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/*
* PCM -> ADPCM routines
*
* based on work by Bitmaster and extended
*/
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <math.h>
#include "adpcm.h"
#define PCM_BUFFER_SIZE 128*28
short pcm_buffer[PCM_BUFFER_SIZE];
void SsAdpcm_find_predict( short *samples, double *d_samples, int *predict_nr, int *shift_factor);
void SsAdpcm_pack( double *d_samples, short *four_bit, int predict_nr, int shift_factor);
int SsAdpcmPack(void *pcm_data, void *adpcm_data, int sample_len,
int sample_fmt, int adpcm_len, int enable_looping,
int loop_start)
{
short *ptr;
unsigned char *pcm_data_c = pcm_data;
short *pcm_data_s = pcm_data;
unsigned char *adpcm_data_c = adpcm_data;
// short *adpcm_data_s = adpcm_data;
double d_samples[28];
short four_bit[28];
int predict_nr;
int shift_factor;
int flags;
int size;
int i, j, k;
unsigned char d;
// char s[4];
// int chunk_data;
// short e;
// short sample_size;
//unsigned char c;
int ap = 0;
int sp = 0;
/*printf("pcm_data = %x, adpcm_data = %x, len = %x, fmt = %x, alen = %x,"
"loop = %x\n", pcm_data, adpcm_data, sample_len, sample_fmt,
adpcm_len, enable_looping);
for(i=0;i<8;i++)
printf("I[%d] = %x\n", i, pcm_data_c[i]);*/
//if(enable_looping)
// flags = 6;
// else
flags = 0;
while( sample_len > 0 ) {
size = ( sample_len >= PCM_BUFFER_SIZE ) ? PCM_BUFFER_SIZE : sample_len;
if(sample_fmt == FMT_U8)
{
for(i = 0; i < size; i++)
{
//c = fgetc(fp);
pcm_buffer[i] = *(pcm_data_c++);
pcm_buffer[i] ^= 0x80;
pcm_buffer[i] <<= 8;
}
}
else if(sample_fmt == FMT_S16)
{
//fread( wave, sizeof( short ), size, fp );
memcpy(pcm_buffer, pcm_data_s, size * sizeof(short));
pcm_data_s += size;
}
else
{
printf("%s, line %d: Unknown source sample format!, id=%d\n",__FUNCTION__,__LINE__,sample_fmt);
return 0;
}
i = size / 28;
if ( size % 28 ) {
for ( j = size % 28; j < 28; j++ )
pcm_buffer[28*i+j] = 0;
i++;
}
for ( j = 0; j < i; j++ ) { // pack 28 samples
if ( sample_len < 28 && enable_looping == 0)
flags = 1;
if(enable_looping)
{
if(((loop_start/28)*28) == sp)
flags = 6;
else
flags = 2;
}
ptr = pcm_buffer + j * 28;
SsAdpcm_find_predict( ptr, d_samples, &predict_nr, &shift_factor );
SsAdpcm_pack( d_samples, four_bit, predict_nr, shift_factor );
d = ( predict_nr << 4 ) | shift_factor;
// fputc( d, vag );
adpcm_data_c[ap++] = d;
if(ap>=adpcm_len) goto adpcm_too_big;
// fputc( flags, vag );
adpcm_data_c[ap++] = flags;
if(ap>=adpcm_len) goto adpcm_too_big;
for ( k = 0; k < 28; k += 2 ) {
d = ( ( four_bit[k+1] >> 8 ) & 0xf0 ) | ( ( four_bit[k] >> 12 ) & 0xf );
// fputc( d, vag );
adpcm_data_c[ap++] = d;
if(ap>=adpcm_len) goto adpcm_too_big;
}
sample_len -= 28;
sp += 28;
}
}
