audiolib.py

# -*- coding: utf-8 -*-
"""
@author: chkarada
"""
import os
import numpy as np
import soundfile as sf
import subprocess
import glob
import librosa
import random
import tempfile

EPS = np.finfo(float).eps
np.random.seed(0)

def is_clipped(audio, clipping_threshold=0.99):
    return any(abs(audio) > clipping_threshold)

def normalize(audio, target_level=-25):
    '''Normalize the signal to the target level'''
    rms = (audio ** 2).mean() ** 0.5
    scalar = 10 ** (target_level / 20) / (rms+EPS)
    audio = audio * scalar
    return audio

def normalize_segmental_rms(audio, rms, target_level=-25):
    '''Normalize the signal to the target level
    based on segmental RMS'''
    scalar = 10 ** (target_level / 20) / (rms+EPS)
    audio = audio * scalar
    return audio

def audioread(path, norm=False, start=0, stop=None, target_level=-25):
    '''Function to read audio'''

    path = os.path.abspath(path)
    if not os.path.exists(path):
        raise ValueError("[{}] does not exist!".format(path))
    try:
        audio, sample_rate = sf.read(path, start=start, stop=stop)
    except RuntimeError:  # fix for sph pcm-embedded shortened v2
        print('WARNING: Audio type not supported')

    if len(audio.shape) == 1:  # mono
        if norm:
            rms = (audio ** 2).mean() ** 0.5
            scalar = 10 ** (target_level / 20) / (rms+EPS)
            audio = audio * scalar
    else:  # multi-channel
        audio = audio.T
        audio = audio.sum(axis=0)/audio.shape[0]
        if norm:
            audio = normalize(audio, target_level)

    return audio, sample_rate


def audiowrite(destpath, audio, sample_rate=16000, norm=False, target_level=-25, \
                clipping_threshold=0.99, clip_test=False):
    '''Function to write audio'''

    if clip_test:
        if is_clipped(audio, clipping_threshold=clipping_threshold):
            raise ValueError("Clipping detected in audiowrite()! " + \
                            destpath + " file not written to disk.")

    if norm:
        audio = normalize(audio, target_level)
        max_amp = max(abs(audio))
        if max_amp >= clipping_threshold:
            audio = audio/max_amp * (clipping_threshold-EPS)

    destpath = os.path.abspath(destpath)
    destdir = os.path.dirname(destpath)

    if not os.path.exists(destdir):
        os.makedirs(destdir)

    sf.write(destpath, audio, sample_rate)
    return


def add_reverb(sasxExe, input_wav, filter_file, output_wav):
    ''' Function to add reverb'''
    command_sasx_apply_reverb = "{0} -r {1} \
        -f {2} -o {3}".format(sasxExe, input_wav, filter_file, output_wav)
                                                               
    subprocess.call(command_sasx_apply_reverb)
    return output_wav


def add_clipping(audio, max_thresh_perc=0.8):
    '''Function to add clipping'''
    threshold = max(abs(audio))*max_thresh_perc
    audioclipped = np.clip(audio, -threshold, threshold)
    return audioclipped


def adsp_filter(Adspvqe, nearEndInput, nearEndOutput, farEndInput):

    command_adsp_clean = "{0} --breakOnErrors 0 --sampleRate 16000 --useEchoCancellation 0 \
                    --operatingMode 2 --useDigitalAgcNearend 0 --useDigitalAgcFarend 0 \
                    --useVirtualAGC 0 --useComfortNoiseGenerator 0 --useAnalogAutomaticGainControl 0 \
                    --useNoiseReduction 0 --loopbackInputFile {1} --farEndInputFile {2} \
                    --nearEndInputFile {3} --nearEndOutputFile {4}".format(Adspvqe,
                                farEndInput, farEndInput, nearEndInput, nearEndOutput)
    subprocess.call(command_adsp_clean)


def snr_mixer(params, clean, noise, snr, target_level=-25, clipping_threshold=0.99):
    '''Function to mix clean speech and noise at various SNR levels'''
    cfg = params['cfg']
    if len(clean) > len(noise):
        noise = np.append(noise, np.zeros(len(clean)-len(noise)))
    else:
        clean = np.append(clean, np.zeros(len(noise)-len(clean)))

