import os from argparse import ArgumentParser import librosa import soundfile import numpy as np class Slicer: def __init__( self, sr: int, threshold: float = -40.0, 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("min_length >= min_interval >= hop_size is required") if not max_sil_kept >= hop_size: raise ValueError("max_sil_kept >= hop_size is required") min_interval = sr * min_interval / 1000 self.threshold = 10 ** (threshold / 20.0) 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): start_idx = begin * self.hop_size if len(waveform.shape) > 1: end_idx = min(waveform.shape[1], end * self.hop_size) return waveform[:, start_idx:end_idx] else: end_idx = min(waveform.shape[0], end * self.hop_size) return waveform[start_idx:end_idx] def slice(self, waveform): samples = waveform.mean(axis=0) if len(waveform.shape) > 1 else waveform if samples.shape[0] <= 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, clip_start = None, 0 for i, rms in enumerate(rms_list): if rms < self.threshold: if silence_start is None: silence_start = i continue if silence_start is None: continue 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 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 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)) if not sil_tags: 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 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 out_strides = y.strides + tuple([y.strides[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) slices = [slice(None)] * xw.ndim slices[axis] = slice(0, None, hop_length) x = xw[tuple(slices)] power = np.mean(np.abs(x) ** 2, axis=-2, keepdims=True) return np.sqrt(power) def main(): 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, default=-40, help="The dB threshold for silence detection", ) parser.add_argument( "--min_length", type=int, default=5000, help="The minimum milliseconds required for each sliced audio clip", ) parser.add_argument( "--min_interval", type=int, default=300, help="The minimum milliseconds for a silence part to be sliced", ) parser.add_argument( "--hop_size", type=int, default=10, help="Frame length in milliseconds" ) parser.add_argument( "--max_sil_kept", type=int, default=500, help="The maximum silence length kept around the sliced clip, presented in milliseconds", ) args = parser.parse_args() out = args.out or 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"{os.path.basename(args.audio).rsplit('.', maxsplit=1)[0]}_{i}.wav", ), chunk, sr, ) if __name__ == "__main__": main()