*/
# ifdef HAVE_CONFIG_H
# include "config.h"
# endif
# include "global.h"
# include <string.h>
# include "resample.h"
# include "mad.h"
static
mad_fixed_t const resample_table[9][9] = {
/* 48000 */ { MAD_F(0x10000000) /* 1.000000000 */,
MAD_F(0x116a3b36) /* 1.088435374 */,
MAD_F(0x18000000) /* 1.500000000 */,
MAD_F(0x20000000) /* 2.000000000 */,
MAD_F(0x22d4766c) /* 2.176870748 */,
MAD_F(0x30000000) /* 3.000000000 */,
MAD_F(0x40000000) /* 4.000000000 */,
MAD_F(0x45a8ecd8) /* 4.353741497 */,
MAD_F(0x60000000) /* 6.000000000 */ },
/* 44100 */ { MAD_F(0x0eb33333) /* 0.918750000 */,
MAD_F(0x10000000) /* 1.000000000 */,
MAD_F(0x160ccccd) /* 1.378125000 */,
MAD_F(0x1d666666) /* 1.837500000 */,
MAD_F(0x20000000) /* 2.000000000 */,
MAD_F(0x2c19999a) /* 2.756250000 */,
/*
* scalefactor table
* used in both Layer I and Layer II decoding
*/
static
mad_fixed_t const sf_table[64] = {
# include "sf_table.dat"
};
/* --- Layer I ------------------------------------------------------------- */
/* linear scaling table */
static
mad_fixed_t const linear_table[14] = {
MAD_F(0x15555555), /* 2^2 / (2^2 - 1) == 1.33333333333333 */
MAD_F(0x12492492), /* 2^3 / (2^3 - 1) == 1.14285714285714 */
MAD_F(0x11111111), /* 2^4 / (2^4 - 1) == 1.06666666666667 */
MAD_F(0x10842108), /* 2^5 / (2^5 - 1) == 1.03225806451613 */
MAD_F(0x10410410), /* 2^6 / (2^6 - 1) == 1.01587301587302 */
MAD_F(0x10204081), /* 2^7 / (2^7 - 1) == 1.00787401574803 */
MAD_F(0x10101010), /* 2^8 / (2^8 - 1) == 1.00392156862745 */
MAD_F(0x10080402), /* 2^9 / (2^9 - 1) == 1.00195694716243 */
MAD_F(0x10040100), /* 2^10 / (2^10 - 1) == 1.00097751710655 */
MAD_F(0x10020040), /* 2^11 / (2^11 - 1) == 1.00048851978505 */
MAD_F(0x10010010), /* 2^12 / (2^12 - 1) == 1.00024420024420 */
MAD_F(0x10008004), /* 2^13 / (2^13 - 1) == 1.00012208521548 */
MAD_F(0x10004001), /* 2^14 / (2^14 - 1) == 1.00006103888177 */
MAD_F(0x10002000) /* 2^15 / (2^15 - 1) == 1.00003051850948 */
};
/****************************************************************************
* Command-line arguments parsing. We use two methods and two command-line *
* formats depending on the system type. On unix system we apply the good *
* old getopt() method, other system are offered a really primitive options *
* interface. *
****************************************************************************/
static int ParseArgs(int argc, char * const argv[])
{
int DoPhoneFilter=0,
i;
double AmpFactor;
mad_fixed_t Amp=MAD_F_ONE;
#ifdef HAVE_GETOPT /* This version is for Unix systems. */
int Option;
/* Parse the command line. */
while((Option=getopt(argc,argv,"a:p"))!=-1)
switch(Option)
{
/* {5} Set the amplification/attenuation factor, expressed
* in dB.
*/
case 'a':
/* If the current linear amplification factor is not
* one (MAD_F_ONE) then is was already set. Setting it
* again is not permitted.
*/
if(Amp!=MAD_F_ONE)
{
fprintf(stderr,"%s: the amplification/attenuation factor "
"was set several times.\n",ProgName);
return(1);
}
/* The decibel value is converted to a linear factor.
* That factor is checked against the maximum value
* that can be stored in a mad_fixed_t. The upper
* bound is MAD_F_MAX, it is converted to a double
* value with mad_f_todouble() for comparison.
*/
AmpFactor=pow(10.,atof(optarg)/20);
if(AmpFactor>mad_f_todouble(MAD_F_MAX))
{
fprintf(stderr,"%s: amplification out of range.\n",
ProgName);
return(1);
}
/* Eventually the amplification factor is converted
* from double to fixed point with mad_f_tofixed().
*/
Amp=mad_f_tofixed(AmpFactor);
break;
/* {6} The output is filtered through a telephone wire. */
case 'p':
/* Only one occurrence of the option is permitted. */
if(DoPhoneFilter)
{
fprintf(stderr,"%s: the phone-line simulation option "
"was already set.\n",ProgName);
return(1);
}
/* The output will be filtered through a band-pass
* filter simulating a phone line transmission.
*/
DoPhoneFilter=1;
break;
/* Print usage guide for invalid options. */
case '?':
default:
PrintUsage();
return(1);
}
#else /* HAVE_GETOPT */ /* This other version is for non-Unix systems. */
/* Scan all command-line arguments. */
for(i=1;i<argc;i++)
{
/* Set the amplification factor if the current argument looks
* like a number. Look at the comment of the case marked {5}
* in the Unix section for details.
*/
if(*argv[i]=='+' || *argv[i]=='-' || isdigit(*argv[i]))
{
if(Amp!=MAD_F_ONE)
{
fprintf(stderr,"%s: the amplification/attenuation factor "
"was set several times.\n",ProgName);
return(1);
}
AmpFactor=pow(10.,atof(argv[i])/20);
if(AmpFactor>mad_f_todouble(MAD_F_MAX))
{
fprintf(stderr,"%s: amplification out of range.\n",
ProgName);
return(1);
}
Amp=mad_f_tofixed(AmpFactor);
}
else
/* Use the phone-like filter if the argument is the *
* 'phone' string. Look at the comment of the case marked
* {6} in the Unix section for details.
*/
if(strcmp(argv[i],"phone")==0)
{
if(DoPhoneFilter)
{
fprintf(stderr,"%s: the phone-line simulation option "
"was already set.\n",ProgName);
return(1);
}
DoPhoneFilter=1;
}
else
{
/* The argument is not a recognized one. Print the
* usage guidelines and stop there.
*/
PrintUsage();
return(1);
}
}
#endif /* HAVE_GETOPT */
/* Initialize the subband-domain filter coefficients to one if
* filtering is requested.
*/
if(Amp!=MAD_F_ONE || DoPhoneFilter)
for(i=0;i<32;i++)
Filter[i]=MAD_F_ONE;
/* The amplification/attenuation is applied to the subband-domain
* filter definition.
*/
if(Amp!=MAD_F_ONE)
{
DoFilter=1;
for(i=0;i<32;i++)
Filter[i]=Amp;
}
/* The telephone-like filter is applied to the subband-domain
* filter definition. All subbands are set to zero except bands 2
* to 6. This programs author has no access to the MPEG audio
* specification, he does not know the frequencies bands covered
* by the MPEG subbands.
*/
if(DoPhoneFilter)
{
DoFilter=1;
Filter[0]=MAD_F(0);
for(i=5;i<32;i++)
Filter[i]=MAD_F(0);
}
/* Command-line arguments are okay. */
return(0);
}
