wavwr.m

This code was used for making the practical measurements in section 2.3 of my thesis. This Matlab co

function wavwri(waveData,sRate,res,nchannel,wavefile,user_limit)

%WAVWRI Saves Microsoft Windows .WAV format sound files.
%   WAVWRI(y,Fs,res,nchannel,wavefile,user_limit) saves a .WAV format file.
%
%   The input arguments for WAVWRITE are as follows:
%
%       y           The sampled data to save
%       Fs          The rate at which the data was sampled
%       res         Resulution, 8 or 16 (bits/sample)
%       nchannel    Number of channels, 1 or 2
%       wavefile    A string containing the name of the .WAV file to create
%       user_limit  OPTIONAL: if supplied, the data will be treated as if it had
%                   maximum magnitude of user_limit.  Otherwise the data will be
%                   scaled so that its actual maximum magnitude goes to full scale.
%                   So, if you want the actual values of your data to appear in the
%                   WAV file, despite the fact that the max. mag. of your data may
%                   not be full scale, for 16-bit you would supply a user_limit of
%                   32767.

if (nargin~=5 & nargin~=6)
   error(['WAVWRI needs 5 or 6 arguments, got ' int2str(nargin)]);
end

limit=max(max(abs(waveData)));

if nargin==6
   if limit <= user_limit
      limit = user_limit;
   else
      error(['a limit of ' num2str(user_limit) ' was passed in but actual limit is ' num2str(limit)]);
   end;
end;

waveData=waveData/limit*(2^(res-1) - 1);

if res==8 waveData=waveData+128; end;

fid=fopen(wavefile,'wb','l');

if fid ~= -1
        [m,n]=size(waveData);
        nsamples=m*n;
        fac=res/8;

        riffsize=36+nsamples*fac;

        % write riff chunk
        fwrite(fid,'RIFF','uchar');
        fwrite(fid,riffsize,'ulong');
        fwrite(fid,'WAVE','uchar');

        % write format sub-chunk
        fwrite(fid,'fmt ','uchar');
        fwrite(fid,16,'ulong');

        fwrite(fid,1,'ushort');         % PCM format
        fwrite(fid,nchannel,'ushort');  % 1 or 2 channel
        fwrite(fid,sRate,'ulong');      % samples per second
        fwrite(fid,fac*sRate*nchannel,'ulong');  % average bytes per second
        fwrite(fid,fac*nchannel,'ushort');       % block alignment
        fwrite(fid,fac*8,'ushort');     % bits per sample

        % write data sub-chunck
        fwrite(fid,'data','uchar');
        fwrite(fid,nsamples*fac,'ulong');
        
        if nchannel==2 waveData=waveData(:);  end;   % Wenn Stereo
        
        if fac==2
           fwrite(fid,waveData,'ushort');   % 16 bit
        else
           fwrite(fid,waveData,'uchar');    %  8 bit
        end;

        fclose(fid);
else
	error(['Can''t open .WAV file ' wavefile ' for output!']);
end;