You would see the values during playback.
When nothing is being played, the device is closed. Why Windows can't handle SPDIF passthrough? Is it due to poor Windows drivers?
The first (Default) output has 'No passthrough capabilities' the second 'Digital Output (S/PDIF)' can send streamTypes: STREAM_TYPE_AC3, STREAM_TYPE_DTSHD_CORE, STREAM_TYPE_DTS_1024, STREAM_TYPE_DTS_512, STREAM_TYPE_DTS_2048. M_streamTypes : STREAM_TYPE_AC3,STREAM_TYPE_DTSHD_CORE,STREAM_TYPE_DTS_1024,STREAM_TYPE_DTS_512,STREAM_TYPE_DTS_2048The difference is deviceType (PCM vs. M_displayNameExtra: Digital Output (S/PDIF) M_displayName : CM6631A Audio Processor Digital Stereo (IEC958) M_deviceName : alsa_b-C-Media_Electronics_Inc._USB2.0_High-Speed_True_HD_Audio-00.iec958-stereo M_streamTypes : No passthrough capabilities M_displayNameExtra: Default Output Device