Merge branch 'main' into alex

src/DarellAnnePitchEnvelope.m

@@ -0,0 +1,57 @@
+%Written by Darell and Anne
+
+function output = DarellAnnePitchEnvelope(input, Fs, attack,decay,sustain,release) %percentages for attack, decay, sustain, release
+    len = length(input);
+    T = (len-1)/Fs;
+    attacktime = attack * T * Fs;
+    decaytime = attacktime + decay * T * Fs;
+    sustaintime = (T - (release * T)) * Fs;
+    
+    output =  zeros([1,len]); 
+    
+    tcounter = 1;
+    %attack phase
+    curr = attacktime;
+    while tcounter <= curr
+        ncount = round(curr*log(tcounter)/log(curr)+1);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+    
+    %decay phase
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = decaytime;
+    while tcounter <= curr
+        ncount = round(sustain*curr*(1-log(tcounter)/log(prevcur)) + prevcur);
+        tcounter = round(tcounter);
+        output(tcounter)
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+    
+    %sustain phase
+    prevncount = ncount;
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = sustaintime;
+    while tcounter <= curr
+        ncount = round(sustain*(tcounter - prevcur) + prevncount);
+        tcounter = round(tcounter);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+
+    %release phase
+    prevncount = ncount;
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = Fs;
+    while tcounter <= Fs
+        ncount = round(curr*(1-log(tcounter)/log(prevcur)) + prevncount);
+        tcounter = round(tcounter);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+
+end

src/FilterSelect.m

@@ -0,0 +1,10 @@
+function output = FilterSelect(input,Fs,LOW,MED,HIGH,number)
+    if(number == "Option 1")
+        output = DarellbandpassFilter(input,Fs,LOW,MED,HIGH);
+    elseif(number == "Option 2")
+        output = amplifyFreqRange(input, Fs, LOW, MED, HIGH);
+    else
+        output = input;
+    end
+end 
+

src/Main_test.m

@@ -13,7 +13,7 @@ x = x + generate_sine(amplitude, (frequency+5), phase, fs, duration, duty);
 
 %play over 5 counts, should hear both frequencies, 5 beats per second between the 2 frequencies
 playtime = 5;
-play_continuous(x, fs, playtime)
+%play_continuous(x, fs, playtime)
 
 LOW = 0;
 HIGH = frequency + 1;
@@ -22,7 +22,14 @@ x = DarellbandpassFilter(x,fs,LOW,MED,HIGH);
 
 %play over 5 counts, should only hear 200hz
 playtime = 5;
-play_continuous(x, fs, playtime)
+%play_continuous(x, fs, playtime)
+
+attack = 0.2;
+decay = 0.1;
+sustain = 0.8;
+release = 0.4;
+
+x = DarellAnnePitchEnvelope(x, Fs, attack,decay,sustain,release);
 
 attack = 0.2;
 decay = 0.2;

src/PitchEnvelopeSelect.m

@@ -1,6 +1,6 @@
 function output = PitchEnvelopeSelect(input, Fs, attack,decay,sustain,release,number)
     if(number == "Option 1")
-        output = DarellAmplitudeEnvelope(input, Fs, attack,decay,sustain,release);
+        output = DarellAnnePitchEnvelope(input, Fs, attack,decay,sustain,release);
     else
         output = input;
     end

src/SoundGeneratorSelect.m

@@ -5,7 +5,10 @@ function output = SoundGeneratorSelect(amplitude, frequency, phase, fs, duration
         output = generate_square(amplitude, frequency, phase, fs, duration, duty);
     elseif(number == "Option 3")
         output = generate_triangle(amplitude, frequency, phase, fs, duration, duty);
-    
+    elseif(number == "Option 4")
+        output = generate_sawtooth(amplitude, frequency, phase, fs, duration, duty);
+    elseif(number == "Option 5")
+        output = generate_white(amplitude, frequency, phase, fs, duration, duty);
     else
         output = 0;
     end

