Kieshi sure. after some search I found a way to know about this information. I checked all the files (I ripped them myself from physical DVDs long ago).
video: all of them are in AVC @1920x1080p resolution.
audio: all of them are in AC-3/ 2 Channels/ Bitrate: 192kbps
all of them worked with modern windows media player (when I had a windows 10 laptop) and all of them worked with deovr app previously without any issue. I don't know why the audio didn't work suddenly.
could it be because of meta os latest update?
maybe broke something with deovr compatibility when it comes to internal storage?
I'm on latest update v78 and deovr app is on latest update as well.
please tell me if you need any more information and thank you very much!