wavread, wavwrite and sound

%SOUND Play a vector as a sound.
%  sound (s, Fs, NBits)
%  Plays the audio data stored in the vector s, at the sampling
%  frequency Fs and the number of bits per sample NBits to the speakers. 
%
%  Author: NM <Nilesh Madhu>
%  Created: 15 September 2003
%  Copyright (C) 2003 Nilesh Madhu
%
%  This file is part of Octave distribution at the Institute for 
%  Communications Acoustics (IKA) at the RU Bochum.
%

function sound(s, Fs, NBits)

% Handling the different sampling frequencies in linux is difficult using the 
% octave PLAYAUDIO command. As a result, a work around solution is to copy the 
% data into a '.wav' file temporarily and then play this wave file by issung a 
% SYSTEM call to PLAY. If no sampling frequency is mentioned, the default sampling
% frequency is 8kHz at 16 bits (2 bytes) per sample per channel.

SamplingFrequency = 8000;		% Sampling frequency.
BitspSamp = 16;				% number of bits per sample.
if nargin == 2
	SamplingFrequency = Fs;
	if nargin == 3
		BitspSamp = NBits;
	end
end
wavwrite("temp.wav", s, SamplingFrequency , BitspSamp);

commandstr = ['play -r ', int2str(SamplingFrequency),' temp.wav'];
system(commandstr);
cleanupstr = ('rm -f temp.wav');
system(cleanupstr);

%WAVREAD Simulates the matlab wavread command.
%  [S Fs NBits] = wavread(WAVEFILENAME)
 
%Information about WAVREAD
%  Wave files are in the Resource Interchange File Format (RIFF), 
%  which consists of a variable number of chunks containing either 
%  header information (for example, the wave format of sound samples) or 
%  data (the samples themselves). (See www.sonicspot.com/ for more information.)  

function [s, Fs, NBits] = wavread(WAVEFILENAME)

LName = length(WAVEFILENAME);

if (LName < 3)
	WAVEFILENAME = [WAVEFILENAME,'.wav'];
else
	file_ext = WAVEFILENAME(length(WAVEFILENAME)-2:end);
	if (file_ext~='wav')
		WAVEFILENAME = [WAVEFILENAME,'.wav'];
	end
end

fid = fopen(WAVEFILENAME, 'r', 'ieee-le');

if fid < 0
	disp('Error! Wave file does not exist or path is mis-spelled');
	return;
end

% Start reading in the RIFF data.

ChunkID = char(fread(fid,4,"uchar",0,"ieee-le").');
if (ChunkID~='RIFF')
	disp('Error! File is not in a RIFF format');
	return;
end

% Get the file size
fseek(fid, 0x04, SEEK_SET);	% Rewinding the file.
ChunkSize = fread(fid, 1, "uint", 0, "ieee-le");

% Check the RIFF Type ID. Should be 'WAVE'
RIFFTypeID = char(fread(fid, 4, "uchar", 0, "ieee-le").');
if (RIFFTypeID ~= 'WAVE')
	disp('Error! File is not a WAVE file');
	return;
end

ChunkID = fread(fid, 4, "uchar", 0, "ieee-le");			% Returns the string 'fmt'
ChunkSiz = fread(fid, 1, "uint", 0, "ieee-le");			% always 16 bytes
Compression = fread(fid, 1, "int16", 0, "ieee-le");		% Compression code
NumberofChannels = fread(fid, 1, "int16", 0, "ieee-le");	% Number of channels
Fs = fread(fid, 1, "int32", 0, "ieee-le");			% Sampling rate
Byps = fread(fid, 1, "int32", 0, "ieee-le");			% Bytes per second
BlockAlign = fread(fid, 1, "int16", 0, "ieee-le");		% Block Align
NBits = fread(fid, 1, "int16", 0, "ieee-le");			% NBits
ChunkData = char(fread(fid, 4, "uchar", 0, "ieee-le").');	% 'data'
NumberofDataBytes = (fread(fid, 1, "uint", 0, "ieee-le"));	
NumberofSamples = NumberofDataBytes/(NumberofChannels*(NBits/8)); % number of samples

% Enough data obtained for reading in the data based upon the number of
% significant bits per sample.
switch NBits
	case 8
		MultFact = 128;
		dataPrecision = 'uchar';
	case 16
		MultFact = 32768;
		dataPrecision = 'int16';
	case 24
		MultFact = 2^23;
		dataPrecision = 'int16';
end

s = fread(fid, [NumberofSamples NumberofChannels], dataPrecision, 0, 'ieee-le');

if NBits == 8
	s = (s/MultFact) - 1;
else
	s = s/MultFact;
end

fclose(fid);

