diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..21229f7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.asv
\ No newline at end of file
diff --git a/Level_1/AACoder1.m b/Level_1/AACoder1.m
index d3de782..0926305 100644
--- a/Level_1/AACoder1.m
+++ b/Level_1/AACoder1.m
@@ -1,5 +1,5 @@
 function AACSeq1 = AACoder1(fNameIn)
-%Implementation of WHAT?? //TODO!!
+%Implementation of AAC encoder
 %   Usage AACSeq1 = AACoder1(fNameIn), where:
 %       Inputs
 %       - fNameIn is the filename and path of the file to encode
@@ -32,11 +32,12 @@ function AACSeq1 = AACoder1(fNameIn)
         frameTypes{length(frameTypes)} = 'OLS';
     end
 
+    % Encodes audio file
     AACSeq1(length(frameTypes)) = struct;
     for i = 0:length(frameTypes)-1
         currFrameStart = i * 1024 + 1;
         currFrameStop = currFrameStart + 2047;
-        frameF = filterbank(originalAudioData(currFrameStart:currFrameStop, :), frameTypes{i+1}, 'SIN');
+        frameF = filterbank(originalAudioData(currFrameStart:currFrameStop, :), frameTypes{i+1}, 'KBD');
 
         AACSeq1(i + 1).frameType = frameTypes(i + 1);
         AACSeq1(i + 1).winType = 'KBD';
@@ -44,7 +45,7 @@ function AACSeq1 = AACoder1(fNameIn)
         AACSeq1(i + 1).chr.frameF = frameF(:, 2);
     end
 
-    if true
+    if false
         [idx,label] = grp2idx(sort(frameTypes));
         hist(idx,unique(idx));
         set(gca,'xTickLabel',label)
diff --git a/Level_1/SSC.m b/Level_1/SSC.m
index db5d485..058c656 100644
--- a/Level_1/SSC.m
+++ b/Level_1/SSC.m
@@ -1,5 +1,5 @@
 function frameType = SSC(~, nextFrameT, prevFrameType)
-%Implementation of the SSC step
+%Implementation of the Sequence Segmentation Control step
 %   Usage frameType = SSC(frameT, nextFrameT, prevFrameType), where:
 %       Inputs
 %       - frameT is a frame in the time domain, containing both channels of
@@ -29,29 +29,29 @@ function frameType = SSC(~, nextFrameT, prevFrameType)
 
     % Determines the type of the next frame
     % Filters frame
-    nextFrameT = filter([0.7548, -0.7548], [1, -0.5095], nextFrameT, [], 2);
+    nextFrameT = filter([0.7548, -0.7548], [1, -0.5095], nextFrameT, [], 1);
 
-    channelFrameType = {'OLS', 'OLS'};
+    channelFrameType = {'nan', 'nan'};
 
     for channel = 1:2
         % Calculates sub-frame energy estimation
-        [subFrames, ~] = buffer(nextFrameT(449:end-448, channel), 256, 128, 'nodelay');
-        energyEstimations = sum(subFrames.^2, 1);
+        [subFrames, ~] = buffer(nextFrameT(449:end - 448, channel), 256, 128, 'nodelay');
+        energyEstimations = sum(subFrames .^ 2, 1);
 
         % Calculates the ratio of the sub-frame energy to the average energy of
         % the previous sub-frames
-        nextIsESH = 0;
-        for subFrameIndex = 1:8
+        nextIsESH = false;
+        for subFrameIndex = 2:8
             energyRatio = energyEstimations(subFrameIndex) / ...
-                mean(energyEstimations(1:subFrameIndex-1));
+                mean(energyEstimations(1:subFrameIndex - 1));
 
             if (energyEstimations(subFrameIndex) > 10^(-3)) && (energyRatio > 10)
-                nextIsESH = 1;
+                nextIsESH = true;
                 break;
             end
         end
 
-        if nextIsESH == 1
+        if nextIsESH == true
             if strcmp(prevFrameType, 'ESH')
                 % This frame of this channel is an EIGHT_SHORT_SEQUENCE type
                 % frame. This means the frames of both channels will be encoded
@@ -70,6 +70,9 @@ function frameType = SSC(~, nextFrameT, prevFrameType)
         end
     end
 
+    if strcmp(channelFrameType{1}, 'nan') || strcmp(channelFrameType{2}, 'nan')
+        error('SSC, l[73]: Internal error occured!')
+    end
     if strcmp(channelFrameType{1}, 'OLS')
         frameType = channelFrameType{2};
     elseif strcmp(channelFrameType{2}, 'OLS')
diff --git a/Level_1/decoded2.wav b/Level_1/decoded2.wav
new file mode 100644
index 0000000..374d997
Binary files /dev/null and b/Level_1/decoded2.wav differ
diff --git a/Level_1/demoAAC1.m b/Level_1/demoAAC1.m
index 38cba32..21fec1b 100644
--- a/Level_1/demoAAC1.m
+++ b/Level_1/demoAAC1.m
@@ -14,6 +14,14 @@ function SNR = demoAAC1(fNameIn, fNameOut)
     decodedAudio = iAACoder1(AACSeq1, fNameOut);
 
