It worked perfectly for me
Hi,
Just purchased/downloaded this app last night. My files types are mkv and the software worked flawlessly to extract the subtitle files and leave them as srt files in separate folders. I suggest having each mkv file in a separate folder and then opening this application, clicking the green add button, searching for the mkv video file in the folder you created, adding to the software engine, and processing the extraction. You will then find the extracted srt file in an auto-generated folder within the original mkv folder you created.
I have not tried this software with other video types, just with mkv.
User345674 about Subtitle Extractor