor and every player takes the file directly, and burning in is a job for the editor, where you also control the font and the position.
Subtitles come out in the language that was spoken. Translating them into another language is a separate step with separate tools, and pretending otherwise would mean shipping machine translation nobody reviewed.
A video with several people on a single microphone produces cues without names in front of them. Calls recorded on the Mac are the exception — microphone and system audio are captured separately and stay labelled.
macOS 14.4 or later · Apple silicon. Recognition leans on the Neural Engine, which Intel Macs do not have.
Questions
Pricing
Four jobs that usually arrive as four subscriptions, running on hardware you already paid for.
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macOS 14.4 or later · Apple silicon