regarding subtitles - this fix works for me
edit SVP 4\extensions\tube\youtube_dl\utils.py, find the line starting with _USER_AGENT_TPL
remove this part - "AppleWebKit/537.36 (KHTML, like Gecko)"
the code should be like this:
_USER_AGENT_TPL = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/%s Safari/537.36'
restart SVP
for some odd reason the "AppleWebKit/537.36" part of the user agent string prevents ffmpeg from downloading subs from vrv server