This article describes how to use a free program called Subler to add subtitle tracks to MP4 videos. Subler requires Mac OS X 10.6 or later, and is available for free download.
- Subler for Mac OS X
- An MP4 version of the video that you want to add subtitles to
- SRT output format caption file(s). Note that you will need one file for each subtitle language that you want to add to the video.
Note that Subler uses a process called muxing to inject the subtitles into your video file without any new encoding, and it simply edits the file that you open and saves it with the same name. For this reason, you may want to make a copy of your video before starting this process.
The first step is to start up Subler and use File -> Open to open your video. When you first start Subler it does not have a GUI window active, but you can select it from your Dock and then use the File menu to open your target video.
Next you can add a subtitle track to the video by clicking on the + icon in the upper left and selecting the SRT file that contains your subtitles. The default are fine if you are using an SRT file, so click Add when prompted.
If the SRT file contained subtitles in a language other than English, you can now select the language using the pull-down menu. Repeat the process of adding tracks and selecting language for each subtitle track on the video.
Once you have selected all the subtitle languages you can add the video to the processing queue using the Share button in the upper right.
If you have multiple videos that you want to process at the same time, you can repeat the steps above with additional videos, adding them to the queue. The Subler icon in your dock will show how many videos you have added to the queue.
Once you are ready to process the files, go to Window -> Queue. Your queue window will show all the videos that you have added. Click Start to process the video(s).
Adding subtitles is quite quick, since no transcoding is performed. You will see green check marks next to the files that were processed when the processing is complete.
You can now open the updated files using Quicktime, then select the subtitle language, and verify that the video shows the subtitles.
Note: Attached to this article is the video above that we added subtitles to using Subler. The method described above using Subler produces a video that allows subtitles to be displayed using Quicktime 10, iTunes, and iOS devices. However, it does not work for Quicktime 7 and some versions of Windows Media Player. Feel free to download this sample and test it to see if this method of subtitling will work for your needs.