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 READWAV0001 function fidx=writewav(d,fs,filename,mode,nskip,mask) 0002 %WRITEWAV Creates .WAV format sound files FIDX=(D,FS,FILENAME,MODE,NSKIP,MASK) 0003 % 0004 % The input arguments for WRITEWAV are as follows: 0005 % 0006 % D The sampled data to save 0007 % FS The rate at which the data was sampled 0008 % FILENAME A string containing the name of the .WAV file to create or 0009 % alternatively the FIDX output from a previous writewav call 0010 % MODE String containing any reasonable mixture of flags below (*=default): 0011 % NSKIP Number of samples to skip before writing or -1[default] to continue from previous write 0012 % Only valid if FIDX is specified for FILENAME 0013 % MASK specifies the speaker positions included as a bit mask (see readwav) 0014 % 0015 % MODE flags (*=default): 0016 % Precision: 'a' for 8-bit A-law PCM 0017 % 'u' for 8-bit mu-law PCM 0018 % '16' * for 16 bit PCM data 0019 % '8' for 8 bit PCM data 0020 % ... any number in the range 2 to 32 for PCM 0021 % 'v' 32-bit floating point 0022 % 'V' 64-bit floating point 0023 % 'c' embed in 16 bits 0024 % 'C' embed in 24 bits 0025 % 'L' embed in 32 bits 0026 % Dither: 'w' White triangular dither of amplitude +-1 LSB (PCM modes only) 0027 % 'h' High pass dither (filtered by 1-1/z) (PCM modes only) 0028 % 'l' Low pass dither (filtered by 1+1/z) (PCM modes only) 0029 % Scaling: 's' * Auto scale to make data peak = +-1 0030 % 'r' Raw unscaled data (integer values) 0031 % 'q' Scaled to make unity mean square correspond to 0dBm according to G.711 0032 % 'p' Scaled to make +-1 equal full scale 0033 % 'o' Scale to bin centre rather than bin edge (e.g. 127 rather than 127.5 for 8 bit values) 0034 % (can be combined with n+p,r,s modes) 0035 % 'n' Scale to negative peak rather than positive peak (e.g. 128.5 rather than 127.5 for 8 bit values) 0036 % (can be combined with o+p,r,s modes) 0037 % 'g' Include a gain factor so that "readwav" will restore the correct level 0038 % Offset: 'y' * Correct for offset in <=8 bit PCM data 0039 % 'z' Do not apply offset correction 0040 % Format: 'x' use WAVEFORMATEX format (default for non PCM) 0041 % 'X' use WAVEFORMATEXTENSIBLE (default if MASK input is given) 0042 % 'e' use original WAVEFORMAT (default for PCM) 0043 % 'E' include a 'fact' chunk (default for non-PCM) 0044 % File I/O: 'f' Do not close file on exit 0045 % 'd' Look in data directory: voicebox('dir_data') 0046 % 0047 % 0048 % Output Parameter: 0049 % 0050 % FIDX Information row vector containing the element listed below. 0051 % 0052 % (1) file id 0053 % (2) current position in file (in samples, 0=start of file) 0054 % (3) dataoff length of file header in bytes 0055 % (4) nsamp number of samples 0056 % (5) nchan number of channels 0057 % (6) nbyte bytes per data value 0058 % (7) bits number of bits of precision 0059 % (8) code Data format: 1=PCM, 2=ADPCM, 6=A-law, 7=Mu-law 0060 % (9) fs sample frequency 0061 % (10) dither state variable 0062 % (11) gain in dB (in INST chunk) 0063 % 0064 % Note: WRITEWAV will create an 16-bit PCM, auto-scaled wave file by default. 