src/bandreject_filter.m

@@ -0,0 +1,62 @@
+function output_y = bandreject_filter(Input, Fs, Low, High)
+    % A filter that lets through most frequencies unaltered
+    % but attentuates the frequencies in the specified range to
+    % very low levels
+    % (basically exliminates them)
+    % By Yalu Ouyang
+    
+
+    % Input: the input signal in the time domain
+    % Fs: the sampling frequency
+    % Low: the lower limit of the specified range
+    % High: the upper limit of the specified range
+    % Returns Output: the filtered signal in the time domain
+
+    len = length(Input);
+    
+    F = Fs * (-len/2 : (len/2 - 1)) / len ;
+    
+    % modified signal in the frequency domain
+    % using Fourier Transform
+    mod_freq = fftshift(fft(Input));
+    
+    len_f = length(mod_freq);
+    
+    % use this array to record the frequencies
+    % that should pass through
+    % 0 indicates reject
+    % 1 indicates pass
+    multiplier =  zeros([1,len_f]); 
+    
+    for index = 1 : len_f
+
+        % within range of band reject
+        % so elminate these frequencies
+        if ((Low < abs(F(index))) && (abs(F(index)) < High))
+            multiplier(index) = 0;
+        
+        % outside of specified range
+        % so shoudln't be altered
+        else
+            multiplier(index) = 1;
+        end
+    end
+    
+    % filtered signal in the frequency domain
+    filtered_mod_freq = fftshift(mod_freq .* multiplier);
+    
+    % convert signal back to the time domain
+    Output = real(ifft(filtered_mod_freq));
+    
+end
+
+% This function is useful for eliminating
+% unwanted signals that have frequencies close to the 
+% median frequency of the original signal
+% (consider overall frequencies as one part, 
+% this elminates the middle portion)
+
+% Fourier transform is applied in this function
+% to make it easier to eliminate specified 
+% frequencies of the signal
+% (easier to do so in the frequency domain)

src/epic_effect_schluep.m

@@ -0,0 +1,55 @@
+function output = epic_effect_schluep(input, Fs, LOW, MED, HIGH)
+% epic_effect_schluep: Outputs a more "epic" version of the input sound.
+% This is done by amplifying low frequencies and by implementing a chorus
+% effect. A chorus effect is created when multiple copies of sound delayed
+% by a small, random amount are added to the original signal. Works best on
+% songs with a stronger bassline.
+% Try this function out with "Strong_Bassline.mp3".
+
+% CONTRIBUTORS:
+% Nicolas Schluep: Function Author
+
+% DOCUMENTATION:
+% input: The input sound in the time-domain.
+% Fs: The sampling rate of the input signal. A typical value is 44100 Hz.
+% HIGH: The maximum frequency the filter will amplify. A typical value for 
+% this variable is 1000 Hz.
+
+non_stereophonic = input(:, 1);     % Removes the sterophonic property of the input sound
+% by just taking the first column of data.
+
+Len = length(non_stereophonic);
+F = Fs * ((-Len/2) : ((Len/2) - 1)) / Len;  % Creating the array of frequencies
+% which the FFT Shifted version of the signal can be plotted against.
+inputFreq = fftshift(fft(non_stereophonic));   % Creates the Fourier Transform of the
+% input signal. fftshift() makes it such that the zero frequency is at the 
+% center of the array.
+lowAmplifyFilter = zeros(1, length(inputFreq));
+
+% Creating a filter which amplifies lower frequencies.
+for i = 1:length(lowAmplifyFilter)
+    if abs(F(i)) < HIGH
+        lowAmplifyFilter(i) = 1.25;
+    else
+        lowAmplifyFilter(i) = 1.00;
+    end
+end
+
+lowPassedInput = inputFreq .* transpose(lowAmplifyFilter); %Apply the "lowAmplifyFilter".
+
+% Adding the chorus effect.
+realOutput = real(ifft(fftshift(lowPassedInput)));
+output = realOutput;
+
+% Adding 100 randomly delayed signals to the original signal which creates the chorus effect.
+for i = 1:100
+    currentDelay = 0.003 * rand();  % The current delay of the sound in seconds.
+    currentIndex = round(currentDelay * Fs);    % Find the first index where the sound should start playing.
+    delayedOutput = [zeros(currentIndex, 1); realOutput];      % Adds "currentIndex" zeros to the front of the 
+    % "realOutput" vector to create a slightly delayed version of the signal.
+    delayedOutput = delayedOutput(1:length(realOutput));    % Truncates the "delayedOutput"
+    % vector so that it can be added to the "realOutput" vector.
+    output = output + delayedOutput; 
+end
+
+output = output ./ 100;     % Divide by 100 to decrease the amplitude of the sound to a normal level.

