Hello I am using a Denon Prime 4 and when I look at the Tracks which are on my USB Drive, it doesn‘t Show me the BPM or Key, online when I Lord them in the separate playlist it Shows them.
Are you looking at raw directories? If so, they likely were not analyzed. Adding to a playlist likely causes the analysis.
In the playlist I can see it, but is it also possible in the folder
I don’t think it would be because the files need to be analyzed. Key and BPM are detected by the software literally scanning the contents of the music file and running those contents against mathematical algorithms for beat detection (BPM) and Key.
Browsing a folder would be incredibly slow if it did this. Even scanning each file’s metadata (assuming the key and bpm are stored there) would be pretty slow and not very usable in a touch-based interface.