0065 % For stereo data, d(:,1) is the left channel and d(:,2) the right 0066 % 0067 % See also READWAV 0068 0069 % *** Note on scaling *** 0070 % If we want to scale signal values in the range +-1 to an integer in the 0071 % range [-128,127] then we have four plausible choices corresponding to 0072 % scale factors of (a) 127, (b) 127.5, (c) 128 or (d) 128.5 but each choice 0073 % has disadvantages. 0074 % For forward scaling: (c) and (d) cause clipping on inputs of +1. 0075 % For reverse scaling: (a) and (b) can generate output values < -1. 0076 % Any of these scalings can be selected via the mode input: (a) 'o', (b) default, (c) 'on', (d) 'n' 0077 0078 % Copyright (C) Mike Brookes 1998-2011 0079 % Version: $Id: writewav.m 713 2011-10-16 14:45:43Z dmb $ 0080 % 0081 % VOICEBOX is a MATLAB toolbox for speech processing. 0082 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0083 % 0084 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0085 % This program is free software; you can redistribute it and/or modify 0086 % it under the terms of the GNU General Public License as published by 0087 % the Free Software Foundation; either version 2 of the License, or 0088 % (at your option) any later version. 0089 % 0090 % This program is distributed in the hope that it will be useful, 0091 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0092 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0093 % GNU General Public License for more details. 0094 % 0095 % You can obtain a copy of the GNU General Public License from 0096 % http://www.gnu.org/copyleft/gpl.html or by writing to 0097 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0098 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0099 0100 % Acknowledgements 0101 % Thanks to Hugh Barnes for sorting out seek problems with MATLAB 6.5 0102 0103 % Bugs/suggestions 0104 % Save the following factors in FIDX: (a) scale factor, (b) offset (c) low/high clip limits 0105 % (d) dither position (e) rounding position 0106 0107 0108 if nargin<3 0109 error('Usage: WRITEWAV(data,fs,filename,mode,nskip)'); 0110 end 0111 if nargin<6 0112 mask=0; 0113 end 0114 info=zeros(1,11); 0115 info(9)=fs; 0116 if nargin<4 0117 mode='s'; 0118 else 0119 mode = [mode(:).' 's']; % ensure that there is always a scaling option specified 0120 end 0121 info(8)=1; % default mode is PCM 0122 mno=all(mode~='o'); % scale to input limits not output limits 0123 k=find((mode>='0') & (mode<='9'),1); 0124 if k, 0125 info(7)=sscanf(mode(k:end),'%d'); % valid bits per data value 0126 else 0127 info(7)=16; 0128 end 0129 if any(mode=='c') 0130 info(6)=2; % bytes per data value = 2 0131 elseif any(mode=='C') 0132 info(6)=3; % bytes per data value = 3 0133 elseif any(mode=='L') 0134 info(6)=4; % bytes per data value = 4 0135 else 0136 info(6)=ceil(info(7)/8); % bytes per data value 0137 end 0138 lo=-pow2(0.5,info(7)); 0139 hi=-1-lo; 0140 pk=pow2(0.5,8*info(6))*(1-(mno/2-all(mode~='n'))/lo); % use modes o and n to determine effective peak 0141 % should perhaps have another variable besides info(7) to control dither position (or set info(7) later) 0142 % for A and mu law the dither position is not the same as the number of bits. 0143 if any(mode=='a') 0144 info(8)=6; 0145 pk=4032+mno*64; 0146 info(7)=8; % Some sources say this should be listed as 16 valid bits 0147 info(6)=1; 0148 elseif any(mode=='u') 0149 info(8)=7; 0150 pk=8031+mno*128; 0151 info(7)=8; % Some sources say this should be listed as 16 valid bits 0152 info(6)=1; 0153 elseif any(mode=='v') 0154 pk=1; 0155 mode(end)='r'; % default scaling is 'r' 0156 info(6)=4; % bytes 0157 info(7)=32; % bits 0158 info(8)=3; % WAVE type 0159 elseif any(mode=='V') 0160 pk=1; 0161 mode(end)='r'; % default scaling is 'r' 0162 info(6)=8; % bytes 0163 info(7)=64; % bits 0164 info(8)=3; % WAVE type 0165 end % is this pk value correct ? 