How to Edit Video Subtitles with Aegisub

Aegisub is a simple subtitle editor with advanced functionality. It is an excellent program for editing and adjusting subtitles and also getting a live preview of the video or audio files in real time.

Aegisub is available for Windows, Mac and Linux.

For Mac and Windows, you can download Aegisub installer from its website.

For Linux, if you are using Ubuntu (or Ubuntu-based distro), you can install it with the following command:

sudo apt-get install aegisub

For other distributions, you can get the source code with

wget http://ftp.aegisub.org/pub/archives/releases/source/aegisub-3.2.2.tar.xz

Unpack the file and follow the instructions to compile and install it.

The Aegisub user interface is quite simple, although the number of menu options can look intimidating at first.

aegisub-start

The User Interface consists of four major parts: the Video box (1), the Audio box (2), the Edit box (3) and  the Subtitle grid (4). The Subtitle grid and Edit box are only visible at startup. The other two, the Video and Audio boxes, are only available if you open a video (Video -> Open Video…) or audio file (Audio -> Open Audio File…) or open an audio from the previously opened video file (Audio -> Open Audio From Video).

aegisub-interface

There are plenty of (rather small) buttons that allow the user to easily access some of the functions. The buttons are, unfortunately, not very intuitive. You will have to hover your mouse and look at the tooltips to understand what each button is for. Nevertheless, the functions these buttons represent are worth having a look at.

The most basic use case would be to load a subtitle file (File -> Open Subtitles…) with a matching video file (File -> Open Video…) and open the audio stream straight from the video (Audio -> Open Audio From Video), unless it is available separately (Audio -> Open Audio File…).

You then have fine control over the subtitles. You have some “visual typesetting” buttons to the left of the video box that will allow you to interact with the picture and subtitles.

aegisub-visual-typesetting

To edit a line, find and highlight it in the “subtitle grid” (double clicking it will make the video jump there too),

aegisub-sub-grid

then edit it in the “edit box.”

aegisub-sub-edit-box

Other than the subtitle text, you can also change the font properties like weight, style, color, etc.

Once you are done with the edit, press Enter or click the tick button to commit to the changes. Aegisub will automatically move to the next line of the subtitle.

If you need to adjust the subtitles to the audio or image (or both), the video and audio boxes are useful, as they allow you to drag the subtitle to the position you want it to appear and still get a live preview of how it appears in the video. The “Timing” menu also has several useful tools including “Shift times” that allows you to adjust all lines at once,

aegisub-timing-shift

and “Timing post processor” that allows for finer tuning of the timing with relative ease.

aegisub-timing-postprocessor

The “Subtitles” menu offers many more tools that make Aegisub a powerful subtitles processor,

aegisub-subtitles-menu

while the various automation scripts (Automation -> Automation… ) make regular tasks easier. You can even write your own script if you like.

aegisub-automation-scripts

If you need to adjust, edit, or even create new subtitles for a video file, Aegisub is truly an excellent choice. It offers powerful functionality, and while it looks difficult to use at first, it is quite easy to get used to the interface. Of course, its functionality extends well beyond this short introduction. If you are interested in learning more, visit Agegisub’s website, and read one of the excellent manuals available online.