    # Normalizing to -25 dB FS
    clean = clean/(max(abs(clean))+EPS)
    clean = normalize(clean, target_level)
    rmsclean = (clean**2).mean()**0.5

    noise = noise/(max(abs(noise))+EPS)
    noise = normalize(noise, target_level)
    rmsnoise = (noise**2).mean()**0.5

    # Set the noise level for a given SNR
    noisescalar = rmsclean / (10**(snr/20)) / (rmsnoise+EPS)
    noisenewlevel = noise * noisescalar

    # Mix noise and clean speech
    noisyspeech = clean + noisenewlevel
    
    # Randomly select RMS value between -15 dBFS and -35 dBFS and normalize noisyspeech with that value
    # There is a chance of clipping that might happen with very less probability, which is not a major issue. 
    noisy_rms_level = np.random.randint(params['target_level_lower'], params['target_level_upper'])
    rmsnoisy = (noisyspeech**2).mean()**0.5
    scalarnoisy = 10 ** (noisy_rms_level / 20) / (rmsnoisy+EPS)
    noisyspeech = noisyspeech * scalarnoisy
    clean = clean * scalarnoisy
    noisenewlevel = noisenewlevel * scalarnoisy

    # Final check to see if there are any amplitudes exceeding +/- 1. If so, normalize all the signals accordingly
    if is_clipped(noisyspeech):
        noisyspeech_maxamplevel = max(abs(noisyspeech))/(clipping_threshold-EPS)
        noisyspeech = noisyspeech/noisyspeech_maxamplevel
        clean = clean/noisyspeech_maxamplevel
        noisenewlevel = noisenewlevel/noisyspeech_maxamplevel
        noisy_rms_level = int(20*np.log10(scalarnoisy/noisyspeech_maxamplevel*(rmsnoisy+EPS)))

    return clean, noisenewlevel, noisyspeech, noisy_rms_level


def segmental_snr_mixer(params, clean, noise, snr, target_level=-25, clipping_threshold=0.99):
    '''Function to mix clean speech and noise at various segmental SNR levels'''
    cfg = params['cfg']
    if len(clean) > len(noise):
        noise = np.append(noise, np.zeros(len(clean)-len(noise)))
    else:
        clean = np.append(clean, np.zeros(len(noise)-len(clean)))
    clean = clean/(max(abs(clean))+EPS)
    noise = noise/(max(abs(noise))+EPS)
    rmsclean, rmsnoise = active_rms(clean=clean, noise=noise)
    clean = normalize_segmental_rms(clean, rms=rmsclean, target_level=target_level)
    noise = normalize_segmental_rms(noise, rms=rmsnoise, target_level=target_level)
    # Set the noise level for a given SNR
    noisescalar = rmsclean / (10**(snr/20)) / (rmsnoise+EPS)
    noisenewlevel = noise * noisescalar

    # Mix noise and clean speech
    noisyspeech = clean + noisenewlevel
    # Randomly select RMS value between -15 dBFS and -35 dBFS and normalize noisyspeech with that value
    # There is a chance of clipping that might happen with very less probability, which is not a major issue. 
    noisy_rms_level = np.random.randint(params['target_level_lower'], params['target_level_upper'])
    rmsnoisy = (noisyspeech**2).mean()**0.5
    scalarnoisy = 10 ** (noisy_rms_level / 20) / (rmsnoisy+EPS)
    noisyspeech = noisyspeech * scalarnoisy
    clean = clean * scalarnoisy
    noisenewlevel = noisenewlevel * scalarnoisy
    # Final check to see if there are any amplitudes exceeding +/- 1. If so, normalize all the signals accordingly
    if is_clipped(noisyspeech):
        noisyspeech_maxamplevel = max(abs(noisyspeech))/(clipping_threshold-EPS)
        noisyspeech = noisyspeech/noisyspeech_maxamplevel
        clean = clean/noisyspeech_maxamplevel
        noisenewlevel = noisenewlevel/noisyspeech_maxamplevel
        noisy_rms_level = int(20*np.log10(scalarnoisy/noisyspeech_maxamplevel*(rmsnoisy+EPS)))