%WAVWRITE Write a vector into a wave file.
%  wavwrite (FileName, s, Fs, NBits)
%  Writes the audio data stored in the vector s, at the sampling
%  frequency Fs and the number of bits per sample NBits to the file FileName. 
%
%  Author: NM <Nilesh Madhu>
%  Created: 15 September 2003
%  Copyright (C) 2003 Nilesh Madhu
%
%  This file is part of Octave distribution at the Institute for 
%  Communications Acoustics (IKA) at the RU Bochum.
%

function wavwrite(FileName, s, Fs, NBits)

% Handling the different sampling frequencies in linux is difficult using the 
% octave PLAYAUDIO command. As a result, a work around solution is to copy the 
% data into a '.wav' file temporarily and then play this wave file by issung a 
% SYSTEM call to PLAY. If no sampling frequency is mentioned, the default sampling
% frequency is 8kHz at 16 bits (2 bytes) per sample per channel.

SamplingFrequency = 8000;		% Sampling frequency.

if nargin > 2
	SamplingFrequency = Fs;
	if nargin < 4
		NBits = 16;		% number of significant bits per sample.
	end
end

% Setting the parameters for writing data depending upon the
% number of significant bits.
switch NBits
	case 8
		MultFact = 128;
		dataPrecision = 'uchar';
		s = (s+1)*MultFact;
	case 16
		MultFact = 32768;
		dataPrecision = 'int16';
		s = s*MultFact;
	case 24
		MultFact = 2^23;
		dataPrecision = 'int16';
		s = s*MultFact;
end

addExt = 0;

if length(FileName) < 3
	addExt = 1;
else
	file_ext = FileName(end-2:end);
	if file_ext~='wav' 
		addExt = 1;
	end
end

if addExt
	FileName = [FileName,'.wav'];
end
		
[fid msg] = fopen(FileName,"wb", "ieee-le");

if fid < 0
	disp(msg);
	return;
end

[NumSamples NumChannels] = size(s);
if NumSamples < NumChannels
	s = s.';
	[NumSamples NumChannels] = size(s);
end
 
% Writing into the '.wav' file. 

chunkDataSize = NumSamples*NumChannels*NBits/8;	 % Size of the samples in the wav file.

% The RIFF Chunk
RIFFChunkID = toascii("RIFF");	% 'RIFF'
countRIFFCkID = fwrite(fid, RIFFChunkID, 'uchar');
RIFFChunkSize = 36+chunkDataSize;

countRIFFCkSiz = fwrite(fid, RIFFChunkSize, 'uint');

% The WAVE type ID and the FORMAT Chunk.
RIFFTypeID = toascii("WAVE");	% 'WAVE'
countRIFFTypeID = fwrite(fid, RIFFTypeID, 'uchar'); 
ChunkFmt = toascii("fmt ");	% 'fmt '
countRIFFTypeID = fwrite(fid, ChunkFmt, 'uchar'); 
RIFFTypeSiz = 16;                       % always 16 bytes
countRIFFTypeSiz = fwrite(fid, RIFFTypeSiz, 'uint');		


% Specific data for the file
CompressionFormat = 1;			% Uncompressed/ PCM
NumberofChannels =  NumChannels;
BlockAlign = (NBits/8)*NumChannels;
AvgBytespSec = SamplingFrequency*BlockAlign;


countCompression = fwrite(fid, CompressionFormat, 'int16');
countNumChannels = fwrite(fid, NumChannels, 'int16');
countFs = fwrite(fid, SamplingFrequency, 'int32');
countAvgByps = fwrite(fid, AvgBytespSec, 'int32');
countBlockAlign = fwrite(fid, BlockAlign, 'int16');
countNBits = fwrite(fid, NBits, 'int16');

% Chunk DATA
chunkData = toascii("data");	% 'data'
countChunkData = fwrite(fid, chunkData);
countchunkDataSize = fwrite(fid, chunkDataSize, 'uint');

countAudioSamples = fwrite(fid, s, dataPrecision, 0, 'ieee-le');
%for i = 1:NumSamples
%	for j = NumChannels
%		fwrite(fid, s(i,j)*32768, 'int16');
%	end
%end
fclose(fid);
%command = ['play -r ',num2str(SamplingFrequency),' temp.wav'];
%system(command);