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import sys
import torch
import numpy as np
import scipy.signal
from numba import jit
from deepafx_st.processors.processor import Processor
# Adapted from: https://github.com/drscotthawley/signaltrain/blob/master/signaltrain/audio.py
@jit(nopython=True)
def my_clip_min(
x: np.ndarray,
clip_min: float,
): # does the work of np.clip(), which numba doesn't support yet
# TODO: keep an eye on Numba PR https://github.com/numba/numba/pull/3468 that fixes this
inds = np.where(x < clip_min)
x[inds] = clip_min
return x
@jit(nopython=True)
def compressor(
x: np.ndarray,
sample_rate: float,
threshold: float = -24.0,
ratio: float = 2.0,
attack_time: float = 0.01,
release_time: float = 0.01,
knee_dB: float = 0.0,
makeup_gain_dB: float = 0.0,
dtype=np.float32,
):
"""
Args:
x (np.ndarray): Input signal.
sample_rate (float): Sample rate in Hz.
threshold (float): Threhold in dB.
ratio (float): Ratio (should be >=1 , i.e. ratio:1).
attack_time (float): Attack time in seconds.
release_time (float): Release time in seconds.
knee_dB (float): Knee.
makeup_gain_dB (float): Makeup Gain.
dtype (type): Output type. Default: np.float32
Returns:
y (np.ndarray): Output signal.
"""
# print(f"dsp comp fs = {sample_rate}")
N = len(x)
dtype = x.dtype
y = np.zeros(N, dtype=dtype)
# Initialize separate attack and release times
# Where do these numbers come from
alpha_A = np.exp(-np.log(9) / (sample_rate * attack_time))
alpha_R = np.exp(-np.log(9) / (sample_rate * release_time))
# Turn the input signal into a uni-polar signal on the dB scale
x_G = 20 * np.log10(np.abs(x) + 1e-8) # x_uni casts type
# Ensure there are no values of negative infinity
x_G = my_clip_min(x_G, -96)
# Static characteristics with knee
y_G = np.zeros(N, dtype=dtype)
# Below knee
idx = np.where((2 * (x_G - threshold)) < -knee_dB)
y_G[idx] = x_G[idx]
# At knee
idx = np.where((2 * np.abs(x_G - threshold)) <= knee_dB)
y_G[idx] = x_G[idx] + (
(1 / ratio) * (((x_G[idx] - threshold + knee_dB) / 2) ** 2)
) / (2 * knee_dB)
# Above knee threshold
idx = np.where((2 * (x_G - threshold)) > knee_dB)
y_G[idx] = threshold + ((x_G[idx] - threshold) / ratio)
x_L = x_G - y_G
# this loop is slow but not vectorizable due to its cumulative, sequential nature. @autojit makes it fast(er).
y_L = np.zeros(N, dtype=dtype)
for n in range(1, N):
# smooth over the gainChange
if x_L[n] > y_L[n - 1]: # attack mode
y_L[n] = (alpha_A * y_L[n - 1]) + ((1 - alpha_A) * x_L[n])
else: # release
y_L[n] = (alpha_R * y_L[n - 1]) + ((1 - alpha_R) * x_L[n])
# Convert to linear amplitude scalar; i.e. map from dB to amplitude
lin_y_L = np.power(10.0, (-y_L / 20.0))
y = lin_y_L * x # Apply linear amplitude to input sample
y *= np.power(10.0, makeup_gain_dB / 20.0) # apply makeup gain
return y.astype(dtype)
class Compressor(Processor):
def __init__(
self,
sample_rate,
max_threshold=0.0,
min_threshold=-80,
max_ratio=20.0,
min_ratio=1.0,
max_attack=0.1,
min_attack=0.0001,
max_release=1.0,
min_release=0.005,
max_knee=12.0,
min_knee=0.0,
max_mkgain=48.0,
min_mkgain=-48.0,
eps=1e-8,
):
""" """
super().__init__()
self.sample_rate = sample_rate
self.eps = eps
self.ports = [
{
"name": "Threshold",
"min": min_threshold,
"max": max_threshold,
"default": -12.0,
"units": "",
},
{
"name": "Ratio",
"min": min_ratio,
"max": max_ratio,
"default": 2.0,
"units": "",
},
{
"name": "Attack Time",
"min": min_attack,
"max": max_attack,
"default": 0.001,
"units": "s",
},
{
"name": "Release Time",
"min": min_release,
"max": max_release,
"default": 0.045,
"units": "s",
},
{
"name": "Knee",
"min": min_knee,
"max": max_knee,
"default": 6.0,
"units": "dB",
},
{
"name": "Makeup Gain",
"min": min_mkgain,
"max": max_mkgain,
"default": 0.0,
"units": "dB",
},
]
self.num_control_params = len(self.ports)
self.process_fn = compressor
def forward(self, x, p, sample_rate=24000, **kwargs):
"All processing in the forward is in numpy."
return self.run_series(x, p, sample_rate)