    return clean, noisenewlevel, noisyspeech, noisy_rms_level
    

def active_rms(clean, noise, fs=16000, energy_thresh=-50):
    '''Returns the clean and noise RMS of the noise calculated only in the active portions'''
    window_size = 100 # in ms
    window_samples = int(fs*window_size/1000)
    sample_start = 0
    noise_active_segs = []
    clean_active_segs = []

    while sample_start < len(noise):
        sample_end = min(sample_start + window_samples, len(noise))
        noise_win = noise[sample_start:sample_end]
        clean_win = clean[sample_start:sample_end]
        noise_seg_rms = 20*np.log10((noise_win**2).mean()+EPS)
        # Considering frames with energy
        if noise_seg_rms > energy_thresh:
            noise_active_segs = np.append(noise_active_segs, noise_win)
            clean_active_segs = np.append(clean_active_segs, clean_win)
        sample_start += window_samples

    if len(noise_active_segs)!=0:
        noise_rms = (noise_active_segs**2).mean()**0.5
    else:
        noise_rms = EPS
        
    if len(clean_active_segs)!=0:
        clean_rms = (clean_active_segs**2).mean()**0.5
    else:
        clean_rms = EPS

    return clean_rms, noise_rms


def activitydetector(audio, fs=16000, energy_thresh=0.13, target_level=-25):
    '''Return the percentage of the time the audio signal is above an energy threshold'''

    audio = normalize(audio, target_level)
    window_size = 50 # in ms
    window_samples = int(fs*window_size/1000)
    sample_start = 0
    cnt = 0
    prev_energy_prob = 0
    active_frames = 0

    a = -1
    b = 0.2
    alpha_rel = 0.05
    alpha_att = 0.8

    while sample_start < len(audio):
        sample_end = min(sample_start + window_samples, len(audio))
        audio_win = audio[sample_start:sample_end]
        frame_rms = 20*np.log10(sum(audio_win**2)+EPS)
        frame_energy_prob = 1./(1+np.exp(-(a+b*frame_rms)))

        if frame_energy_prob > prev_energy_prob:
            smoothed_energy_prob = frame_energy_prob*alpha_att + prev_energy_prob*(1-alpha_att)
        else:
            smoothed_energy_prob = frame_energy_prob*alpha_rel + prev_energy_prob*(1-alpha_rel)

        if smoothed_energy_prob > energy_thresh:
            active_frames += 1
        prev_energy_prob = frame_energy_prob
        sample_start += window_samples
        cnt += 1

    perc_active = active_frames/cnt
    return perc_active


def resampler(input_dir, target_sr=16000, ext='*.wav'):
    '''Resamples the audio files in input_dir to target_sr'''
    files = glob.glob(f"{input_dir}/"+ext)
    for pathname in files:
        print(pathname)
        try:
            audio, fs = audioread(pathname)
            audio_resampled = librosa.core.resample(audio, fs, target_sr)
            audiowrite(pathname, audio_resampled, target_sr)
        except:
            continue


def audio_segmenter(input_dir, dest_dir, segment_len=10, ext='*.wav'):
    '''Segments the audio clips in dir to segment_len in secs'''
    files = glob.glob(f"{input_dir}/"+ext)
    for i in range(len(files)):
        audio, fs = audioread(files[i])
        
        if len(audio) > (segment_len*fs) and len(audio)%(segment_len*fs) != 0:
            audio = np.append(audio, audio[0 : segment_len*fs - (len(audio)%(segment_len*fs))]) 
        if len(audio) < (segment_len*fs):
            while len(audio) < (segment_len*fs):
                audio = np.append(audio, audio)
            audio = audio[:segment_len*fs]
        
        num_segments = int(len(audio)/(segment_len*fs))
        audio_segments = np.split(audio, num_segments)

        basefilename = os.path.basename(files[i])
        basename, ext = os.path.splitext(basefilename)

        for j in range(len(audio_segments)):
            newname = basename+'_'+str(j)+ext
            destpath = os.path.join(dest_dir,newname)
            audiowrite(destpath, audio_segments[j], fs)