Subtitle generator from a YouTube video link

What a link gets you, and what it does not

A subtitle generator from a YouTube link can mean two different jobs. One is a text file of subtitles for a video, which you then upload back to YouTube or a player. The other is a short, captioned, vertical clip cut out of a long video. KeyMo does the second. It reads the speech, finds the strongest moments, and returns clips with the words already on screen.

The three steps

1. Paste the link. On a paid plan, paste the YouTube URL into KeyMo and confirm that you own the video or have permission to use it. The import fetches up to 1080p, so the source quality is capped there.
2. Choose a clip length and wait. Auto picks between 15 and 90 seconds; Short is 20 to 40, Medium 40 to 60 and Long 60 to 90. KeyMo transcribes the video, picks moments, and scores each clip out of 10 with a one-line reason. Only clips scoring 7 or higher are kept.
3. Pick a caption style and export. Choose one of 12 styles or none. Captions run word by word. Each clip is 9:16, 1080x1920, 30 fps, with no watermark, and you can download them all in one ZIP.

To fix a word or change a style on one clip, open it in the chat editor and describe the change. The wider walkthrough is in how to clip a YouTube video.

A worked example

Say you have a 60-minute interview on YouTube. It sits within the 5-minute to 3-hour range KeyMo accepts. On Starter, which includes 300 source minutes a month, that one video uses 60 of them, so about five episodes of that length fit in the month. Pro includes 900 source minutes, or about fifteen. A single source video can be up to 180 minutes.

KeyMo's built-in target for a video up to 60 minutes is 8 to 12 clips. That is a design target, not a measured result: a weak episode returns fewer, because clips scoring under 7 are dropped. Source files are kept for 7 days and clips for 30, so download the ZIP rather than relying on the dashboard.

Limits to know before you paste

• Link import is for paid plans. The other way in is to upload an MP4 or MOV of up to 10 GB.
• The import fetches up to 1080p. This page states no resolution limit for uploaded files.
• The video must be at least 5 minutes long. Shorter files are not accepted for clipping.
• The ownership check is not a formality. The terms ask you to confirm that you either own each video you link or have permission to use it. For the wider question, see is it legal to clip YouTube videos.
• This page makes no claim about which spoken languages KeyMo supports. Test a short video first if your episode is not in English.

If you only need a caption file for your own video

YouTube generates automatic captions itself. Its help page says they come from machine learning, that quality varies, and that creators should always review and edit them. It says they are available on long-form videos and on Shorts, in a listed set of languages, and that live streams get automatic captions in English only. English automatic captions also support expressive captions, such as capitals for intensity and descriptions of sounds like sighs.

Once you have a file, the format question comes next. YouTube accepts SRT as a basic format and WebVTT as an advanced one; the SRT vs VTT guide has the details. And W3C's accessibility guidance is blunt about the draft: automatic captions need to be confirmed fully accurate before they meet accessibility requirements.