Sub is a powerful Firefox plugin designed to improve multimedia experiences by facilitating the addition of subtitles to videos. It supports popular streaming platforms such as Amazon Video, Netflix, and YouTube, allowing users to load subtitles with ease. The interface is user-friendly, making it accessible for all users, regardless of technical expertise. A built-in search feature powered by TMDB and OpenSubtitles ensures that users can find subtitles in their preferred language quickly.

In addition to loading subtitles, Sub includes synchronization capabilities to adjust the timing of subtitles to match the video dialogue accurately. The plugin also features a transcript view that allows users to copy subtitles easily using a keyboard shortcut. Furthermore, users can click on specific points in the transcript to navigate through the video, enhancing the overall viewing experience.