What was the length of the waveform you were trying to downshift? I can see this happening if it's too short (a few seconds). I'll add some checks into the code to handle this.

DeltaWave v1.0.32, 2019-07-01T00:23:47.6140876+08:00

Reference: no gpu_48kHz.wav[L+R] 949920 samples 48000Hz 24bits, stereo, MD5=00

Comparison: ALC892_48kHz.wav[L+R] 950880 samples 48000Hz 24bits, stereo, MD5=00

Settings:

Gain:True, Remove DC:True

Non-linear Gain:False EQ FFT Size:65536, EQ Frequency Cut: 0Hz - 0Hz, EQ Threshold: -160dB

Correct Drift:True, Precision:30

Non-Linear drift Correction:True

Upsample:False, Window:Hann

Spectrum Window:Hann, Spectrum Size:32768

Spectrogram Window:Hann, Spectrogram Size:4096, Spectrogram Steps:2048

Dither:False

Trim Silence:False

Discarding Reference: Start=0s, End=0s

Discarding Comparison: Start=0s, End=0s

Initial peak values Reference: -2.981dB Comparison: -7.896dB

Initial RMS values Reference: -11.858dB Comparison: -16.77dB

Null Depth=14.028dB

X-Correlation offset: -1011 samples

Drift computation quality, #1: Excellent (0.11μs)

Trimmed 0 samples ( 0.00ms) front, 0 samples ( 0.00ms end)

Final peak values Reference: -2.981dB Comparison: 1.975dB

Final RMS values Reference: -11.858dB Comparison: -6.954dB

Gain= -9.8735dB (0.3209x) DC=0 Phase offset=-21.429583ms (-1028.62 samples)

Difference (rms) = -14.22dB [-15.91dBA]

Correlated Null Depth=9.31dB [6.26dBA]

Clock drift: 47.57 ppm

Files are NOT a bit-perfect match (match=2.41%) at 16 bits

Files are NOT a bit-perfect match (match=0.01%) at 24 bits

Files match @ 49.9986% when reduced to 3.7 bits

Phase difference (full bandwidth): 103.761977355399°

0-10,000Hz: 104.018508239229°

0-20,000Hz: 103.870015062889°

0-24,000Hz: 103.761977355399°

0-44,100Hz: 103.761977355399°

0-48,000Hz: 103.761977355399°

RMS of the difference of spectra: -54.1886895225997dB

Timing error (rms): 99.5μs

gn=3.11656897199226, dc=0, dr=4.7566722E-05, of=-1028.6199738479

DONE!

Signature: b7805c8d20e2a5a1fda0147fd68a8c58

Phase difference (full bandwidth): 104.017312219896°

0-10,000Hz: 104.696844200809°

0-20,000Hz: 104.292013701913°

0-24,000Hz: 104.017312219896°

0-44,100Hz: 104.017312219896°

0-48,000Hz: 104.017312219896°