libst.c

linux下录音程序

/* libst.c - portable sound tools library
*/

#include "libst.h"

#ifndef FAST_ULAW_CONVERSION

/*
** This routine converts from linear to ulaw.
**
** Craig Reese: IDA/Supercomputing Research Center
** Joe Campbell: Department of Defense
** 29 September 1989
**
** References:
** 1) CCITT Recommendation G.711  (very difficult to follow)
** 2) "A New Digital Technique for Implementation of Any
**     Continuous PCM Companding Law," Villeret, Michel,
**     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
**     1973, pg. 11.12-11.17
** 3) MIL-STD-188-113,"Interoperability and Performance Standards
**     for Analog-to_Digital Conversion Techniques,"
**     17 February 1987
**
** Input: Signed 16 bit linear sample
** Output: 8 bit ulaw sample
*/

#undef ZEROTRAP      /* turn off the trap as per the MIL-STD */
#define uBIAS 0x84   /* define the add-in bias for 16 bit samples */
#define uCLIP 32635
#define ACLIP 31744

unsigned char
st_linear_to_ulaw( sample )
int sample;
    {
    static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
                               4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
                               5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
                               5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
                               6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                               6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                               6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                               6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                               7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7};
    int sign, exponent, mantissa;
    unsigned char ulawbyte;

    /* Get the sample into sign-magnitude. */
    sign = (sample >> 8) & 0x80;		/* set aside the sign */
    if ( sign != 0 ) sample = -sample;		/* get magnitude */
    if ( sample > uCLIP ) sample = uCLIP;		/* clip the magnitude */

    /* Convert from 16 bit linear to ulaw. */
    sample = sample + uBIAS;
    exponent = exp_lut[( sample >> 7 ) & 0xFF];
    mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F;
    ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa );
#ifdef ZEROTRAP
    if ( ulawbyte == 0 ) ulawbyte = 0x02;	/* optional CCITT trap */
#endif

    return ulawbyte;
    }

/*
** This routine converts from ulaw to 16 bit linear.
**
** Craig Reese: IDA/Supercomputing Research Center
** 29 September 1989
**
** References:
** 1) CCITT Recommendation G.711  (very difficult to follow)
** 2) MIL-STD-188-113,"Interoperability and Performance Standards
**     for Analog-to_Digital Conversion Techniques,"
**     17 February 1987
**
** Input: 8 bit ulaw sample
** Output: signed 16 bit linear sample
*/

int
st_ulaw_to_linear( ulawbyte )
unsigned char ulawbyte;
    {
    static int exp_lut[8] = { 0, 132, 396, 924, 1980, 4092, 8316, 16764 };
    int sign, exponent, mantissa, sample;

    ulawbyte = ~ ulawbyte;
    sign = ( ulawbyte & 0x80 );
    exponent = ( ulawbyte >> 4 ) & 0x07;
    mantissa = ulawbyte & 0x0F;
    sample = exp_lut[exponent] + ( mantissa << ( exponent + 3 ) );
    if ( sign != 0 ) sample = -sample;

