Now the new Desktop release is also out.
For example if one boots up latest HQPlayer OS on UP Gateway with the USB OTG set to Device mode, in HQPlayer Desktop select “hqplayer:USB Audio (DWC3)” as input device. Connect your source device with USB → microB cable to the UP Gateway USB 3 OTG port.
If you use RPi4 with HQPlayer OS, before bootin up with new image, edit the config.txt first and on the last lines swap the ‘#’ prefix so that the dwc2 host mode line has ‘#’ (commented out) and the dwc2 peripheral mode line has ‘#’ removed. In HQPlayer instead select “hqplayer:USB Audio (RPi4)” as input device. Connect your source device with USB → type-C cable to the RPi4 Type-C port. Since the RPi4 can draw quite a bit of power, you may have best results if you can use type-C → type-C cable for connecting. You will need to use at least USB3 → type-C cable on USB3 port to supply enough current.
In HQPlayer Desktop, for source URI line (above playback queue display) enter “audio:default/0/2” and hit enter. Now it should appear on the playback queue. Then just start playback. Now the NAA should appear as a USB DAC on the source device. When you start playing something, HQPlayer time should start proceeding and you should hear what ever you play on the source device. I’ve tested mostly with my old iPad Pro through the Apple’s Lightning to USB3 adapter dongle which also allows simultaneous charging of iPad.