0166 sc=mode(find((mode>='p') & (mode<='s'),1)); % find the first scaling option (always exists) 0167 z=128*all(mode~='z'); 0168 if any(mode=='w') 0169 di='w'; % select dither mode 0170 elseif any(mode=='h') 0171 di='h'; 0172 elseif any(mode=='l') 0173 di='l'; 0174 else 0175 di='n'; 0176 end 0177 0178 % Now sort out which wave format to use 0179 if any(mode=='e') 0180 wavtype=1; 0181 elseif any(mode=='x') 0182 wavtype=2; 0183 elseif any(mode=='X') || nargin>=6 0184 wavtype=3; 0185 else 0186 wavtype=2-(info(8)==1); 0187 end 0188 wavfmt=info(8)*(wavtype<3)+(pow2(16)-2)*(wavtype==3); 0189 fmtlen=[16 18 40]; % length of format chunk 0190 factlen=12*(any(mode=='E') || info(8)~=1); 0191 instlen=16*any(mode=='g'); % length of INST chunk (force to be even since some readers do not like odd lengths) 0192 wavlen=[36 38 60]+factlen+instlen; % length of entire WAVE chunk except for the data (not including 8 byte RIFF header) 0193 0194 0195 [n,nc]=size(d); 0196 if n==1 0197 n=nc; 0198 nc=1; 0199 else 0200 d = d.'; 0201 end; 0202 if nc>32 0203 error('WRITEWAV: attempt to write a sound file with >32 channels'); 0204 end 0205 nc=max(nc,1); 0206 ncy=nc*info(6); % bytes per sample time 0207 nyd=n*ncy; % bytes to write 0208 0209 if ischar(filename) 0210 if any(mode=='d') 0211 filename=fullfile(voicebox('dir_data'),filename); 0212 end 0213 ny=nyd; 0214 if isempty(findstr(filename,'.')) 0215 filename=[filename,'.wav']; 0216 end 0217 fid=fopen(filename,'wb+','l'); 0218 if fid == -1 0219 error('Can''t open %s for output',filename); 0220 end 0221 info(1)=fid; 0222 fwrite(fid,'RIFF','uchar'); % main RIFF header 0223 fwrite(fid,wavlen(wavtype)+2*ceil(ny/2),'ulong'); % 0224 fwrite(fid,'WAVEfmt ','uchar'); % write "WAVE" ID and "fmt" chunk 0225 fwrite(fid,[fmtlen(wavtype) 0 wavfmt nc],'ushort'); % chunk size, format code, number of channels 0226 fwrite(fid,[fs fs*ncy],'ulong'); % sample rate, bytes per sec 0227 switch wavtype 0228 case 1 0229 fwrite(fid,[ncy info(7)],'ushort'); % block size, bits-per-sample 0230 case 2 0231 fwrite(fid,[ncy info(7)],'ushort'); % block size, bits-per-sample 0232 fwrite(fid,0,'ushort'); % size of the extension=0 0233 case 3 0234 fwrite(fid,[ncy 8*info(6)],'ushort'); % block size, bits-per-sample (aways a multiple of 8) 0235 fwrite(fid,[22 info(7)],'ushort'); % size of the extension=22, valid bits 0236 fwrite(fid,[mask info(8)],'ulong'); % speaker position mask, encoding format 0237 fwrite(fid,[0 16 128 43520 14336 29083],'ushort'); % GUID 0238 end 0239 if factlen 0240 fwrite(fid,'fact','uchar'); % fact chunk header 0241 fwrite(fid,[4 n],'ulong'); % length in bytes + number of samples 0242 end 0243 if instlen 0244 fwrite(fid,'inst','uchar'); % fact chunk header 0245 fwrite(fid,instlen-8,'ulong'); % length in bytes 0246 fwrite(fid,zeros(1,instlen-8),'uchar'); % inst data (zero for now) 0247 end 0248 fwrite(fid,'data','uchar'); % data header 0249 fwrite(fid,ny,'ulong'); % data length in bytes 0250 nskip=0; % over-ride any nskip argument 0251 