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import time
import numpy as np
import torch
import torchaudio
from scipy.ndimage import maximum_filter1d, uniform_filter1d
def timeit(func):
def run(*args, **kwargs):
t = time.time()
res = func(*args, **kwargs)
print('executing \'%s\' costed %.3fs' % (func.__name__, time.time() - t))
return res
return run
# @timeit
def _window_maximum(arr, win_sz):
return maximum_filter1d(arr, size=win_sz)[win_sz // 2: win_sz // 2 + arr.shape[0] - win_sz + 1]
# @timeit
def _window_rms(arr, win_sz):
filtered = np.sqrt(uniform_filter1d(np.power(arr, 2), win_sz) - np.power(uniform_filter1d(arr, win_sz), 2))
return filtered[win_sz // 2: win_sz // 2 + arr.shape[0] - win_sz + 1]
def level2db(levels, eps=1e-12):
return 20 * np.log10(np.clip(levels, a_min=eps, a_max=1))
def _apply_slice(audio, begin, end):
if len(audio.shape) > 1:
return audio[:, begin: end]
else:
return audio[begin: end]
class Slicer:
def __init__(self,
sr: int,
db_threshold: float = -40,
min_length: int = 5000,
win_l: int = 300,
win_s: int = 20,
max_silence_kept: int = 500):
self.db_threshold = db_threshold
self.min_samples = round(sr * min_length / 1000)
self.win_ln = round(sr * win_l / 1000)
self.win_sn = round(sr * win_s / 1000)
self.max_silence = round(sr * max_silence_kept / 1000)
if not self.min_samples >= self.win_ln >= self.win_sn:
raise ValueError('The following condition must be satisfied: min_length >= win_l >= win_s')
if not self.max_silence >= self.win_sn:
raise ValueError('The following condition must be satisfied: max_silence_kept >= win_s')
@timeit
def slice(self, audio):
samples = audio
if samples.shape[0] <= self.min_samples:
return {"0": {"slice": False, "split_time": f"0,{len(audio)}"}}
# get absolute amplitudes
abs_amp = np.abs(samples - np.mean(samples))
# calculate local maximum with large window
win_max_db = level2db(_window_maximum(abs_amp, win_sz=self.win_ln))
sil_tags = []
left = right = 0
while right < win_max_db.shape[0]:
if win_max_db[right] < self.db_threshold:
right += 1
elif left == right:
left += 1
right += 1
else:
if left == 0:
split_loc_l = left
else:
sil_left_n = min(self.max_silence, (right + self.win_ln - left) // 2)
rms_db_left = level2db(_window_rms(samples[left: left + sil_left_n], win_sz=self.win_sn))
split_win_l = left + np.argmin(rms_db_left)
split_loc_l = split_win_l + np.argmin(abs_amp[split_win_l: split_win_l + self.win_sn])
if len(sil_tags) != 0 and split_loc_l - sil_tags[-1][1] < self.min_samples and right < win_max_db.shape[
0] - 1:
right += 1
left = right
continue
if right == win_max_db.shape[0] - 1:
split_loc_r = right + self.win_ln
else:
sil_right_n = min(self.max_silence, (right + self.win_ln - left) // 2)
rms_db_right = level2db(_window_rms(samples[right + self.win_ln - sil_right_n: right + self.win_ln],
win_sz=self.win_sn))
split_win_r = right + self.win_ln - sil_right_n + np.argmin(rms_db_right)
split_loc_r = split_win_r + np.argmin(abs_amp[split_win_r: split_win_r + self.win_sn])
sil_tags.append((split_loc_l, split_loc_r))
right += 1
left = right
if left != right:
sil_left_n = min(self.max_silence, (right + self.win_ln - left) // 2)
rms_db_left = level2db(_window_rms(samples[left: left + sil_left_n], win_sz=self.win_sn))
split_win_l = left + np.argmin(rms_db_left)
split_loc_l = split_win_l + np.argmin(abs_amp[split_win_l: split_win_l + self.win_sn])
sil_tags.append((split_loc_l, samples.shape[0]))
if len(sil_tags) == 0:
return {"0": {"slice": False, "split_time": f"0,{len(audio)}"}}
else:
chunks = []
# 第一段静音并非从头开始,补上有声片段
if sil_tags[0][0]:
chunks.append({"slice": False, "split_time": f"0,{sil_tags[0][0]}"})
for i in range(0, len(sil_tags)):
# 标识有声片段(跳过第一段)
if i:
chunks.append({"slice": False, "split_time": f"{sil_tags[i - 1][1]},{sil_tags[i][0]}"})
# 标识所有静音片段
chunks.append({"slice": True, "split_time": f"{sil_tags[i][0]},{sil_tags[i][1]}"})
# 最后一段静音并非结尾,补上结尾片段
if sil_tags[-1][1] != len(audio):
chunks.append({"slice": False, "split_time": f"{sil_tags[-1][1]},{len(audio)}"})
chunk_dict = {}
for i in range(len(chunks)):
chunk_dict[str(i)] = chunks[i]
return chunk_dict
def cut(audio_path, db_thresh=-30, min_len=5000, win_l=300, win_s=20, max_sil_kept=500):
audio, sr = torchaudio.load(audio_path)
if len(audio.shape) == 2 and audio.shape[1] >= 2:
audio = torch.mean(audio, dim=0).unsqueeze(0)
audio = audio.cpu().numpy()[0]
slicer = Slicer(
sr=sr,
db_threshold=db_thresh,
min_length=min_len,
win_l=win_l,
win_s=win_s,
max_silence_kept=max_sil_kept
)
chunks = slicer.slice(audio)
return chunks
def chunks2audio(audio_path, chunks):
chunks = dict(chunks)
audio, sr = torchaudio.load(audio_path)
if len(audio.shape) == 2 and audio.shape[1] >= 2:
audio = torch.mean(audio, dim=0).unsqueeze(0)
audio = audio.cpu().numpy()[0]
result = []
for k, v in chunks.items():
tag = v["split_time"].split(",")
result.append((v["slice"], audio[int(tag[0]):int(tag[1])]))
return result, sr