gusucode.com > 《MATLAB图像与视频处理实用案例详解》代码 > 《MATLAB图像与视频处理实用案例详解》代码/第 19 章 基于语音识别的信号灯图像模拟控制技术/voicebox/writewav.m
function fidx=writewav(d,fs,filename,mode,nskip,mask)
%WRITEWAV Creates .WAV format sound files FIDX=(D,FS,FILENAME,MODE,NSKIP,MASK)
%
% The input arguments for WRITEWAV are as follows:
%
% D The sampled data to save
% FS The rate at which the data was sampled
% FILENAME A string containing the name of the .WAV file to create or
% alternatively the FIDX output from a previous writewav call
% MODE String containing any reasonable mixture of flags below (*=default):
% NSKIP Number of samples to skip before writing or -1[default] to continue from previous write
% Only valid if FIDX is specified for FILENAME
% MASK specifies the speaker positions included as a bit mask (see readwav)
%
% MODE flags (*=default):
% Precision: 'a' for 8-bit A-law PCM
% 'u' for 8-bit mu-law PCM
% '16' * for 16 bit PCM data
% '8' for 8 bit PCM data
% ... any number in the range 2 to 32 for PCM
% 'v' 32-bit floating point
% 'V' 64-bit floating point
% 'c' embed in 16 bits
% 'C' embed in 24 bits
% 'L' embed in 32 bits
% Dither: 'w' White triangular dither of amplitude +-1 LSB (PCM modes only)
% 'h' High pass dither (filtered by 1-1/z) (PCM modes only)
% 'l' Low pass dither (filtered by 1+1/z) (PCM modes only)
% Scaling: 's' * Auto scale to make data peak = +-1
% 'r' Raw unscaled data (integer values)
% 'q' Scaled to make unity mean square correspond to 0dBm according to G.711
% 'p' Scaled to make +-1 equal full scale
% 'o' Scale to bin centre rather than bin edge (e.g. 127 rather than 127.5 for 8 bit values)
% (can be combined with n+p,r,s modes)
% 'n' Scale to negative peak rather than positive peak (e.g. 128.5 rather than 127.5 for 8 bit values)
% (can be combined with o+p,r,s modes)
% 'g' Include a gain factor so that "readwav" will restore the correct level
% Offset: 'y' * Correct for offset in <=8 bit PCM data
% 'z' Do not apply offset correction
% Format: 'x' use WAVEFORMATEX format (default for non PCM)
% 'X' use WAVEFORMATEXTENSIBLE (default if MASK input is given)
% 'e' use original WAVEFORMAT (default for PCM)
% 'E' include a 'fact' chunk (default for non-PCM)
% File I/O: 'f' Do not close file on exit
% 'd' Look in data directory: voicebox('dir_data')
%
%
% Output Parameter:
%
% FIDX Information row vector containing the element listed below.
%
% (1) file id
% (2) current position in file (in samples, 0=start of file)
% (3) dataoff length of file header in bytes
% (4) nsamp number of samples
% (5) nchan number of channels
% (6) nbyte bytes per data value
% (7) bits number of bits of precision
% (8) code Data format: 1=PCM, 2=ADPCM, 6=A-law, 7=Mu-law
% (9) fs sample frequency
% (10) dither state variable
% (11) gain in dB (in INST chunk)
%
% Note: WRITEWAV will create an 16-bit PCM, auto-scaled wave file by default.
% For stereo data, d(:,1) is the left channel and d(:,2) the right
%
% See also READWAV
% *** Note on scaling ***
% If we want to scale signal values in the range +-1 to an integer in the
% range [-128,127] then we have four plausible choices corresponding to
% scale factors of (a) 127, (b) 127.5, (c) 128 or (d) 128.5 but each choice
% has disadvantages.
% For forward scaling: (c) and (d) cause clipping on inputs of +1.
% For reverse scaling: (a) and (b) can generate output values < -1.
% Any of these scalings can be selected via the mode input: (a) 'o', (b) default, (c) 'on', (d) 'n'
% Copyright (C) Mike Brookes 1998-2011
% Version: $Id: writewav.m,v 1.5 2011/05/02 16:51:34 dmb Exp $
%
% VOICEBOX is a MATLAB toolbox for speech processing.
% Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You can obtain a copy of the GNU General Public License from
% http://www.gnu.org/copyleft/gpl.html or by writing to
% Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Acknowledgements
% Thanks to Hugh Barnes for sorting out seek problems with MATLAB 6.5
% Bugs/suggestions
% Save the following factors in FIDX: (a) scale factor, (b) offset (c) low/high clip limits
% (d) dither position (e) rounding position
if nargin<3
error('Usage: WRITEWAV(data,fs,filename,mode,nskip)');
end
if nargin<6
mask=0;
end
info=zeros(1,11);
info(9)=fs;
if nargin<4
mode='s';
else
mode = [mode(:).' 's']; % ensure that there is always a scaling option specified
end
info(8)=1; % default mode is PCM
mno=all(mode~='o'); % scale to input limits not output limits
k=find((mode>='0') & (mode<='9'),1);
if k,
info(7)=sscanf(mode(k:end),'%d'); % valid bits per data value
else
info(7)=16;
end
if any(mode=='c')
info(6)=2; % bytes per data value = 2
elseif any(mode=='C')
info(6)=3; % bytes per data value = 3
elseif any(mode=='L')
info(6)=4; % bytes per data value = 4
else
info(6)=ceil(info(7)/8); % bytes per data value
end
lo=-pow2(0.5,info(7));
hi=-1-lo;
pk=pow2(0.5,8*info(6))*(1-(mno/2-all(mode~='n'))/lo); % use modes o and n to determine effective peak
% should perhaps have another variable besides info(7) to control dither position (or set info(7) later)
% for A and mu law the dither position is not the same as the number of bits.
if any(mode=='a')
info(8)=6;
pk=4032+mno*64;
info(7)=8; % Some sources say this should be listed as 16 valid bits
info(6)=1;
elseif any(mode=='u')
info(8)=7;
pk=8031+mno*128;
info(7)=8; % Some sources say this should be listed as 16 valid bits
info(6)=1;
elseif any(mode=='v')
pk=1;
mode(end)='r'; % default scaling is 'r'
info(6)=4; % bytes
info(7)=32; % bits
info(8)=3; % WAVE type
elseif any(mode=='V')
pk=1;
mode(end)='r'; % default scaling is 'r'
info(6)=8; % bytes
info(7)=64; % bits
info(8)=3; % WAVE type
end % is this pk value correct ?
sc=mode(find((mode>='p') & (mode<='s'),1)); % find the first scaling option (always exists)
z=128*all(mode~='z');
if any(mode=='w')
di='w'; % select dither mode
elseif any(mode=='h')
di='h';
elseif any(mode=='l')
di='l';
else
di='n';
end
% Now sort out which wave format to use
if any(mode=='e')
wavtype=1;
elseif any(mode=='x')
wavtype=2;
elseif any(mode=='X') || nargin>=6
wavtype=3;
else
wavtype=2-(info(8)==1);
end
wavfmt=info(8)*(wavtype<3)+(pow2(16)-2)*(wavtype==3);
fmtlen=[16 18 40]; % length of format chunk
factlen=12*(any(mode=='E') || info(8)~=1);
instlen=16*any(mode=='g'); % length of INST chunk (force to be even since some readers do not like odd lengths)
wavlen=[36 38 60]+factlen+instlen; % length of entire WAVE chunk except for the data (not including 8 byte RIFF header)
[n,nc]=size(d);
if n==1
n=nc;
nc=1;
else
d = d.';
end;
if nc>32
error('WRITEWAV: attempt to write a sound file with >32 channels');
end
nc=max(nc,1);
ncy=nc*info(6); % bytes per sample time
nyd=n*ncy; % bytes to write
if ischar(filename)
if any(mode=='d')
filename=fullfile(voicebox('dir_data'),filename);
end
ny=nyd;
if isempty(findstr(filename,'.'))
