Maybe (... likely ...) all 32 bit files, but certainly not 24 or 16, cf the error message I pasted above.
Of course I meant 32-bit. Because even if someone managed to create a 16 or 24 bits float file it will not be supported by all other third party programs and hardware player. It requires a special decoder:
https://hydrogenaud.io/index.php/topic,90770.0.html
Originated from, that is question for when input file is integer. ("32-bit integer"?). BTW, to other readers: that option is as of now only in a beta.
I have yet to see WavPack mis-identify input files.
I meant if you see obvious size differences when using --optimize-32bit, then the file is likely converted from another 32-bit format. So this 810MB file is encoded in integer, but because --optimize-32bit can further reduce the file size significantly, then it means the file was originally processed in float, but exported to integer. So it is not about misinterpretation of file encoding formats. The file can be compressed to 537MB without using -h or -x when using --optimize-32bit.
[edit]
Tested other settings using --optimize-32bit and --threads=8
561,864,578 gx4.wv
561,532,860 gx6.wv
555,605,858 hx4.wv
555,328,064 hx6.wv
553,126,794 hhx4.wv
553,009,866 hhx6.wv