src/fade_in.m

@@ -0,0 +1,29 @@
+function output = fade_in(input, time)
+    % Creates a fade-in sound effect that lasts a given
+    % time parameter of the input sound signal
+    % By Yalu Ouyang
+    
+
+    % input: a 1D array that represents the sound signal in the time domain
+    % time: how long the fade in effect should last
+    % Shouldn't be longer than the input signal (in which case the function
+    % treats it as the duration of the signal)
+    % Returns modified signal in the time domain (output).
+    
+    len = length(input);
+    
+    % if time parameter longer than signal, treat time as
+    % the duration of original signal
+    if time > len
+        time = len
+    end
+
+    % set multiplier as 1D array
+    % fade in effect: from no volume to full volume of signal
+    multiplier = (1 : time) / time;
+
+    % the resulting fade-in output  
+    output = input .* multiplier;
+end
+
+% This is useful for making videos, specifically the intro part 

src/fade_out.m

@@ -0,0 +1,32 @@
+function output = fade_out(input, time)
+    % Creates a fade-out sound effect that lasts a given
+    % time parameter of the input sound signal
+    % By Yalu Ouyang
+    
+    % input: a 1D array that represents the sound signal in the time domain
+    % time: how long the fade out effect should last
+    % Shouldn't be longer than the input signal 
+    % (in which case the function treats it as the duration of the signal)
+    % Returns modified signal in the time domain (output).
+    
+    len = length(input);
+    
+    % if time parameter longer than signal, treat time as
+    % the duration of original signal
+    if time > len
+        time = len
+    end
+
+    % set multiplier as 1D array
+
+    multiplier = (1 : time) / time;
+
+    % fade out effect: from full volume of signal to no volume
+    multiplier = flip(multiplier)
+
+    % the resulting fade-in output  
+    output = input .* multiplier;
+end
+
+
+% This is useful for creating videos, specifically the outro part

