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#include <ctype.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "mpg123.h"
struct parameter mpg123_param = { 1 , 1 , 0 , 0 };
int tabsel_123[2][3][16] = {
{ {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,},
{0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,},
{0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,} },
{ {0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,} }
};
long freqs[9] = { 44100, 48000, 32000,
22050, 24000, 16000 ,
11025 , 12000 , 8000 };
int mpg123_bitindex;
unsigned char *mpg123_wordpointer;
unsigned char *pcm_sample;
int pcm_point = 0;
#define HDRCMPMASK 0xfffffd00
/*
* the code a header and write the information
* into the frame structure
*/
int decode_header(struct frame *fr,unsigned long newhead)
{
if( newhead & (1<<20) ) {
fr->lsf = (newhead & (1<<19)) ? 0x0 : 0x1;
fr->mpeg25 = 0;
}
else {
fr->lsf = 1;
fr->mpeg25 = 1;
}
fr->lay = 4-((newhead>>17)&3);
if( ((newhead>>10)&0x3) == 0x3) {
fprintf(stderr,"Stream error\n");
abort();
}
if(fr->mpeg25) {
fr->sampling_frequency = 6 + ((newhead>>10)&0x3);
}
else {
/*int dummy;*/
fr->sampling_frequency = ((newhead>>10)&0x3) + (fr->lsf*3);
/*
dummy = (newhead>>10)&0x3;
switch (dummy) {
case 0:
fr->sample_rate = 44100;
break;
case 1:
fr->sample_rate = 48000;
break;
case 2:
fr->sample_rate = 32000;
break;
case 3:
fprintf (stderr, "invalid sampling rate\n");
fr->sample_rate = 44100;
break;
}*/
fr->sample_rate = freqs[fr->sampling_frequency];
}
fr->error_protection = ((newhead>>16)&0x1)^0x1;
if(fr->mpeg25) /* allow Bitrate change for 2.5 ... */
fr->bitrate_index = ((newhead>>12)&0xf);
fr->bitrate_index = ((newhead>>12)&0xf);
fr->padding = ((newhead>>9)&0x1);
fr->extension = ((newhead>>8)&0x1);
fr->mode = ((newhead>>6)&0x3);
fr->mode_ext = ((newhead>>4)&0x3);
fr->copyright = ((newhead>>3)&0x1);
fr->original = ((newhead>>2)&0x1);
fr->emphasis = newhead & 0x3;
fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;
if(!fr->bitrate_index)
{
fprintf(stderr,"Free format not supported.\n");
return (0);
}
switch(fr->lay)
{
case 1:
fr->framesize = (long) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize = ((fr->framesize+fr->padding)<<2)-4;
break;
case 2:
fr->framesize = (long) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize += fr->padding - 4;
break;
case 3:
fr->framesize = (long) tabsel_123[fr->lsf][2][fr->bitrate_index] * 144000;
fr->framesize /= freqs[fr->sampling_frequency]<<(fr->lsf);
fr->framesize = fr->framesize + fr->padding - 4;
break;
default:
fprintf(stderr,"Sorry, unknown layer type.\n");
return (0);
}
return 1;
}
unsigned int getbits(int number_of_bits)
{
unsigned long rval;
if(!number_of_bits)
return 0;
{
rval = mpg123_wordpointer[0];
rval <<= 8;
rval |= mpg123_wordpointer[1];
rval <<= 8;
rval |= mpg123_wordpointer[2];
rval <<= mpg123_bitindex;
rval &= 0xffffff;
mpg123_bitindex += number_of_bits;
rval >>= (24-number_of_bits);
mpg123_wordpointer += (mpg123_bitindex>>3);
mpg123_bitindex &= 7;
}
return rval;
}
unsigned int getbits_fast(int number_of_bits)
{
unsigned long rval;
{
rval = mpg123_wordpointer[0];
rval <<= 8;
rval |= mpg123_wordpointer[1];
rval <<= mpg123_bitindex;
rval &= 0xffff;
mpg123_bitindex += number_of_bits;
rval >>= (16-number_of_bits);
mpg123_wordpointer += (mpg123_bitindex>>3);
mpg123_bitindex &= 7;
}
return rval;
}
unsigned int get1bit(void)
{
unsigned char rval;
rval = *mpg123_wordpointer << mpg123_bitindex;
mpg123_bitindex++;
mpg123_wordpointer += (mpg123_bitindex>>3);
mpg123_bitindex &= 7;
return rval>>7;
}
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