cinelerra-5.1/cinelerra/filebaseulaw.C

   1
   2 /*
   3  * CINELERRA
   4  * Copyright (C) 2008 Adam Williams <broadcast at earthling dot net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include "assets.h"
  23 #include "byteorder.h"
  24 #include "file.h"
  25 #include "filebase.h"
  26 #include "sizes.h"
  27
  28 // ======================================= ulaw codecs
  29
  30 float FileBase::ulawtofloat(char ulaw)
  31 {
  32 //printf("%f\n", ulawtofloat_ptr[ulaw]);
  33         return ulawtofloat_ptr[(unsigned char)ulaw];
  34 }
  35
  36 char FileBase::floattoulaw(float value)
  37 {
  38         return floattoulaw_ptr[(int)(value * 32767)];
  39 }
  40
  41 // turn off the trap as per the MIL-STD
  42 #undef ZEROTRAP
  43 // define the add-in bias for 16 bit samples
  44 #define uBIAS 0x84
  45 #define uCLIP 32635
  46
  47 int FileBase::generate_ulaw_tables()
  48 {
  49         if( !ulawtofloat_table )
  50         {
  51                 static int exp_lut[8] = {
  52                         0, 132, 396, 924, 1980, 4092, 8316, 16764
  53                 };
  54                 int sign, exponent, mantissa, sample;
  55                 unsigned char ulawbyte;
  56
  57                 ulawtofloat_table = new float[256];
  58                 ulawtofloat_ptr = ulawtofloat_table;
  59                 for(int i = 0; i < 256; i++)
  60                 {
  61                         ulawbyte = (unsigned char)i;
  62                         ulawbyte = ~ ulawbyte;
  63                         sign = ( ulawbyte & 0x80 );
  64                         exponent = ( ulawbyte >> 4 ) & 0x07;
  65                         mantissa = ulawbyte & 0x0F;
  66                         sample = exp_lut[exponent] + ( mantissa << ( exponent + 3 ) );
  67                         if ( sign != 0 ) sample = -sample;
  68                         ulawtofloat_ptr[(int)i] = (float)sample / 32768;
  69                 }
  70         }
  71
  72         if( !floattoulaw_table )
  73         {
  74                 int sign, exponent, mantissa;
  75                 unsigned char ulawbyte;
  76                 int sample;
  77                 int exp_lut[256] = {
  78                         0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
  79                         4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
  80                         5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
  81                         5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
  82                         6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  83                         6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  84                         6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  85                         6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  86                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  87                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  88                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  89                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  90                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  91                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  92                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  93                         7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  94                 };
  95
  96                 floattoulaw_table = new unsigned char[65536];
  97                 floattoulaw_ptr = floattoulaw_table + 32768;
  98
  99                 for(int i = -32768; i < 32768; i++)
 100                 {
 101                         sample = i;
 102 // Get the sample into sign-magnitude.
 103                         sign = (sample >> 8) & 0x80;            // set aside the sign
 104                         if ( sign != 0 ) sample = -sample;              // get magnitude
 105                         if ( sample > uCLIP ) sample = uCLIP;           // clip the magnitude
 106 // Convert from 16 bit linear to ulaw.
 107                         sample = sample + uBIAS;
 108                         exponent = exp_lut[( sample >> 7 ) & 0xFF];
 109                         mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F;
 110                         ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa );
 111 #ifdef ZEROTRAP
 112                         if ( ulawbyte == 0 ) ulawbyte = 0x02;   /* optional CCITT trap */
 113 #endif
 114                         floattoulaw_ptr[i] = ulawbyte;
 115                 }
 116         }
 117         return 0;
 118 }
 119
 120 int FileBase::delete_ulaw_tables()
 121 {
 122         if(floattoulaw_table) delete [] floattoulaw_table;
 123         if(ulawtofloat_table) delete [] ulawtofloat_table;
 124         floattoulaw_table = 0;
 125         ulawtofloat_table = 0;
 126         return 0;
 127 }