Combining two subtitle files is usually used to create multi language subtitles.
Multi language subtitles are useful when watching shows with someone that has a different native language than you do.
Subtitles with multiple languages can also help when studying a new language.
Merging subtitles can also be useful when your subtitles wrongly assume that the video has hard-coded subtitles for parts where a foreign language is spoken,
you can then merge subtitles for the foreign language into the original subtitle file.
This tool requires two files, a base file and a merge file.
The merge file will be merged into the base file.
The format of the base file will not be changed.
This tool has multiple modes for merging subtitles, they are described below.
Using the simple mode, the merge file will simply be merged into the base file.
The cues from both files are combined into one file.
Cue style and cue timings are not changed.
You can select the option to make the merge subtitle appear at the top of the screen.
Keep in mind that not all video players support showing subtitles on top of the screen.
The nearest cue merge is similar to the simple merge, except that you can set a nearest cue threshold value.
When merging cues from the merge file into the base file, the tool will look for nearby cues that are within the specified milliseconds threshold value.
If there are nearby cues, the merge cue will be appended to the base file cue that is the most nearby.
If there are no nearby cues, a new cue is created and added.
This mode usually gives the best results.
By appending the merge subtitle to the nearest cue, it prevents subtitles from jumping, which is caused by them appearing slightly earlier or later than the base subtitle.
You can select the option to make the merge subtitle appear at the top of the screen.
Keep in mind that not all video players support showing subtitles on top of the screen.
This mode works differently than the other modes.
The merge file is glued to the end of the base file, all the cue timings of the merge file are shifted to appear after the last cue from the base file has been shown.
The cues and timings from the base file are not changed.
The glue offset is used to set the time between the last cue from the base file, and the first cue from the merge file.
An example usage of this mode is if you have subtitles for cd1 and cd2, but your movie is one file.
Keep in mind that it might be very difficult to get subtitles that are in sync with the video when using this mode.
You might have to manually sync the subtitles with your video player.
If you want to permanently fix the sync of your glued subtitles, you can do this with the partial shifter tool.