How to download videos from YouTube with subtitles

Google implemented the Web Speech API (both for speech recognition and synthesis) into Chrome, which you can use if you are a developer. This is what YouTube uses to generate close captioning on some videos. Maybe you'll find code to interact with it.

The data flow would probably be:

A video file => extract and convert audio => send it to Google API => get the text => write into a SRT.

EDIT: there doesn't seem to be an official API page, other than the W3C spec. So here are more links:

• http://www.sitepoint.com/experimenting-web-speech-api/
• http://www.smashingmagazine.com/2014/12/05/enhancing-ux-with-the-web-speech-api/

These examples are about using the API from inside Chrome, but you can directly query Google's online speech recognition engine. For instance, Jasper, a speech-recognizing personal assistant for Raspberrry Pi, lets you choose Google as the speech recognition engine.

According to the Readme file for youtube-dl (the program you run as the file yt-dl.py), --write-srt is not an option, but --write-sub is. The Readme file with all options is available here: https://github.com/rg3/youtube-dl/blob/master/README.md#readme

I successfully downloaded a video with subtitles using yt-dl.py --sub-lang en --convert-subs srt --write-sub <youtube url>. --sub-lang en chooses english subtitles, --convert-subs srt converts the subtitles to the common SubRib (.srt) format, --write-sub writes the subtitles to a .srt file and <youtube url> is simply the URL/web address of the youtube video page.

An example: yt-dl.py --sub-lang en --convert-subs srt --write-sub https://www.youtube.com/watch?v=sWAN0FwfD5M

If you use the windows executable, launch your DOS-prompt, navigate to your youtube-dl.exe file and write e.g: youtube-dl.exe --sub-lang en --convert-subs srt --write-sub https://www.youtube.com/watch?v=sWAN0FwfD5M. The --convert-subs command will not work if you do not have the ffmpeg program installed. If that is the case, you have to omit this option and youtube-dl will output .vtt subtitles instead.