    return sample;
    }

#else

unsigned char ulaw_comp_table[16384] = {
	0xff,0xfe,0xfe,0xfd,0xfd,0xfc,0xfc,0xfb,
	0xfb,0xfa,0xfa,0xf9,0xf9,0xf8,0xf8,0xf7,
	0xf7,0xf6,0xf6,0xf5,0xf5,0xf4,0xf4,0xf3,
	0xf3,0xf2,0xf2,0xf1,0xf1,0xf0,0xf0,0xef,
	0xef,0xef,0xef,0xee,0xee,0xee,0xee,0xed,
	0xed,0xed,0xed,0xec,0xec,0xec,0xec,0xeb,
	0xeb,0xeb,0xeb,0xea,0xea,0xea,0xea,0xe9,
	0xe9,0xe9,0xe9,0xe8,0xe8,0xe8,0xe8,0xe7,
	0xe7,0xe7,0xe7,0xe6,0xe6,0xe6,0xe6,0xe5,
	0xe5,0xe5,0xe5,0xe4,0xe4,0xe4,0xe4,0xe3,
	0xe3,0xe3,0xe3,0xe2,0xe2,0xe2,0xe2,0xe1,
	0xe1,0xe1,0xe1,0xe0,0xe0,0xe0,0xe0,0xdf,
	0xdf,0xdf,0xdf,0xdf,0xdf,0xdf,0xdf,0xde,
	0xde,0xde,0xde,0xde,0xde,0xde,0xde,0xdd,
	0xdd,0xdd,0xdd,0xdd,0xdd,0xdd,0xdd,0xdc,
	0xdc,0xdc,0xdc,0xdc,0xdc,0xdc,0xdc,0xdb,
	0xdb,0xdb,0xdb,0xdb,0xdb,0xdb,0xdb,0xda,
	0xda,0xda,0xda,0xda,0xda,0xda,0xda,0xd9,
	0xd9,0xd9,0xd9,0xd9,0xd9,0xd9,0xd9,0xd8,
	0xd8,0xd8,0xd8,0xd8,0xd8,0xd8,0xd8,0xd7,
	0xd7,0xd7,0xd7,0xd7,0xd7,0xd7,0xd7,0xd6,
	0xd6,0xd6,0xd6,0xd6,0xd6,0xd6,0xd6,0xd5,
	0xd5,0xd5,0xd5,0xd5,0xd5,0xd5,0xd5,0xd4,
	0xd4,0xd4,0xd4,0xd4,0xd4,0xd4,0xd4,0xd3,
	0xd3,0xd3,0xd3,0xd3,0xd3,0xd3,0xd3,0xd2,
	0xd2,0xd2,0xd2,0xd2,0xd2,0xd2,0xd2,0xd1,
	0xd1,0xd1,0xd1,0xd1,0xd1,0xd1,0xd1,0xd0,
	0xd0,0xd0,0xd0,0xd0,0xd0,0xd0,0xd0,0xcf,
	0xcf,0xcf,0xcf,0xcf,0xcf,0xcf,0xcf,0xcf,
	0xcf,0xcf,0xcf,0xcf,0xcf,0xcf,0xcf,0xce,
	0xce,0xce,0xce,0xce,0xce,0xce,0xce,0xce,
	0xce,0xce,0xce,0xce,0xce,0xce,0xce,0xcd,
	0xcd,0xcd,0xcd,0xcd,0xcd,0xcd,0xcd,0xcd,
	0xcd,0xcd,0xcd,0xcd,0xcd,0xcd,0xcd,0xcc,
	0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,
	0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcb,
	0xcb,0xcb,0xcb,0xcb,0xcb,0xcb,0xcb,0xcb,
	0xcb,0xcb,0xcb,0xcb,0xcb,0xcb,0xcb,0xca,
	0xca,0xca,0xca,0xca,0xca,0xca,0xca,0xca,
	0xca,0xca,0xca,0xca,0xca,0xca,0xca,0xc9,
	0xc9,0xc9,0xc9,0xc9,0xc9,0xc9,0xc9,0xc9,
	0xc9,0xc9,0xc9,0xc9,0xc9,0xc9,0xc9,0xc8,
	0xc8,0xc8,0xc8,0xc8,0xc8,0xc8,0xc8,0xc8,
	0xc8,0xc8,0xc8,0xc8,0xc8,0xc8,0xc8,0xc7,
	0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,
	0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,0xc6,
	0xc6,0xc6,0xc6,0xc6,0xc6,0xc6,0xc6,0xc6,
	0xc6,0xc6,0xc6,0xc6,0xc6,0xc6,0xc6,0xc5,
	0xc5,0xc5,0xc5,0xc5,0xc5,0xc5,0xc5,0xc5,
	0xc5,0xc5,0xc5,0xc5,0xc5,0xc5,0xc5,0xc4,
	0xc4,0xc4,0xc4,0xc4,0xc4,0xc4,0xc4,0xc4,
	0xc4,0xc4,0xc4,0xc4,0xc4,0xc4,0xc4,0xc3,
	0xc3,0xc3,0xc3,0xc3,0xc3,0xc3,0xc3,0xc3,
	0xc3,0xc3,0xc3,0xc3,0xc3,0xc3,0xc3,0xc2,
	0xc2,0xc2,0xc2,0xc2,0xc2,0xc2,0xc2,0xc2,
	0xc2,0xc2,0xc2,0xc2,0xc2,0xc2,0xc2,0xc1,
	0xc1,0xc1,0xc1,0xc1,0xc1,0xc1,0xc1,0xc1,
	0xc1,0xc1,0xc1,0xc1,0xc1,0xc1,0xc1,0xc0,
	0xc0,0xc0,0xc0,0xc0,0xc0,0xc0,0xc0,0xc0,
	0xc0,0xc0,0xc0,0xc0,0xc0,0xc0,0xc0,0xbf,
	0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,
	0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,
	0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,
	0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbf,0xbe,
	0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,
	0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,
	0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,
	0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbe,0xbd,
	0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,
	0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,
	0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,
	0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbd,0xbc,
	0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,
	0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,
	0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,
	0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbc,0xbb,
	0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,
	0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,
	0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,
	0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xbb,0xba,
	0xba,0xba,0xba,0xba,0xba,0xba,0xba,0xba,
	0xba,0xba,0xba,0xba,0xba,0xba,0xba,0xba,
	0xba,0xba,0xba,0xba,0xba,0xba,0xba,0xba,
	0xba,0xba,0xba,0xba,0xba,0xba,0xba,0xb9,
	0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,
	0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,
	0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,
	0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb9,0xb8,
	0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,
	0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,
	0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,
	0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb8,0xb7,
	0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,
	0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,
	0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,
	0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb7,0xb6,
	0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,
	0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,
	0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,
	0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb6,0xb5,
	0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,
	0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,
	0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,
	0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb5,0xb4,
	0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,
	0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,
	0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,
	0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb4,0xb3,
	0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,
	0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,
	0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,
	0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb3,0xb2,
	0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,
	0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,
	0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,
	0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb2,0xb1,
	0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,
	0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,
	0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,
	0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb1,0xb0,
	0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,
	0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,
	0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,
	0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xb0,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,
	0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xaf,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xae,
	0xae,0xae,0xae,0xae,0xae,0xae,0xae,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xad,
	0xad,0xad,0xad,0xad,0xad,0xad,0xad,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xac,
	0xac,0xac,0xac,0xac,0xac,0xac,0xac,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xab,
	0xab,0xab,0xab,0xab,0xab,0xab,0xab,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,
	0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,
	0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa9,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,
	0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa8,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,
	0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa7,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,
	0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa6,0xa5,
	0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,
	0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,
	0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,
	0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,