def pitch_shift_on_lpc_residual(
wav,
sr,
shift_in_cent,
frame_length=4096,
hop_length=240,
mgc_order=59,
):
assert wav.dtype == np.int16
frames = (librosa.util.frame(wav,
frame_length=frame_length,
hop_length=hop_length).astype(np.float64).T)
frames *= pysptk.blackman(frame_length)
alpha = pysptk.util.mcepalpha(sr)
mgc = pysptk.mcep(frames, mgc_order, alpha, eps=1e-5, etype=1)
c = pysptk.freqt(mgc, mgc_order, -alpha)
lpc = pysptk.levdur(pysptk.c2acr(c, mgc_order, frame_length))
# remove gain
lpc[:, 0] = 0
# Compute LPC residual
synth = Synthesizer(AllZeroDF(mgc_order), hop_length)
wav_lpc = synth.synthesis(wav.astype(np.float64), -lpc)
residual = wav - wav_lpc
# Pitch-shift on LPC residual
residual_shifted = librosa.effects.pitch_shift(residual,
sr=sr,
n_steps=shift_in_cent,
bins_per_octave=1200)
# Filtering by LPC
synth = Synthesizer(AllPoleDF(mgc_order), hop_length)
wav_shifted = synth.synthesis(residual_shifted, lpc)
return wav_shifted.astype(np.int16)
def __test(order):
__test_synthesis(AllPoleDF(order))
def __test(order):
__test_synthesis(AllPoleDF(order))
__test_synthesis_levdur(AllPoleDF(order))
# 音声の切り出しと窓掛け
frames = librosa.util.frame(x,
frame_length=FRAME_LENGTH,
hop_length=HOP_LENGTH).astype(np.float64).T
frames *= pysptk.blackman(FRAME_LENGTH) # 窓掛け（ブラックマン窓）
# ピッチ抽出
pitch = pysptk.swipe(x,
fs=fs,
hopsize=HOP_LENGTH,
min=MIN_F0,
max=MAX_F0,
otype="pitch")
# 励振源信号(声帯音源)の生成
source_excitation = pysptk.excite(pitch, HOP_LENGTH)
# 線形予測分析による線形予測係数の抽出
lpc = pysptk.lpc(frames, ORDER)
lpc[:, 0] = np.log(lpc[:, 0])
# 全極フィルタの作成
synthesizer = Synthesizer(AllPoleDF(order=ORDER), HOP_LENGTH)
# 励振源信号でフィルタを駆動して音声を合成
y = synthesizer.synthesis(source_excitation, lpc)
# 音声の書き込み
y = y.astype(np.int16)
wavfile.write(OUT_WAVE_FILE, fs, y)