In the past, when I use headphone to play DRM bluray, PowerDVD will force the output to 48kHz/16-bit even my hardware support 24-bit. In PowerDVD 16 Ultra, it selects 24-bit output by default, but I cannot hear anything. I have to switch output channels to some device that also supports 16-bit output and force PowerDVD 16 to out DRM bluray to 48/16 to hear sound in my headphone. I think it is a HDCP restriction because I can hear 24-bit output for no-DRM playback. But why PowerDVD 16 Ultra selects 24-bit instead of 16-bit by default? is that my hardware specific issue?

To see your Sound output, you need to hit D on the keyboard to display OSD info.