The reason why the extension is observed is so that similar named files can be renamed when renaming a video file (eg. nfo, srt, jpg, etc).
Think of this scenario:
A user has a directory with one or more video files, and a few similar named files (for example subtitles).
This same user has the option "rename similar named files" enabled, and drops the entire directory on it.
So under the current approach, only video files will be added, and during the rename process, RMTV will look for similar named files and rename them as well.
If I would disable the filtering of non video files (allow any file), all the extra files will now be listed as well in RMTV.
If the user would then rename files, with the option "rename similar named files" enabled, you can already imagine the chaos that may follow.
Also note that I wrote RMTV just to rename TV Shows, and not just any files.
That said: I could implement the option to "accept any file". If that option is selected, "rename similar named files" will then be disabled and vice versa. 😊
This shouldn't be too hard, but I am worried about other use cases. (you wouldn't believe the different ways people use RMTV)
I've added it to my "to-do" list. We will see how good or bad this option will be in the future.