If you have just downloaded the subtitles for your favorite movie in a foreign language but are annoyed about the subtitle syncing, then you can try Jubler. It is a free subtitles editor and it works on many platforms including Windows, Linux and macOS.
Jubler is a Java based application and requires Java Runtimes Environment to be installed on the computer on which it needs to be run. But this also makes Jubler a cross-platform application and it runs on Windows, Linux, and macOS. In addition it also requires a media player to be installed which is mplayer for macOS and Linux, and Smplayer for Windows.
If you have Chocolatey installed on your PC, then you can install everything by using the command choco install jubler which is going to take care of all the extra tools needed as well as Java dependencies.
Jubler has a brilliantly designed user interface. The developer seems to be well versed in user experience. You can load a subtitle file and it is displayed with start time, end time and the dialogs for each of the lines. If the difference between the start and end time for a line is very short then it is displayed in red color. We can preview the edited subtitles by clicking on the play button which plays the associated video and the subtitles.
The software can be used to edit individual subtitles, to split subtitles, to join two or more subtitles, for time shifting in order to correct proper timing of the subtitles. This subtitles editor software also offers something that is not available in some other similar software – ability to change the frame rate of the subtitles. This is really useful in making the subtitles work with all kinds of videos even if with a different frame rate.
You can download Jubler Subtitles Editor from https://www.jubler.org/ or https://github.com/teras/Jubler.