interpretor/libsndfile-1.0.25/tests/ulaw_test.c

   1 /*
   2 ** Copyright (C) 1999-2011 Erik de Castro Lopo <erikd@mega-nerd.com>
   3 **
   4 ** This program is free software; you can redistribute it and/or modify
   5 ** it under the terms of the GNU General Public License as published by
   6 ** the Free Software Foundation; either version 2 of the License, or
   7 ** (at your option) any later version.
   8 **
   9 ** This program is distributed in the hope that it will be useful,
  10 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 ** GNU General Public License for more details.
  13 **
  14 ** You should have received a copy of the GNU General Public License
  15 ** along with this program; if not, write to the Free Software
  16 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17 */
  18
  19 #include "sfconfig.h"
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #if HAVE_UNISTD_H
  26 #include <unistd.h>
  27 #endif
  28
  29 #include <sndfile.h>
  30
  31 #include "utils.h"
  32
  33 #define BUFFER_SIZE             (65536)
  34
  35 static unsigned char    ulaw_encode (int sample) ;
  36 static int                              ulaw_decode (unsigned int ulawbyte) ;
  37
  38 static  short                   short_buffer [BUFFER_SIZE] ;
  39 static  unsigned char   ulaw_buffer [BUFFER_SIZE] ;
  40
  41 int
  42 main (void)
  43 {       SNDFILE         *file ;
  44         SF_INFO         sfinfo ;
  45         const char      *filename ;
  46         int                     k ;
  47
  48         print_test_name ("ulaw_test", "encoder") ;
  49
  50         filename = "test.raw" ;
  51
  52         sf_info_setup (&sfinfo, SF_FORMAT_RAW | SF_FORMAT_ULAW, 44100, 1) ;
  53
  54         if ((file = sf_open (filename, SFM_WRITE, &sfinfo)) == NULL)
  55         {       printf ("sf_open_write failed with error : ") ;
  56                 fflush (stdout) ;
  57                 puts (sf_strerror (NULL)) ;
  58                 exit (1) ;
  59                 } ;
  60
  61         /* Generate a file containing all possible 16 bit sample values
  62         ** and write it to disk as ulaw encoded.frames.
  63         */
  64
  65         for (k = 0 ; k < 0x10000 ; k++)
  66                 short_buffer [k] = k & 0xFFFF ;
  67
  68         sf_write_short (file, short_buffer, BUFFER_SIZE) ;
  69         sf_close (file) ;
  70
  71         /* Now open that file and compare the ulaw encoded sample values
  72         ** with what they should be.
  73         */
  74
  75         if ((file = sf_open (filename, SFM_READ, &sfinfo)) == NULL)
  76         {       printf ("sf_open_write failed with error : ") ;
  77                 puts (sf_strerror (NULL)) ;
  78                 exit (1) ;
  79                 } ;
  80
  81         check_log_buffer_or_die (file, __LINE__) ;
  82
  83         if (sf_read_raw (file, ulaw_buffer, BUFFER_SIZE) != BUFFER_SIZE)
  84         {       printf ("sf_read_raw : ") ;
  85                 puts (sf_strerror (file)) ;
  86                 exit (1) ;
  87                 } ;
  88
  89         for (k = 0 ; k < 0x10000 ; k++)
  90                 if (ulaw_encode (short_buffer [k]) != ulaw_buffer [k])
  91                 {       printf ("Encoder error : sample #%d (0x%02X should be 0x%02X)\n", k, ulaw_buffer [k], ulaw_encode (short_buffer [k])) ;
  92                         exit (1) ;
  93                         } ;
  94
  95         sf_close (file) ;
  96
  97         puts ("ok") ;
  98
  99         print_test_name ("ulaw_test", "decoder") ;
 100
 101         /* Now generate a file containing all possible 8 bit encoded
 102         ** sample values and write it to disk as ulaw encoded.frames.
 103         */
 104
 105         if (! (file = sf_open (filename, SFM_WRITE, &sfinfo)))
 106         {       printf ("sf_open_write failed with error : ") ;
 107                 puts (sf_strerror (NULL)) ;
 108                 exit (1) ;
 109                 } ;
 110
 111         for (k = 0 ; k < 256 ; k++)
 112                 ulaw_buffer [k] = k & 0xFF ;
 113
 114         sf_write_raw (file, ulaw_buffer, 256) ;
 115         sf_close (file) ;
 116
 117         /* Now open that file and compare the ulaw decoded sample values
 118         ** with what they should be.
