Ndtyjky

I'm giving my code with few audio files which are not giving appropriate output.
Code:

import numpy as np

import math

import wave

import os

import struct



def note_detect(audio_file):



    Detected_Note = ""



    beta = 1   

    max_notes = 100   

    sampling_freq = 38050 

    window_size = (sampling_freq / 37)   

    threshold = 600

    array = [440.00, 130.8, 329.6, 196]



    notes = ['A4', 'C3', 'E4', 'G3' ]

    Identified_Notes = 

    file_length = audio_file.getnframes()

    sound = np.zeros(file_length)

    for i in range(file_length):

        data = audio_file.readframes(1)

        data = struct.unpack("<h", data)

        sound[i] = int(data[0])

    sound = np.divide(sound, float(2**15))



    sound_square = np.square(sound)

    frequency = 

    dft = 

    i = 0

    j = 0

    k = 0

    while(i<=len(sound_square)-window_size):

        s = 0.0

        j = 0

        while(j<=window_size):

            s = s + sound_square[i+j]

            j = j + 1

        if s < threshold:

            if(i-k>window_size*4):

                dft = np.array(dft)

                dft = np.fft(sound[k:i])



                dft=np.argsort(dft)



                if(dft[0]>dft[-1] and dft[1]>dft[-1]):

                    i_max = dft[-1]

                elif(dft[1]>dft[0] and dft[-1]>dft[0]):

                    i_max = dft[0]

                else :

                    i_max = dft[1]



                frequency.append((i_max*sampling_freq)/(i-k))

                dft = 

                k = i+1

        i = i + window_size



    print('length',len(frequency))

    print("frequency")



    for i in frequency :

        print(i)

        idx = (np.abs(array-i)).argmin()

        Identified_Notes.append(notes[idx])

    print(Identified_Notes)

    Detected_Note=max(Identified_Notes,key=Identified_Notes.count)      

    return Detected_Note







if __name__ == "__main__":





    path = os.getcwd()



    file_name = path + "Task_1.1_Audio_filesAudio_4.wav"

    audio_file = wave.open(file_name)



    Detected_Note = note_detect(audio_file)



    print("ntDetected Note = " + str(Detected_Note))





    x = raw_input("ntWant to check output for all Audio Files - Y/N: ")



    if x == 'Y':



        Detected_Note_list = 



        file_count = len(os.listdir(path + "Task_1.1_Audio_files"))



        for file_number in range(1, file_count):



            file_name = path + "Task_1.1_Audio_filesAudio_"+str(file_number)+".wav"

            audio_file = wave.open(file_name)



            Detected_Note = note_detect(audio_file)



            Detected_Note_list.append(Detected_Note)



        print("ntDetected Notes = " + str(Detected_Note_list))

Audio files link:
https://drive.google.com/open?id=1KVEQQUqBvwgDPf2JC_uQ0L6M_gzGDG6l

Respective output for Audio_6.wav is A4, for Audio_4.wav is E4,for Audio_5.wav is G3

it's probably because you're using a custom rectangular window, try blackmanharris from scipy.signal and use np.argmax for calculating i_max.
I checked the audio files and they only have 1 frequency but you're calculating 4 from your algorithm and then taking the highest one.
I've adjusted the code take a look but the Audio_4.wav file is still showing the note E5 on my side that is probably the note you gave could be wrong, can you get it checked?

def matching_freq(freq):

    note=""

    if(freq>15 and freq<17.32):

        note= "C0"

        return note

    elif(freq>17.32 and freq<19.45):

        note="D0"

        return note

    elif(freq>19.45 and freq<20.8):

        note="E0"

        return note

    elif(freq>20.8 and freq<23.12):

        note="F0"

        return note

    elif(freq>23.12 and freq<25.96):

        note="G0"

        return note

    elif(freq>25.96 and freq<29.14):

        note="A0"

        return note

    elif(freq>29.14 and freq<31):

        note="B0"

        return note

    elif(freq>31 and freq<34.65):

        note="C1"

        return note

    elif(freq>34.65 and freq<38.89):

        note="D1"

        return note

    elif(freq>38.89 and freq<42):

        note="E1"

        return note

    elif(freq>42 and freq<46.25):

        note="F1"

        return note

    elif(freq>46.25 and freq<51.91):

        note="G1"

        return note

    elif(freq>51.91 and freq<58.27):

