common.c

ARM MP3解码源代码1.0 有完整的项目文件

/***********************************************
copyright by Haia Tech
www.haia2004.com
************************************************/



#include <string.h>
//#include <stdlib.h>
#include <math.h>
#include "common.h"
 
//extern FILE *file_p; 
extern frame_params fr_ps; 
extern unsigned int   frameNum;
Bit_stream_struc  bs;
unsigned short *mp3_dat;

double  s_freq[4] = {44.1, 48, 32, 0};
char *mode_names[4] = { "stereo", "j-stereo", "dual-ch", "single-ch" };

char *layer_names[3] = { "I", "II", "III" };

int bitrate[3][15] = {
	{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}
};

unsigned short buffer[BUFFER_SIZE];


/* open the device to read the bit stream from it */
void open_bit_stream_r()
{
	bs.buf=buffer;
	bs.read_ptr=0;
	bs.write_ptr=0;
	bs.bit_len=16;
	bs.totbit=0;
	bs.eof = FALSE;
	bs.eobs = FALSE;
	quest_stream(&bs.write_ptr);
}


/*return the status of the bit stream*/
/* returns 1 if end of bit stream was reached */
/* returns 0 if end of bit stream was not reached */

int mask[8]={0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80};

int seek_sync(unsigned int sync)
{
	unsigned int aligning;
	unsigned int val;

    aligning = bs.totbit%ALIGNING;
    if (aligning)
		getbit((int)(ALIGNING-aligning));   //