Subtitle Appearance

[buzzcut16]

Hi, I have attached two screenshots containing the same subtitle for illustration. Both were taken from four different files (2 different video files and their 2 related srt files). I have sometimes noticed that subtitle bars can appear condensed or squashed and when they are like that they become tiring to read - they just hit the eye wrong.
It appears that changing any subtitle settings in "preferences" has no effect. If I swap srt files, that is, load the correct looking subtitle file on to the video that has been displaying the srt as squashed, it remains squashed. Does the problem therefore relate to the dimensions of the video file? If so, is there any way to compensate for this?
Thanks

Squashed

shot0518-min.png (359.44 KiB) Viewed 1202 times

Normal

shot0517-min.png (530.41 KiB) Viewed 1202 times

[rvm]

What's the resolution of the video?

[buzzcut16]

1280x720 for the video that shows subs squashed, 1920x1080 for the correct one. I just notice that for the correctly displayed subs, they extend beyond the image into the black letterboxed area, yet for the other file, the bottom of the image is the absolute bottom for the subs, if that makes sense, i.e. it is not possible for them to go into a black letterboxed area.

[rvm]

What video output are you using? (Preferences -> General -> Video).

What multimedia engine is selected? (mplayer or mpv)

The subtitles can be placed on the black border using the option Video -> Filters -> Add black borders.