        note="A1"

        return note

    elif(freq>58.27 and freq<63):

        note="B1"

        return note

    elif(freq>63 and freq<69.30):

        note="C2"

        return note

    elif(freq>69.30 and freq<77.78):

        note="D2"

        return note

    elif(freq>77.78 and freq<85):

        note="E2"

        return note

    elif(freq>85 and freq<92.50):

        note="F2"

        return note

    elif(freq>92.50 and freq<103.83):

        note="G2"

        return note

    elif(freq>103.83 and freq<116.54):

        note="A2"

        return note

    elif(freq>116.54 and freq<126):

        note="B2"

        return note

    elif(freq>126 and freq<138.59):

        note="C3"

        return note

    elif(freq>138.59 and freq<155.56):

        note="D3"

        return note

    elif(freq>155.56 and freq<168):

        note="E3"

        return note

    elif(freq>168 and freq<185):

        note="F3"

        return note

    elif(freq>185 and freq<207.65):

        note="G3"

        return note

    elif(freq>207.65 and freq<233.08):

        note="A3"

        return note

    elif(freq>233.08 and freq<253):

        note="B3"

        return note

    elif(freq>253 and freq<277.18):

        note="C4"

        return note

    elif(freq>277.18 and freq<311.13):

        note="D4"

        return note

    elif(freq>311.13 and freq<338):

        note="E4"

        return note

    elif(freq>338 and freq<369.99):

        note="F4"

        return note

    elif(freq>369.99 and freq<415.3):

        note="G4"

        return note

    elif(freq>415.3 and freq<466.16):

        note="A4"

        return note

    elif(freq>466.16 and freq<500):

        note="B4"

        return note

    elif(freq>500 and freq<554.37):

        note="C5"

        return note

    elif(freq>554.37 and freq<622.25):

        note="D5"

        return note

    elif(freq>622.25 and freq<675):

        note="E5"

        return note

    elif(freq>675 and freq<740):

        note="F5"

        return note

    elif(freq>740 and freq<830):

        note="G5"

        return note

    elif(freq>830 and freq<932):

        note="A5"

        return note

    elif(freq>932 and freq<1000):

        note="B5"

        return note

    elif(freq>1000 and freq<1108):

        note="C6"

        return note

    elif(freq>1108 and freq<1244):

        note="D6"

        return note

    elif(freq>1244 and freq<1350):

        note="E6"

        return note

    elif(freq>1350 and freq<1480):

        note="F6"

        return note

    elif(freq>1480 and freq<1661.22):

        note="G6"

        return note

    elif(freq>1661.22 and freq<1864):

        note="A6"

        return note

    elif(freq>1864 and freq<2000):

        note="B6"

        return note

    elif(freq>2000 and freq<2217.46):

        note="C7"

        return note

    elif(freq>2217.46 and freq<2489.02):

        note="D7"

        return note

    elif(freq>2489.02 and freq<2700):

        note="E7"

        return note

    elif(freq>2700 and freq<2960):

        note="F7"

        return note

    elif(freq>2960 and freq<3322.4):

        note="G7"

        return note

    elif(freq>3322.4 and freq<3729):

        note="A7"

        return note

    elif(freq>3729.31 and freq<4040):

        note="B7"

        return note

    elif(freq>4040 and freq<4435):

        note="C8"

        return note

    elif(freq>4435 and freq<4978):

        note="D8"

        return note

    elif(freq>4978 and freq<5350):

        note="E8"

        return note

    elif(freq>5350 and freq<5919):

        note="F8"

        return note

    elif(freq>5919 and freq<6644):

        note="G8"

        return note

    elif(freq>6644 and freq<7458):

        note="A8"

        return note

    elif(freq>7458 and freq<8000):

        note="B8"

        return note





def note_detect(audio_file):

Detected_Note = 

length = audio_file.getnframes()

sound  = np.zeros(length)



for i in range(length):

    data = audio_file.readframes(1)

    data = struct.unpack("<h", data)

    sound[i] = int(data[0])



sound = np.divide(sound, float(2**15))

window = sound * np.blackmanharris(len(sound))

f = np.fft.fft(window)

i_max = np.argmax(abs(f))

print(i_max)

freq = (i_max * fs)/len(sound)

print(freq)

Detected_Note = matching_freq(freq)

return Detected_Note`