     [audioData, ~] = audioread(fNameIn);
-    SNR = sum(10*log10((sum(audioData(1:length(decodedAudio), :)) .^ 2)./ ...
-        (sum(audioData(1:length(decodedAudio), :) - decodedAudio) .^ 2)));
+    
+    figure()
+    plot(audioData(1:length(decodedAudio), 1) - decodedAudio(1:end, 1))
+    figure()
+    plot(audioData(1:length(decodedAudio), 2) - decodedAudio(1:end, 2))
+    
+    snr(audioData(1:length(decodedAudio), 1), audioData(1:length(decodedAudio), 1) - decodedAudio(1:end, 1))
+    snr(audioData(1:length(decodedAudio), 2), audioData(1:length(decodedAudio), 2) - decodedAudio(1:end, 2))
+    SNR = 10*log10((sum(audioData(1:length(decodedAudio), :)) .^ 2) ./ ...
+        (sum(audioData(1:length(decodedAudio), :) - decodedAudio) .^ 2));
 end
diff --git a/Level_1/filterbank.m b/Level_1/filterbank.m
index f1a1f7b..98fea67 100644
--- a/Level_1/filterbank.m
+++ b/Level_1/filterbank.m
@@ -56,7 +56,7 @@ function frameF = filterbank(frameT, frameType, winType)
                 error('filterbank, l[20]: Unsupported window type input!')
             end
 
-            frameF = mdct4(frameT);
+            frameF(:, channel) = mdct4(frameT(:, channel));
         elseif strcmp(frameType, 'LSS')
             if strcmp(winType, 'KBD')
                 frameT(1:1024, channel) = frameT(1:1024, channel) .* kaiserWindowLong(1:1024)';
@@ -70,7 +70,7 @@ function frameF = filterbank(frameT, frameType, winType)
                 error('filterbank, l[20]: Unsupported window type input!')
             end
 
-            frameF = mdct4(frameT);
+            frameF(:, channel) = mdct4(frameT(:, channel));
         elseif strcmp(frameType, 'LPS')
             if strcmp(winType, 'KBD')
                 frameT(1:448, channel) = 0;
@@ -84,7 +84,7 @@ function frameF = filterbank(frameT, frameType, winType)
                 error('filterbank, l[20]: Unsupported window type input!')
             end
 
-            frameF = mdct4(frameT);
+            frameF(:, channel) = mdct4(frameT(:, channel));
         elseif strcmp(frameType, 'ESH')
             % Splits the frame into sub-frames
             [subFrames, ~] = buffer(frameT(449:end-448, channel), 256, 128, 'nodelay');
diff --git a/Level_1/iAACoder1.m b/Level_1/iAACoder1.m
index a1ee75d..448212a 100644
--- a/Level_1/iAACoder1.m
+++ b/Level_1/iAACoder1.m
@@ -1,5 +1,5 @@
 function x = iAACoder1(AACSeq1, fNameOut)
-%Implementation of WHAT?? //TODO!!
+%Implementation of AAC decoder
 %   Usage x = iAACoder1(AACSeq1, fNameOut), where:
 %       Inputs
 %       - fNameOut is the filename and path of the file that will be
@@ -13,8 +13,12 @@ function x = iAACoder1(AACSeq1, fNameOut)
 %       Output
 %       - x is an array containing the decoded audio samples
 
+    % Initializes an array to hold the decoded samples
     decodedAudio(1024 * (length(AACSeq1) + 1), 2) = 0;
+    % Initializes an array to hold both audio channels
     frameF(1024, 2) = 0;
+    
+    % Decodes audio file
     for i = 0:length(AACSeq1)-1
         currFrameStart = i * 1024 + 1;
         currFrameStop = currFrameStart + 2047;
diff --git a/Level_1/iFilterbank.m b/Level_1/iFilterbank.m
index ad812fd..c71e8d5 100644
--- a/Level_1/iFilterbank.m
+++ b/Level_1/iFilterbank.m
@@ -48,7 +48,7 @@ function frameT = iFilterbank(frameF, frameType, winType)
     % Applies appropriate window to the frame
     for channel=1:2
         if strcmp(frameType, 'OLS')
-            frameT = imdct4(frameF);
+            frameT(:, channel) = imdct4(frameF(:, channel));
 
             if strcmp(winType, 'KBD')
                 frameT(:, channel) = frameT(:, channel) .* kaiserWindowLong(:);
@@ -58,7 +58,7 @@ function frameT = iFilterbank(frameF, frameType, winType)
                 error('filterbank, l[20]: Unsupported window type input!')
             end
         elseif strcmp(frameType, 'LSS')
-            frameT = imdct4(frameF);
+            frameT(:, channel) = imdct4(frameF(:, channel));
 
             if strcmp(winType, 'KBD')
                 frameT(1:1024, channel) = frameT(1:1024, channel) .* kaiserWindowLong(1:1024)';
@@ -72,7 +72,7 @@ function frameT = iFilterbank(frameF, frameType, winType)
                 error('filterbank, l[20]: Unsupported window type input!')
             end
         elseif strcmp(frameType, 'LPS')
-            frameT = imdct4(frameF);
+            frameT(:, channel) = imdct4(frameF(:, channel));
 
             if strcmp(winType, 'KBD')
                 frameT(1:448, channel) = 0;
@@ -94,9 +94,9 @@ function frameT = iFilterbank(frameF, frameType, winType)
                 elseif strcmp(winType, 'SIN')
                     subFrame = subFrame .* sinWindowShort';
                 end
-
-                frameT(449 + (subFrameIndex - 1) * 128 + 1:449 + (subFrameIndex + 1) * 128) = ...
-                    frameT(449 + (subFrameIndex - 1) * 128 + 1:449 + (subFrameIndex + 1) * 128) + subFrame';
+                
+                frameT(448 + (subFrameIndex - 1) * 128 + 1:448 + (subFrameIndex + 1) * 128, channel) = ...
+                    frameT(448 + (subFrameIndex - 1) * 128 + 1:448 + (subFrameIndex + 1) * 128, channel) + subFrame;
             end
         end
     end