SubViewer

SubViewer is a lightweight tool designed to provide you with a simple solution for adding or synchronizing subtitle files to your videos. Designed with ease of use in mind, it can be used for performing small subtitle adjustments and sync the text with the video playback.
The application supports a wide range of media files (MPEG, AVI, MPE, ASX, WMA, MOV, WAV, WMV, MP2, MP3, M3U and more). Despite its name, it can open multiple subtitle formats, other than SUB, such as SRT, SMI, SSA, TXT, IDX and LRC. Opened SUB files can be saved as SRT subtitles.
In order to synchronize the subtitle to the video content, you can change its frame rate (FILM, PAL, NTSC or other), as well as add delay to the text. The zoom level and the font color are also customizable. An interesting feature of the application is its ability to display transparent subtitles, which you can use to superimpose the text on any video.
Shortcut keys, volume adjustment and playback options are other features of this software. Drag and drop support, together with the simple, clean interface makes it very intuitive and suitable for any type of user, beginner or advanced.
Since it can open multiple video formats, SubViewer can be used as a simple player for watching movies. However, subtitle synchronization remains its main purpose.
SubViewer became more popular since YouTube announced official support for captions uploaded in SUB and SRT format. It remains a handy and reliable utility that allows you to generate synchronized subtitles for your videos or movies.