// fputc( ( predict_nr << 4 ) | shift_factor, vag );
adpcm_data_c[ap++] = ( predict_nr << 4 ) | shift_factor;
if(ap>=adpcm_len) goto adpcm_too_big;
if(enable_looping)
// fputc(3, vag);
adpcm_data_c[ap++] = 3;
else
// fputc( 7, vag ); // end flag
adpcm_data_c[ap++] = 7;
if(ap>=adpcm_len) goto adpcm_too_big;
for ( i = 0; i < 14; i++ )
// fputc( 0, vag );
adpcm_data_c[ap++] = 0;
if(ap>=adpcm_len) goto adpcm_too_big;
return ap;
adpcm_too_big:
printf("%s: Resulting ADPCM data would have been larger than the output array length! Exiting %s.\n", __FUNCTION__, __FUNCTION__);
return 0;
}
void SsAdpcm_find_predict( short *samples, double *d_samples, int *predict_nr, int *shift_factor )
{
int i, j;
double buffer[28][5];
double min = 1e10;
double max[5];
double ds;
int min2;
int shift_mask;
static double _s_1 = 0.0; // s[t-1]
static double _s_2 = 0.0; // s[t-2]
double s_0, s_1, s_2;
double f[5][2] = { { 0.0, 0.0 },
{ -60.0 / 64.0, 0.0 },
{ -115.0 / 64.0, 52.0 / 64.0 },
{ -98.0 / 64.0, 55.0 / 64.0 },
{ -122.0 / 64.0, 60.0 / 64.0 } };
for ( i = 0; i < 5; i++ ) {
max[i] = 0.0;
s_1 = _s_1;
s_2 = _s_2;
for ( j = 0; j < 28; j ++ ) {
s_0 = (double) samples[j]; // s[t-0]
if ( s_0 > 30719.0 )
s_0 = 30719.0;
if ( s_0 < - 30720.0 )
s_0 = -30720.0;
ds = s_0 + s_1 * f[i][0] + s_2 * f[i][1];
buffer[j][i] = ds;
if ( fabs( ds ) > max[i] )
max[i] = fabs( ds );
// printf( "%+5.2f\n", s2 );
s_2 = s_1; // new s[t-2]
s_1 = s_0; // new s[t-1]
}
if ( max[i] < min ) {
min = max[i];
*predict_nr = i;
}
if ( min <= 7 ) {
*predict_nr = 0;
break;
}
}
// store s[t-2] and s[t-1] in a static variable
// these than used in the next function call
_s_1 = s_1;
_s_2 = s_2;
for ( i = 0; i < 28; i++ )
d_samples[i] = buffer[i][*predict_nr];
// if ( min > 32767.0 )
// min = 32767.0;
min2 = ( int ) min;
shift_mask = 0x4000;
*shift_factor = 0;
while( *shift_factor < 12 ) {
if ( shift_mask & ( min2 + ( shift_mask >> 3 ) ) )
break;
(*shift_factor)++;
shift_mask = shift_mask >> 1;
}
}
void SsAdpcm_pack( double *d_samples, short *four_bit, int predict_nr, int shift_factor )
{
static double f[5][2] = { { 0.0, 0.0 },
{ -60.0 / 64.0, 0.0 },
{ -115.0 / 64.0, 52.0 / 64.0 },
{ -98.0 / 64.0, 55.0 / 64.0 },
{ -122.0 / 64.0, 60.0 / 64.0 } };
double ds;
int di;
double s_0;
static double s_1 = 0.0;
static double s_2 = 0.0;
int i;
for ( i = 0; i < 28; i++ ) {
s_0 = d_samples[i] + s_1 * f[predict_nr][0] + s_2 * f[predict_nr][1];
ds = s_0 * (double) ( 1 << shift_factor );
di = ( (int) ds + 0x800 ) & 0xfffff000;
if ( di > 32767 )
di = 32767;
if ( di < -32768 )
di = -32768;
four_bit[i] = (short) di;
di = di >> shift_factor;
s_2 = s_1;
s_1 = (double) di - s_0;
}
}
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