""" This module provides scipy versions of high_pass_filter, and low_pass_filter as well as an additional band_pass_filter. Of course, you will need to install scipy for these to work. When this module is imported the high and low pass filters from this module will be used when calling audio_segment.high_pass_filter() and audio_segment.high_pass_filter() instead of the slower, less powerful versions provided by pydub.effects. """ from scipy.signal import butter, sosfilt from .utils import (register_pydub_effect,stereo_to_ms,ms_to_stereo) def _mk_butter_filter(freq, type, order): """ Args: freq: The cutoff frequency for highpass and lowpass filters. For band filters, a list of [low_cutoff, high_cutoff] type: "lowpass", "highpass", or "band" order: nth order butterworth filter (default: 5th order). The attenuation is -6dB/octave beyond the cutoff frequency (for 1st order). A Higher order filter will have more attenuation, each level adding an additional -6dB (so a 3rd order butterworth filter would be -18dB/octave). Returns: function which can filter a mono audio segment """ def filter_fn(seg): assert seg.channels == 1 nyq = 0.5 * seg.frame_rate try: freqs = [f / nyq for f in freq] except TypeError: freqs = freq / nyq sos = butter(order, freqs, btype=type, output='sos') y = sosfilt(sos, seg.get_array_of_samples()) return seg._spawn(y.astype(seg.array_type)) return filter_fn @register_pydub_effect def band_pass_filter(seg, low_cutoff_freq, high_cutoff_freq, order=5): filter_fn = _mk_butter_filter([low_cutoff_freq, high_cutoff_freq], 'band', order=order) return seg.apply_mono_filter_to_each_channel(filter_fn) @register_pydub_effect def high_pass_filter(seg, cutoff_freq, order=5): filter_fn = _mk_butter_filter(cutoff_freq, 'highpass', order=order) return seg.apply_mono_filter_to_each_channel(filter_fn) @register_pydub_effect def low_pass_filter(seg, cutoff_freq, order=5): filter_fn = _mk_butter_filter(cutoff_freq, 'lowpass', order=order) return seg.apply_mono_filter_to_each_channel(filter_fn) @register_pydub_effect def _eq(seg, focus_freq, bandwidth=100, mode="peak", gain_dB=0, order=2): """ Args: focus_freq - middle frequency or known frequency of band (in Hz) bandwidth - range of the equalizer band mode - Mode of Equalization(Peak/Notch(Bell Curve),High Shelf, Low Shelf) order - Rolloff factor(1 - 6dB/Octave 2 - 12dB/Octave) Returns: Equalized/Filtered AudioSegment """ filt_mode = ["peak", "low_shelf", "high_shelf"] if mode not in filt_mode: raise ValueError("Incorrect Mode Selection") if gain_dB >= 0: if mode == "peak": sec = band_pass_filter(seg, focus_freq - bandwidth/2, focus_freq + bandwidth/2, order = order) seg = seg.overlay(sec - (3 - gain_dB)) return seg if mode == "low_shelf": sec = low_pass_filter(seg, focus_freq, order=order) seg = seg.overlay(sec - (3 - gain_dB)) return seg if mode == "high_shelf": sec = high_pass_filter(seg, focus_freq, order=order) seg = seg.overlay(sec - (3 - gain_dB)) return seg if gain_dB < 0: if mode == "peak": sec = high_pass_filter(seg, focus_freq - bandwidth/2, order=order) seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB sec = low_pass_filter(seg, focus_freq + bandwidth/2, order=order) seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB return seg if mode == "low_shelf": sec = high_pass_filter(seg, focus_freq, order=order) seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB return seg if mode=="high_shelf": sec=low_pass_filter(seg, focus_freq, order=order) seg=seg.overlay(sec - (3 + gain_dB)) +gain_dB return seg @register_pydub_effect def eq(seg, focus_freq, bandwidth=100, channel_mode="L+R", filter_mode="peak", gain_dB=0, order=2): """ Args: focus_freq - middle frequency or known frequency of band (in Hz) bandwidth - range of the equalizer band channel_mode - Select Channels to be affected by the filter. L+R - Standard Stereo Filter L - Only Left Channel is Filtered R - Only Right Channel is Filtered M+S - Blumlien Stereo Filter(Mid-Side) M - Only Mid Channel is Filtered S - Only Side Channel is Filtered Mono Audio Segments are completely filtered. filter_mode - Mode of Equalization(Peak/Notch(Bell Curve),High Shelf, Low Shelf) order - Rolloff factor(1 - 6dB/Octave 2 - 12dB/Octave) Returns: Equalized/Filtered AudioSegment """ channel_modes = ["L+R", "M+S", "L", "R", "M", "S"] if channel_mode not in channel_modes: raise ValueError("Incorrect Channel Mode Selection") if seg.channels == 1: return _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order) if channel_mode == "L+R": return _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order) if channel_mode == "L": seg = seg.split_to_mono() seg = [_eq(seg[0], focus_freq, bandwidth, filter_mode, gain_dB, order), seg[1]] return AudioSegment.from_mono_audio_segements(seg[0], seg[1]) if channel_mode == "R": seg = seg.split_to_mono() seg = [seg[0], _eq(seg[1], focus_freq, bandwidth, filter_mode, gain_dB, order)] return AudioSegment.from_mono_audio_segements(seg[0], seg[1]) if channel_mode == "M+S": seg = stereo_to_ms(seg) seg = _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order) return ms_to_stereo(seg) if channel_mode == "M": seg = stereo_to_ms(seg).split_to_mono() seg = [_eq(seg[0], focus_freq, bandwidth, filter_mode, gain_dB, order), seg[1]] seg = AudioSegment.from_mono_audio_segements(seg[0], seg[1]) return ms_to_stereo(seg) if channel_mode == "S": seg = stereo_to_ms(seg).split_to_mono() seg = [seg[0], _eq(seg[1], focus_freq, bandwidth, filter_mode, gain_dB, order)] seg = AudioSegment.from_mono_audio_segements(seg[0], seg[1]) return ms_to_stereo(seg)