filename=[filename,'.wav'];
end
fid=fopen(filename,'wb+','l');
if fid == -1
error('Can''t open %s for output',filename);
end
info(1)=fid;
fwrite(fid,'RIFF','uchar'); % main RIFF header
fwrite(fid,wavlen(wavtype)+2*ceil(ny/2),'ulong'); %
fwrite(fid,'WAVEfmt ','uchar'); % write "WAVE" ID and "fmt" chunk
fwrite(fid,[fmtlen(wavtype) 0 wavfmt nc],'ushort'); % chunk size, format code, number of channels
fwrite(fid,[fs fs*ncy],'ulong'); % sample rate, bytes per sec
switch wavtype
case 1
fwrite(fid,[ncy info(7)],'ushort'); % block size, bits-per-sample
case 2
fwrite(fid,[ncy info(7)],'ushort'); % block size, bits-per-sample
fwrite(fid,0,'ushort'); % size of the extension=0
case 3
fwrite(fid,[ncy 8*info(6)],'ushort'); % block size, bits-per-sample (aways a multiple of 8)
fwrite(fid,[22 info(7)],'ushort'); % size of the extension=22, valid bits
fwrite(fid,[mask info(8)],'ulong'); % speaker position mask, encoding format
fwrite(fid,[0 16 128 43520 14336 29083],'ushort'); % GUID
end
if factlen
fwrite(fid,'fact','uchar'); % fact chunk header
fwrite(fid,[4 n],'ulong'); % length in bytes + number of samples
end
if instlen
fwrite(fid,'inst','uchar'); % fact chunk header
fwrite(fid,instlen-8,'ulong'); % length in bytes
fwrite(fid,zeros(1,instlen-8),'uchar'); % inst data (zero for now)
end
fwrite(fid,'data','uchar'); % data header
fwrite(fid,ny,'ulong'); % data length in bytes
nskip=0; % over-ride any nskip argument
info(3)=8+wavlen(wavtype); % length of all header information
info(4)=n; % number of samples (per channel)
info(2)=n; % current file position (in samples)
info(10)=rand(1); % seed for dither generation
else
info=filename;
fid=info(1);
fseek(fid,0,1); % go to end of file
if nargin<5 || nskip<0
nskip=info(2); % use previous high water mark
end
info(2)=n+nskip; % file position following this write operation (in samples)
ny=nyd+nskip*ncy; % file position following this write operation (in bytes following header)
if n && (info(2)>info(4)) % update high water mark
if ~info(4) % if no data written previously
fseek(fid,22,-1); fwrite(fid,nc,'ushort'); % update number of channels
fseek(fid,28,-1); fwrite(fid,fs*ncy,'ulong'); % update bytes/second
fwrite(fid,ncy,'ushort'); % update bytes/sample
end
fseek(fid,4,-1); fwrite(fid,wavlen(wavtype)+2*ceil(ny/2),'ulong'); % update RIFF length
if factlen
fseek(fid,wavlen(wavtype)-4-instlen,-1); fwrite(fid,n,'ulong'); % update FACT number of samples
end
fseek(fid,4+wavlen(wavtype),-1); fwrite(fid,ny,'ulong'); % update DATA length
info(4)=info(2);
end
end
info(5)=nc;
if n
if sc~='r' % 'r' = no scaling
if sc=='s' % 's' = scale to peak signal
pd=max(abs(d(:)));
pd=pd+(pd==0); % scale to 1 if data is all zero
elseif sc=='p' % 'p' = scale to +-1 = full scale
pd=1;
else % 'q' = scale to 0dBm
if info(8)==7 % mu-law
pd=2.03761563;
else % A-law or anything else
pd=2.03033976;
end
end
if instlen
info(11)=min(max(ceil(20*log10(pd)),-128),127);
d=pk*10^(-0.05*info(11))*d;
if fseek(fid,0,-1) % MATLAB V6.5 fails if this is omitted
error('Cannot rewind file');
end
if fseek(fid,info(3)-instlen+2,-1);
error('Cannot seek to INST chunk gain byte');
end
fwrite(fid,info(11),'schar'); % write the INST gain in dB
else
d=pk/pd*d;
end
end
if fseek(fid,0,-1) % MATLAB V6.5 fails if this is omitted
error('Cannot rewind file');
end
if fseek(fid,info(3)+nskip*nc*info(6),-1)
error('Cannot seek to byte %d in output file',info(3)+nskip*nc*info(6));
end
if info(8)==3 % floating point
if info(6)==4
fwrite(fid,d,'float32');
else
fwrite(fid,d,'float64');
end
else % integer data
if info(8)<6 % PCM
if di=='n'
d=round(d);
else
[d,info(10)]=ditherq(d,di,info(10));
end
d=min(max(d,lo),hi)*pow2(1,8*info(6)-info(7)); % clip data and shift to most significant bits
else % mu or A law
z=0;
if info(8) < 7
d=lin2pcma(d,213,1);
else
d=lin2pcmu(d,1);
end
end
if info(6)<3
if info(6)<2
fwrite(fid,d+z,'uchar');
else
fwrite(fid,d,'short');
end
else
if info(6)<4
d=d(:)';
d2=floor(d/65536);
d=d-65536*d2;
fwrite(fid,[rem(d,256); floor(d/256); d2+256*(d2<0)],'uchar');
else
fwrite(fid,d,'long');
end
end
if rem(ny,2) % pad to an even number of bytes
fwrite(fid,0,'uchar');
end
end
end
if all(mode~='f')
fclose(fid);
end
if nargout
fidx=info;
end