info(3)=8+wavlen(wavtype); % length of all header information 0252 info(4)=n; % number of samples (per channel) 0253 info(2)=n; % current file position (in samples) 0254 info(10)=rand(1); % seed for dither generation 0255 else 0256 info=filename; 0257 fid=info(1); 0258 fseek(fid,0,1); % go to end of file 0259 if nargin<5 || nskip<0 0260 nskip=info(2); % use previous high water mark 0261 end 0262 info(2)=n+nskip; % file position following this write operation (in samples) 0263 ny=nyd+nskip*ncy; % file position following this write operation (in bytes following header) 0264 if n && (info(2)>info(4)) % update high water mark 0265 if ~info(4) % if no data written previously 0266 fseek(fid,22,-1); fwrite(fid,nc,'ushort'); % update number of channels 0267 fseek(fid,28,-1); fwrite(fid,fs*ncy,'ulong'); % update bytes/second 0268 fwrite(fid,ncy,'ushort'); % update bytes/sample 0269 end 0270 fseek(fid,4,-1); fwrite(fid,wavlen(wavtype)+2*ceil(ny/2),'ulong'); % update RIFF length 0271 if factlen 0272 fseek(fid,wavlen(wavtype)-4-instlen,-1); fwrite(fid,n,'ulong'); % update FACT number of samples 0273 end 0274 fseek(fid,4+wavlen(wavtype),-1); fwrite(fid,ny,'ulong'); % update DATA length 0275 info(4)=info(2); 0276 end 0277 end 0278 info(5)=nc; 0279 0280 if n 0281 0282 if sc~='r' % 'r' = no scaling 0283 if sc=='s' % 's' = scale to peak signal 0284 pd=max(abs(d(:))); 0285 pd=pd+(pd==0); % scale to 1 if data is all zero 0286 elseif sc=='p' % 'p' = scale to +-1 = full scale 0287 pd=1; 0288 else % 'q' = scale to 0dBm 0289 if info(8)==7 % mu-law 0290 pd=2.03761563; 0291 else % A-law or anything else 0292 pd=2.03033976; 0293 end 0294 end 0295 if instlen 0296 info(11)=min(max(ceil(20*log10(pd)),-128),127); 0297 d=pk*10^(-0.05*info(11))*d; 0298 if fseek(fid,0,-1) % MATLAB V6.5 fails if this is omitted 0299 error('Cannot rewind file'); 0300 end 0301 if fseek(fid,info(3)-instlen+2,-1); 0302 error('Cannot seek to INST chunk gain byte'); 0303 end 0304 fwrite(fid,info(11),'schar'); % write the INST gain in dB 0305 else 0306 d=pk/pd*d; 0307 end 0308 end 0309 if fseek(fid,0,-1) % MATLAB V6.5 fails if this is omitted 0310 error('Cannot rewind file'); 0311 end 0312 if fseek(fid,info(3)+nskip*nc*info(6),-1) 0313 error('Cannot seek to byte %d in output file',info(3)+nskip*nc*info(6)); 0314 end 0315 if info(8)==3 % floating point 0316 if info(6)==4 0317 fwrite(fid,d,'float32'); 0318 else 0319 fwrite(fid,d,'float64'); 0320 end 0321 else % integer data 0322 if info(8)<6 % PCM 0323 if di=='n' 0324 d=round(d); 0325 else 0326 [d,info(10)]=ditherq(d,di,info(10)); 0327 end 0328 d=min(max(d,lo),hi)*pow2(1,8*info(6)-info(7)); % clip data and shift to most significant bits 0329 else % mu or A law 0330 z=0; 0331 if info(8) < 7 0332 d=lin2pcma(d,213,1); 0333 else 0334 d=lin2pcmu(d,1); 0335 end 0336 end 0337 if info(6)<3 0338 if info(6)<2 0339 fwrite(fid,d+z,'uchar'); 0340 else 0341 fwrite(fid,d,'short'); 0342 end 0343 else 0344 if info(6)<4 0345 d=d(:)'; 0346 d2=floor(d/65536); 0347 d=d-65536*d2; 0348 fwrite(fid,[rem(d,256); floor(d/256); d2+256*(d2<0)],'uchar'); 0349 else 0350 fwrite(fid,d,'long'); 0351 end 0352 end 0353 if rem(ny,2) % pad to an even number of bytes 0354 fwrite(fid,0,'uchar'); 0355 end 0356 end 0357 end 0358 if all(mode~='f') 0359 fclose(fid); 0360 end 0361 if nargout 0362 fidx=info; 0363 end