Hello and you’re welcome!
Regarding the question, I admit my answer is slightly embarrassing: I use Windows Live Movie Maker. Usually subbers would rely on an actual subbing application or website (such as Aegisubs, a free subbing application), but in my case, I am “old-school” with using Windows Movie Maker. However, I have found it to be reliable for simple subtitling
and have no technical troubles with it at all in comparison to others I have tried. (Also to clarify, “simple subtitling” in the sense that I would not be able to easily subtitle captions, etc.–though I cannot even read Korean in the first place so this does not matter.) Furthermore, rendering videos and such tends to be quite straightforward. As for the subtitling process, over time I have found many shortcuts that enable me to subtitle quickly and thus, no longer have issues in that realm.
(In the future I might write out a guide for those curious on how to make Windows Movie Maker very efficient for subtitling.)
Also, seeing a visual of my subtitles (difficult to explain without a picture) allows for easy editing and for quick changes to take place. The main issue with Windows Movie Maker is that my subtitles cannot be timed precisely and individually without being meticulous and slow–mostly because it is all manually done. (Hence the “line / next line” style I have to hasten the work. Actual subbing applications tend to do this part of the subtitling work: creating the subtitle itself. In Windows Movie Maker, I not only have to set up the caption timing, but I have to create the captions themselves. Even with shortcuts on that, it can be a longer process especially for longer videos with numerous dialogue.) Nevertheless, overall I am very satisfied with Windows Movie Maker, and after finding the mentioned shortcuts, I find it a reliable, easy, and even quick method to subtitle videos. I do not plan to switch any time soon (and more so after trying out four different subbing-oriented applications).
I hope this question helps, and if you happen to desire the guide on how I optimized Windows Movie Maker for subtitling, feel free to send another “ask.” I am always glad to help. Thank you for the question. (And to readers waiting for a review: I hope to finish one by today. Thanks to all for being patient.)