If you find a new subtitle file for your DVD, you can also import the subtitle and add in your DVD video.
On the main page, click the "Edit" icon beside your DVD title. And then go to the "Subtitle" section. Here you can easily turn on or off an embedded subtitle in your DVD and even preserve your needed subtitle in your converted DVD video. Click on the "Add" icon and then you can select and add your desired subtitle in the video.