www.pudn.com > MyPlayerbylqh.rar > Common.cpp

#include  
#include  
 
#include  
#include  
#include  
#include "mpg123.h" 
 
struct parameter 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 bitindex; 
uint8_t *wordpointer; 
uint8_t *pcm_sample; 
int pcm_point = 0; 
 
 
#define HDRCMPMASK 0xfffffd00 
 
 
 
//对文件头进行编译，并将相关信息写入帧结构中 
int head_check(unsigned long head) 
{ 
  if(head == 0xFF) 
	  return FALSE; 
  if ((head & 0xffe00000) != 0xffe00000) 
    return FALSE; 
  if (!((head >> 17) & 3)) 
    return FALSE; 
  if (((head >> 12) & 0xf) == 0xf) 
    return FALSE; 
  if (!((head >> 12) & 0xf)) 
    return FALSE; 
  if (((head >> 10) & 0x3) == 0x3) 
    return FALSE; 
  if (((head >> 19) & 1) == 1 && ((head >> 17) & 3) == 3 && ((head >> 16) & 1) == 1) 
    return FALSE; 
  if ((head & 0xffff0000) == 0xfffe0000) 
    return FALSE; 
   
  return TRUE; 
} 
 
 
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) { 
	   
	  return -1; 
	} 
 
	if(fr->mpeg25)  
	  fr->sampling_frequency = 6 + ((newhead>>10)&0x3); 
	else 
	  fr->sampling_frequency = ((newhead>>10)&0x3) + (fr->lsf*3); 
 
	fr->error_protection = ((newhead>>16)&0x1)^0x1; 
 
	if(fr->mpeg25)  
		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) { 
	  return -1; 
	} 
 
	switch(fr->lay) { 
	case 1: 
#if 0 
		fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?  
			(fr->mode_ext<<2)+4 : 32; 
#endif 
		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: 
#if 0 
		fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? 
			(fr->mode_ext<<2)+4 : fr->II_sblimit; 
#endif 
		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: 
#if 0 
		fr->do_layer = do_layer3; 
		if(fr->lsf) 
			ssize = (fr->stereo == 1) ? 9 : 17; 
		else 
			ssize = (fr->stereo == 1) ? 17 : 32; 
#endif 
 
		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: 
	  return -1; 
	} 
 
	return 0; 
} 
 
 
/** 
 * 
 **/ 
 
uint32_t getbits (int number_of_bits) 
{ 
	uint32_t rval; 
 
	if(!number_of_bits) 
		return 0; 
 
	rval = wordpointer[0]; 
	rval <<= 8; 
	rval |= wordpointer[1]; 
	rval <<= 8; 
	rval |= wordpointer[2]; 
	rval <<= bitindex; 
	rval &= 0xffffff; 
	bitindex += number_of_bits; 
 
	rval >>= (24-number_of_bits); 
 
	wordpointer += (bitindex>>3); 
	bitindex &= 7; 
 
	return rval; 
} 
 
 
/** 
 * 
 **/ 
 
uint16_t getbits_fast (int number_of_bits) 
{ 
	uint16_t rval; 
 
	rval = wordpointer[0]; 
	rval <<= 8;	 
	rval |= wordpointer[1]; 
	rval <<= bitindex; 
	rval &= 0xffff; 
	bitindex += number_of_bits; 
 
	rval >>= (16-number_of_bits); 
 
	wordpointer += (bitindex>>3); 
	bitindex &= 7; 
 
	return rval; 
} 
 
 
/** 
 * 
 **/ 
 
uint8_t get1bit(void) 
{ 
	uint8_t rval; 
	rval = *wordpointer << bitindex; 
 
	bitindex++; 
	wordpointer += (bitindex>>3); 
	bitindex &= 7; 
 
	return rval>>7; 
}