import numpy as np # This function is obtained from librosa. def get_rms( y, *, frame_length=2048, hop_length=512, pad_mode="constant", ): padding = (int(frame_length // 2), int(frame_length // 2)) y = np.pad(y, padding, mode=pad_mode) axis = -1 # put our new within-frame axis at the end for now out_strides = y.strides + tuple([y.strides[axis]]) # Reduce the shape on the framing axis x_shape_trimmed = list(y.shape) x_shape_trimmed[axis] -= frame_length - 1 out_shape = tuple(x_shape_trimmed) + tuple([frame_length]) xw = np.lib.stride_tricks.as_strided( y, shape=out_shape, strides=out_strides ) if axis < 0: target_axis = axis - 1 else: target_axis = axis + 1 xw = np.moveaxis(xw, -1, target_axis) # Downsample along the target axis slices = [slice(None)] * xw.ndim slices[axis] = slice(0, None, hop_length) x = xw[tuple(slices)] # Calculate power power = np.mean(np.abs(x) ** 2, axis=-2, keepdims=True) return np.sqrt(power) class Slicer: def __init__(self, sr: int, threshold: float = -40., min_length: int = 5000, min_interval: int = 300, hop_size: int = 20, max_sil_kept: int = 5000): if not min_length >= min_interval >= hop_size: raise ValueError('The following condition must be satisfied: min_length >= min_interval >= hop_size') if not max_sil_kept >= hop_size: raise ValueError('The following condition must be satisfied: max_sil_kept >= hop_size') min_interval = sr * min_interval / 1000 self.threshold = 10 ** (threshold / 20.) self.hop_size = round(sr * hop_size / 1000) self.win_size = min(round(min_interval), 4 * self.hop_size) self.min_length = round(sr * min_length / 1000 / self.hop_size) self.min_interval = round(min_interval / self.hop_size) self.max_sil_kept = round(sr * max_sil_kept / 1000 / self.hop_size) def _apply_slice(self, waveform, begin, end): if len(waveform.shape) > 1: return waveform[:, begin * self.hop_size: min(waveform.shape[1], end * self.hop_size)] else: return waveform[begin * self.hop_size: min(waveform.shape[0], end * self.hop_size)] # @timeit def slice(self, waveform): if len(waveform.shape) > 1: samples = waveform.mean(axis=0) else: samples = waveform if (samples.shape[0] + self.hop_size - 1) // self.hop_size <= self.min_length: return [waveform] rms_list = get_rms(y=samples, frame_length=self.win_size, hop_length=self.hop_size).squeeze(0) sil_tags = [] silence_start = None clip_start = 0 for i, rms in enumerate(rms_list): # Keep looping while frame is silent. if rms < self.threshold: # Record start of silent frames. if silence_start is None: silence_start = i continue # Keep looping while frame is not silent and silence start has not been recorded. if silence_start is None: continue # Clear recorded silence start if interval is not enough or clip is too short is_leading_silence = silence_start == 0 and i > self.max_sil_kept need_slice_middle = i - silence_start >= self.min_interval and i - clip_start >= self.min_length if not is_leading_silence and not need_slice_middle: silence_start = None continue # Need slicing. Record the range of silent frames to be removed. if i - silence_start <= self.max_sil_kept: pos = rms_list[silence_start: i + 1].argmin() + silence_start if silence_start == 0: sil_tags.append((0, pos)) else: sil_tags.append((pos, pos)) clip_start = pos elif i - silence_start <= self.max_sil_kept * 2: pos = rms_list[i - self.max_sil_kept: silence_start + self.max_sil_kept + 1].argmin() pos += i - self.max_sil_kept pos_l = rms_list[silence_start: silence_start + self.max_sil_kept + 1].argmin() + silence_start pos_r = rms_list[i - self.max_sil_kept: i + 1].argmin() + i - self.max_sil_kept if silence_start == 0: sil_tags.append((0, pos_r)) clip_start = pos_r else: sil_tags.append((min(pos_l, pos), max(pos_r, pos))) clip_start = max(pos_r, pos) else: pos_l = rms_list[silence_start: silence_start + self.max_sil_kept + 1].argmin() + silence_start pos_r = rms_list[i - self.max_sil_kept: i + 1].argmin() + i - self.max_sil_kept if silence_start == 0: sil_tags.append((0, pos_r)) else: sil_tags.append((pos_l, pos_r)) clip_start = pos_r silence_start = None # Deal with trailing silence. total_frames = rms_list.shape[0] if silence_start is not None and total_frames - silence_start >= self.min_interval: silence_end = min(total_frames, silence_start + self.max_sil_kept) pos = rms_list[silence_start: silence_end + 1].argmin() + silence_start sil_tags.append((pos, total_frames + 1)) # Apply and return slices. if len(sil_tags) == 0: return [waveform] else: chunks = [] if sil_tags[0][0] > 0: chunks.append(self._apply_slice(waveform, 0, sil_tags[0][0])) for i in range(len(sil_tags) - 1): chunks.append(self._apply_slice(waveform, sil_tags[i][1], sil_tags[i + 1][0])) if sil_tags[-1][1] < total_frames: chunks.append(self._apply_slice(waveform, sil_tags[-1][1], total_frames)) return chunks def main(): import os.path from argparse import ArgumentParser import librosa import soundfile parser = ArgumentParser() parser.add_argument('audio', type=str, help='The audio to be sliced') parser.add_argument('--out', type=str, help='Output directory of the sliced audio clips') parser.add_argument('--db_thresh', type=float, required=False, default=-40, help='The dB threshold for silence detection') parser.add_argument('--min_length', type=int, required=False, default=5000, help='The minimum milliseconds required for each sliced audio clip') parser.add_argument('--min_interval', type=int, required=False, default=300, help='The minimum milliseconds for a silence part to be sliced') parser.add_argument('--hop_size', type=int, required=False, default=10, help='Frame length in milliseconds') parser.add_argument('--max_sil_kept', type=int, required=False, default=500, help='The maximum silence length kept around the sliced clip, presented in milliseconds') args = parser.parse_args() out = args.out if out is None: out = os.path.dirname(os.path.abspath(args.audio)) audio, sr = librosa.load(args.audio, sr=None, mono=False) slicer = Slicer( sr=sr, threshold=args.db_thresh, min_length=args.min_length, min_interval=args.min_interval, hop_size=args.hop_size, max_sil_kept=args.max_sil_kept ) chunks = slicer.slice(audio) if not os.path.exists(out): os.makedirs(out) for i, chunk in enumerate(chunks): if len(chunk.shape) > 1: chunk = chunk.T soundfile.write(os.path.join(out, f'%s_%d.wav' % (os.path.basename(args.audio).rsplit('.', maxsplit=1)[0], i)), chunk, sr) if __name__ == '__main__': main()