Gnome Subtitles is free and easy to use.
Gnome Subtitles is a tool for creating and editing subtitles for videos. It offers various features that are listed below.
This program can also be used for editing existing subtitle files. It supports almost all known formats such as SRT, Subviewer, MPSub, SubRip and over more. Among the possibilities are changing font types and color, resizing them and so on.
With Gnome Subtitles, the user is given the ability to easily sync subtitles with video sequences. This is particularly useful after converting a video to MP4 and subtitles are separated from the original movie.
This software is downloadable for free.