Thanks for the tips.When you cast audio from the Google home app on your phone to WiiM, and play the video on the Youtube app, the audio will be output from WiiM.
Hmm. The song was recorded only once in HiRes. I assume the record label down sampled it to different quality for Amazon. One interesting thing I notice is when I lower Wiim output resolution, the same track sometimes shows different kbps even though it is showing the same kHz and bits. Looks like there is no relationship between kbps and kHz/bits.Amazon provides multiple audio quality files (SD/HD/UHD) for each track. These different files are automatically selected by the user's playback environment.
Therefore, Amazon and WiiM do not need to use down sampling. This is also the case with other Hi-Res streaming services.