TEDSubtitleHunter is a subtitle downloader for ted.com. And then you can watch the TED talk mp4 video with the subtitle when you are offline
Usage:
TEDSubtitleHunter [talk ID] [language code]
[talk ID] It's from URL of ted.com website.
[language code] the language code for the subtitle.

The license of this software is Free, you can free download and free use this video utility software.