The problem with ripped DVDs is that in many / most cases the correct AR is stored only at container level. When demuxxing the video to a mpg2 elementary stream, this information is lost. Within the mpg2 elementary stream, each sequence header contains an AR flag, which allows four differerent aspect ratios:
1 = 1:1 (square pixel)
2 = 4:3
3 = 16:9
4 = 2.211 (not used in dvd)
And this flag is very often not set to the correct value by the company which authored the DVD, with the result that a 16:9 stream is falsely detected as 4:3 after demuxxing. If you are interested in the details you may have a look here:
https://forum.videohelp.com/threads/...-4-3-16-9-flag
I am not working with ripped DVDs as source for a long time, but when ever it was needed, I used the mentioned program "restream" to set the AR flag to 16:9 if neccessary.