Hi
The latest version of FLAC was released a few weeks ago. Among the new features is 32 bit encoding, and higher sample rate handling.
Details here: FLAC - FLAC 1.4.1 released
It would be great if Volumio could support this! Is there any prospect this is possible? Thanks 
Just curious, how many albums have been released with a 1,048,575 Hz sampling rate? I suspect that there are more pressing features to build or bugs to fix 
These are files processed using the PGGB upsampling app. remastero - PCM reimagined
Think this not the place to discuss the ins and outs, but the files sound absolutely amazing. Kind of like the Signalyst HQ Player, but creating your own files. They are however pretty massive, hence the attractiveness of FLAC which can encode said big files.
FLAC installation itself probably doesn’t do much. I suppose that MPD is piece what needs to be updated in this case to support FLAC 1.4 features. If I remember correctly MPD is rarely updated on Volumio, it is probably modified by dev team and needs custom patches reapplied again. Am I correct?
If I remember correctly, there was discussion about custom/high sample rates in FLAC-dev mailing list. Somebody used FLAC to compress raw data streams from laserdisc dumps and adapted FLAC to compress these non-audio streams to save space. ~1MHz probably isn’t laserdisc data rate but maybe it can more precisely hold value that is used to get correct data rate. I don’t believe that support for these high sample rates was based on audio related stuff.
Off topic: Wavpack should also do very high sample rate PCM and even DSD. I use it to compress DSD files.
Thanks - yes, Wavpack is great. FLAC easier though for metadata IME though 
We don’t patch it. Just we are very conservative when updating it, since we’ve had many unexpected regressions in the past