Until three days ago I could watch movies and listening music fine
Something must have changed during those days. Is the integrity of your video files still okay? They may be on a NAS, but that doesn't mean they are indestructible.
I'm not a video expert, but there is constant moaning by the video player. And some audio hiccups too. Is every video you play this way? I can tell they are not the most legal of video files, meaning this is not an official video rip. So if the person doing the recode did a horrible job, there is not much that Kodi can fix.