Hi Max
My setup:
Device: FiiO M15
OS: Android 7
Library: flac only, 20000 Songs, 1TB Storage, High Res 24bit /44/48/96/176/192, Red Book 16 bit /22/44
High Res setting: 192
Following observation: If the High Res output is used, one CPU get utilized by 100%, it not depends on SW or SoX re-sampler, even enabling/disabling of the equalizer not changes the behavior. The Result is a fast battery drain and reduces the 10 hour playtime on balanced output with over ear mode (Denon AH-D7200) to 5 hour playtime. Unusable!
This is a bug in FiiO M15. But how ever it would be more