 119         */
 120
 121         if (! (file = sf_open (filename, SFM_READ, &sfinfo)))
 122         {       printf ("sf_open_write failed with error : ") ;
 123                 puts (sf_strerror (NULL)) ;
 124                 exit (1) ;
 125                 } ;
 126
 127         check_log_buffer_or_die (file, __LINE__) ;
 128
 129         if (sf_read_short (file, short_buffer, 256) != 256)
 130         {       printf ("sf_read_short : ") ;
 131                 puts (sf_strerror (file)) ;
 132                 exit (1) ;
 133                 } ;
 134
 135
 136         for (k = 0 ; k < 256 ; k++)
 137                 if (short_buffer [k] != ulaw_decode (ulaw_buffer [k]))
 138                 {       printf ("Decoder error : sample #%d (0x%04X should be 0x%04X)\n", k, short_buffer [k], ulaw_decode (ulaw_buffer [k])) ;
 139                         exit (1) ;
 140                         } ;
 141
 142         sf_close (file) ;
 143
 144         puts ("ok") ;
 145
 146         unlink (filename) ;
 147
 148         return 0 ;
 149 } /* main */
 150
 151
 152 /*=================================================================================
 153 **      The following routines came from the sox-12.15 (Sound eXcahcnge) distribution.
 154 **
 155 **      This code is not compiled into libsndfile. It is only used to test the
 156 **      libsndfile lookup tables for correctness.
 157 **
 158 **      I have included the original authors comments.
 159 */
 160
 161 /*
 162 ** This routine converts from linear to ulaw.
 163 **
 164 ** Craig Reese: IDA/Supercomputing Research Center
 165 ** Joe Campbell: Department of Defense
 166 ** 29 September 1989
 167 **
 168 ** References:
 169 ** 1) CCITT Recommendation G.711  (very difficult to follow)
 170 ** 2) "A New Digital Technique for Implementation of Any
 171 **     Continuous PCM Companding Law," Villeret, Michel,
 172 **     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
 173 **     1973, pg. 11.12-11.17
 174 ** 3) MIL-STD-188-113,"Interoperability and Performance Standards
 175 **     for Analog-to_Digital Conversion Techniques,"
 176 **     17 February 1987
 177 **
 178 ** Input: Signed 16 bit linear sample
 179 ** Output: 8 bit ulaw sample
 180 */
 181
 182 #define uBIAS 0x84              /* define the add-in bias for 16 bit.frames */
 183 #define uCLIP 32635
 184
 185 static
 186 unsigned char ulaw_encode (int sample)
 187 {       static int exp_lut [256] =
 188         {       0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
 189                 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
 190                 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
 191                 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
 192                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
 193                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
 194                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
 195                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
 196                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 197                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 198                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 199                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 200                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 201                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 202                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
 203                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
 204                 } ;
 205
 206     int sign, exponent, mantissa ;
 207     unsigned char ulawbyte ;
 208
 209     /* Get the sample into sign-magnitude. */
 210     sign = (sample >> 8) & 0x80 ;                                       /* set aside the sign */
 211     if ( sign != 0 )
 212                 sample = -sample ;                                                      /* get magnitude */
 213     if ( sample > uCLIP )
 214                 sample = uCLIP ;                                                        /* clip the magnitude */
 215
 216     /* Convert from 16 bit linear to ulaw. */
 217     sample = sample + uBIAS ;
 218     exponent = exp_lut [( sample >> 7 ) & 0xFF] ;
 219     mantissa = (sample >> ( exponent + 3 ) ) & 0x0F ;
 220     ulawbyte = ~ (sign | ( exponent << 4 ) | mantissa) ;
 221
 222         return ulawbyte ;
 223 } /* ulaw_encode */
 224
 225
 226 /*
 227 ** This routine converts from ulaw to 16 bit linear.
 228 **
 229 ** Craig Reese: IDA/Supercomputing Research Center
 230 ** 29 September 1989
 231 **
 232 ** References:
 233 ** 1) CCITT Recommendation G.711  (very difficult to follow)
 234 ** 2) MIL-STD-188-113,"Interoperability and Performance Standards
 235 **     for Analog-to_Digital Conversion Techniques,"
 236 **     17 February 1987
 237 **
 238 ** Input: 8 bit ulaw sample
 239 ** Output: signed 16 bit linear sample
 240 */
 241
 242 static
 243 int ulaw_decode (unsigned int ulawbyte)
 244 {       static int exp_lut [8] = { 0, 132, 396, 924, 1980, 4092, 8316, 16764 } ;
 245     int sign, exponent, mantissa, sample ;
 246
 247     ulawbyte = ~ ulawbyte ;
 248     sign = (ulawbyte & 0x80) ;
 249     exponent = (ulawbyte >> 4) & 0x07 ;
 250     mantissa = ulawbyte & 0x0F ;
 251     sample = exp_lut [exponent] + (mantissa << (exponent + 3)) ;
 252     if (sign != 0)
 253                 sample = -sample ;
 254
 255     return sample ;
 256 } /* ulaw_decode */
 257