YouTube Double Subtitle is a free Chrome add-on developed by robertkao5656. It falls under the category of Browsers and is specifically classified as an Add-ons & Tools subcategory. This program allows users to enable double subtitles on YouTube videos.

With YouTube Double Subtitle, users have the option to choose between three different translate modes for the second subtitle. The first option is "Off," which disables the display of the second subtitle. The second option is "YouTube," where the second subtitle is sourced directly from YouTube, provided that the video supports the selected language. The third option is "Online," which retrieves the second subtitle from an online translation service.

Users can also select the language for the second subtitle, although the add-on currently supports only four languages. It is important to note that if the "YouTube" translate mode is selected, the video must support the chosen language for the second subtitle. Additionally, if the video does not have subtitles enabled, users must enable them. If subtitles are already enabled, users are advised to disable and re-enable them for correct display.

Please refresh the browser after changing the translate mode or language. It is worth mentioning that selecting the "Online" translate mode may take some time, particularly for longer videos. For a one-hour video, the translation process may take several minutes.