function AACSeq2 = AACoder2(fNameIn) %Implementation of AAC encoder % Usage AACSeq2 = AACoder2(fNameIn), where: % Inputs % - fNameIn is the filename and path of the file to encode % % Output % - AACSeq2 is an array of structs containing K structs, where K is % the number of computed frames. Every struct of the array consists % of a frameType, a winType, chl.TNScoeffs which are the quantized TNS % coefficients of this frame's left channel, chr.TNScoeffs which are % the quantized TNS coefficients of this frame's right channel, % chl.frameF which are the MDCT coefficients of this frame's left % channel, chr.frameF which are the MDCT coefficients of this frame's % right channel % Declares constant window type WINDOW_TYPE = 'KBD'; % Reads the audio file [originalAudioData, ~] = audioread(fNameIn); % Splits the audio in frames and determines the type of each frame frameTypes{fix((length(originalAudioData) - 1025) / 1024)} = 'OLS'; frameTypes{1} = 'OLS'; for i = 1:length(frameTypes) - 2 nextFrameStart = (i + 1) * 1024 + 1; nextFrameStop = nextFrameStart + 2047; frameTypes{i+1} = SSC(1, originalAudioData(nextFrameStart:nextFrameStop, :), frameTypes{i}); end % Assigns a type to the last frame if strcmp(frameTypes{length(frameTypes) - 1}, 'LSS') frameTypes{length(frameTypes)} = 'ESH'; elseif strcmp(frameTypes{length(frameTypes) - 1}, 'ESH') frameTypes{length(frameTypes)} = 'ESH'; else frameTypes{length(frameTypes)} = 'OLS'; end % Encodes audio file AACSeq2(length(frameTypes)) = struct; for i = 0:length(frameTypes) - 1 currFrameStart = i * 1024 + 1; currFrameStop = currFrameStart + 2047; frameF = filterbank(originalAudioData(currFrameStart:currFrameStop, :), frameTypes{i+1}, WINDOW_TYPE); [frameF(:, 1), TNScoeffsL] = TNS(frameF(:, 1), frameTypes{i+1}); [frameF(:, 2), TNScoeffsR] = TNS(frameF(:, 2), frameTypes{i+1}); AACSeq2(i + 1).frameType = frameTypes(i + 1); AACSeq2(i + 1).winType = WINDOW_TYPE; AACSeq2(i + 1).chl.TNScoeffs = TNScoeffsL; AACSeq2(i + 1).chr.TNScoeffs = TNScoeffsR; AACSeq2(i + 1).chl.frameF = frameF(:, 1); AACSeq2(i + 1).chr.frameF = frameF(:, 2); end if false [idx,label] = grp2idx(sort(frameTypes)); hist(idx,unique(idx)); set(gca,'xTickLabel',label) sum(idx(:) == 1) sum(idx(:) == 2) sum(idx(:) == 3) sum(idx(:) == 4) end end