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41 lines
1.9 KiB
41 lines
1.9 KiB
function [SNR, bitrate, compression] = demoAAC3(fNameIn, fNameOut, frameAACoded)
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%Function that demonstrates usage of the level 3 code
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% Usage [SNR, bitrate, compression] = demoAAC3(fNameIn, fNameOut, frameAACoded), where:
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% Inputs
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% - fNameIn is the filename and path of the file to encode
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% - fNameOut is the filename and path of the wav file that will be
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% written after decoding
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% - frameAACoded is the filename and path of the mat file that will
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% be written after encoding
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%
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% Output
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% - SNR is the signal to noise ration computed after successively
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% encoding and decoding the audio signal
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% - bitrate is the bits per second
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% - compression is the ratio of the bitrate before the encoding to
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% the bitrate after it
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AACSeq3 = AACoder3(fNameIn, frameAACoded);
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totalSize = 0; % In bits
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for frameIndex = 1:length(AACSeq3)
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totalSize = totalSize + 2; % frameType
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totalSize = totalSize + 2 * 4 * 4; % TNS coefficients
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totalSize = totalSize + length(AACSeq3(frameIndex).chl.G) * 16;
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totalSize = totalSize + length(AACSeq3(frameIndex).chr.G) * 16;
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totalSize = totalSize + length(AACSeq3(frameIndex).chl.sfc);
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totalSize = totalSize + length(AACSeq3(frameIndex).chr.sfc);
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totalSize = totalSize + length(AACSeq3(frameIndex).chl.stream);
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totalSize = totalSize + length(AACSeq3(frameIndex).chr.stream);
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totalSize = totalSize + 4; % Codebook of left channel
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totalSize = totalSize + 4; % Codebook of right channel
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end
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decodedAudio = iAACoder3(AACSeq3, fNameOut);
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bitrate = totalSize / (length(decodedAudio) / 48000);
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[audioData, ~] = audioread(fNameIn);
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compression = (2 * length(audioData) * 16) / (length(audioData) / 48000) / bitrate;
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SNR = snr(audioData(1025:end-1378, :), audioData(1025:end-1378, :) - decodedAudio(1025:length(audioData)-1378, :));
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end
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