How to extract DVD subtitles to .srt using Avidemux in Windows/Linux/Mac OS
In this guide I will explain how to extract subtitles from a DVD disk and save them to a .srt file e.g. a text file containing the subtitles along with the timecode they appear in the movie. srt files can be easily edited or even translated to another language so that other users can view the movie. To do so we must first extract an .idx file from the DVD along with a .sub file. The .idx file contains the time codes of the subtitles and the .sub contains information about the image that contains the subtitles. The program I am going to use to rip the DVD subtitles is Avidemux. Avidemux has versions for Windows, Linux and Mac OS. In this tutorial I used Avidemux 2.4 on Archlinux running KDE4. The program has the same interface in all operating systems though. So, install Avidemux (if you are using Linux install it through your distributions Package Management System e.g. for Ubuntu sudo apt-get install avidemux and for Fedora su -c 'yum install avidemux' ) and lets extract the subs!
This is the main window of Avidemux.
Go to Tools -> VOB -> VobSub...
Press the first Open button next to VOB file(s).
Here you must select the .VOB file which has the beginning of the movie. It will start with VTS_ and have a few MB of size. In my example the correct file is VTS_01_0.VOB
Next press the second Open button next to IFO file. Here select the correct .IFO file depending on the .VOB you choose before. VTS_01_0.IFO is the correct one for me.
Next press the third Open button next to VobSub file. Here browse to where you want to save the extracted VobSub file. Here I have chosen /home/axel/Subtitles as the directory. Choose a name for the file and make sure it ends with .idx, subs.idx is the file for me. Now click the Save button.
When you have filled in all 3 fields press the OK button.
The ripping process will begin. Depending on your CPU and the movie's length it might take a few minutes to complete.
When the process is completed you will see two new files in the directory you choose before. subs.idx and subs.sub are the files.
Now it's time to make our .srt file e.g. the subtitles file. Go to Tools -> OCR (VobSub -> srt)...
In the Select input and output files window first press the Select idx file button.
In the VobSub Settings window press the Open button.
Now browse to where you have the subs.idx file, select it and press Open.
If the subs.idx file has more than one language you must select the one you want to extract from the drop down menu. Here I have selected the English subtitles. Press Ok.
Next press the Open button next to Output SRT file. Browse to where you want to save the final subtitles file, give it a name, e.g. subs.srt, and press Save.
If you have a GlyphSet from a previous time you can import it now. GlyphSet is a file that contains the letters of the alphabet along with their images. If it is the first time you make the whole process just leave it blank. A new GlyphSet will be created when you are finished with the ripping.
Now the OCR (Optical Character Recognition) program will start. Here you must teach the application what is each character. You must be very careful with that. The sentence you look at is the first subtitle line. In the small box all letters will appear one by one. You must type the right letter in the empty text field. When you type the correct press Ok to move on to the next one. This might seem boring at first, but when you have typed all letters of the alphabet the program will do the job by itself.
When you are finished press the Close button. Now the .srt file will have the extracted subtitles and the right timecodes in it!
You can save the GlyphSet for later use! Press the Open button and save it somewhere.
If you open the .srt file with a text editor you can check it by yourself.