src/muffled_effect_schluep.m

@@ -0,0 +1,56 @@
+function output = muffled_effect_schluep(input, Fs, LOW, MED, HIGH)
+% muffled_effect_schluep: Outputs a muffled version of the the original input
+% sound in the time domain. This makes it sound as if the audio is being 
+% played in another room.
+% Try this function out with "Strong_Bassline.mp3".
+
+% CONTRIBUTORS:
+% Nicolas Schluep: Function Author
+
+% DOCUMENTATION:
+% input: The input sound in the time-domain.
+% Fs: The sampling rate of the input signal. A typical value is 44100 Hz.
+% HIGH: The maximum frequency that the low-pass filter will let pass. A
+% typical value for this variable is 1000 Hz.
+
+non_stereophonic = input(:, 1);     % Removes the sterophonic property of the input sound
+% by just taking the first column of data.
+
+Len = length(non_stereophonic);
+F = Fs * ((-Len/2) : ((Len/2) - 1)) / Len;  % Creating the array of frequencies
+% which the FFT Shifted version of the signal can be plotted against.
+inputFreq = fftshift(fft(non_stereophonic));   % Creates the Fourier Transform of the
+% input signal. fftshift() makes it such that the zero frequency is at the 
+% center of the array.
+lowPassFilter = zeros(1, length(inputFreq));
+
+% Creating Low Pass Filter
+for i = 1:length(lowPassFilter)
+    if abs(F(i)) < HIGH
+        lowPassFilter(i) = 1;
+    else
+        lowPassFilter(i) = 0;
+    end
+end
+
+lowPassedInput = inputFreq .* transpose(lowPassFilter); %Apply the low-pass filter.
+
+% Adding a slight reverb effect.
+realOutput = real(ifft(fftshift(lowPassedInput)));
+
+delay = 0.001;     % The delay of the sound in seconds.
+index = round(delay*Fs);    % Find the first index where sound should start playing
+% by multiplying the delay by the sampling frequency.
+delayedOutput = [zeros(index, 1); realOutput];      % Adds "index" zeros to the front of the 
+% "realOutput" vector to create a slightly delayed version of the signal.
+delayedOutput = delayedOutput(1:length(realOutput));    % Truncates the "delayedOutput"
+% vector so that it can be added to the "realOutput" vector.
+
+output = (realOutput + delayedOutput) ./ 2.0;    % Adds the "realOutput" and "delayedOutput"
+% vectors to create a reverb effect. Divides by 2 to avoid clipping
+% effects.
+
+
+
+
+

src/seperate_prevalent_schluep.m

@@ -0,0 +1,62 @@
+function output = seperate_prevalent_schluep(input, Fs, LOW, MED, HIGH)
+% seperate_prevalent_schluep: Attempts to seperate the most prevalent frequencies
+% from the input sound by finding the most prevalent frequencies and applying
+% a band-pass filter to a small region around those frequencies.
+% Try this function out with "Strong_Bassline.mp3".
+
+% CONTRIBUTORS:
+% Nicolas Schluep: Function Author
+
+% DOCUMENTATION:
+% input: The input sound in the time-domain.
+% Fs: The sampling rate of the input signal. A typical value is 44100 Hz.
+% HIGH: The maximum distance around the maximum frequency value that will
+% not be attenuated. A good range of values is usually 250-500 Hz, but it
+% depends on the input sound.
+
+non_stereophonic = input(:, 1);     % Removes the sterophonic property of the input sound
+% by just taking the first column of data.
+
+Len = length(non_stereophonic);
+F = Fs * ((-Len/2) : ((Len/2) - 1)) / Len;  % Creating the array of frequencies
+% which the FFT Shifted version of the signal can be plotted against.
+inputFreq = fftshift(fft(non_stereophonic));   % Creates the Fourier Transform of the
+% input signal. fftshift() makes it such that the zero frequency is at the 
+% center of the array.
+bandPassFilter = zeros(1, length(inputFreq));
+
+maxAmplitude = 0;
+mostPrevalentFrequency = 0;
+
+% Finding the most prevalent frequency.
+for i = round(length(inputFreq)/2):length(inputFreq)
+    if inputFreq(i) > maxAmplitude
+        maxAmplitude = inputFreq(i);
+        mostPrevalentFrequency = F(i);
+    end
+end
+
+% Determining maximum and minimum frequency values for the Band Pass filter.
+maxFrequency = mostPrevalentFrequency + HIGH;
+minFrequency = mostPrevalentFrequency - HIGH;
+
+if minFrequency < 0.0
+    minFrequency = 0.0;
+end
+
+% Creating the Band-Pass filter.
+for i = 1:length(bandPassFilter)
+    if (abs(F(i)) < maxFrequency) && (abs(F(i)) > minFrequency)
+        bandPassFilter(i) = 1;
+    else
+        bandPassFilter(i) = 0;
+    end
+end
+
+bandPassedInput = inputFreq .* transpose(bandPassFilter); %Apply the Band-Pass Filter.
+
+output = real(ifft(fftshift(bandPassedInput)));
+
+
+
+