layer3.c

xmms-1.2.10.tar.gz学习使用的就下吧

/* 
 * Mpeg Layer-3 audio decoder 
 * --------------------------
 * copyright (c) 1995-1999 by Michael Hipp.
 * All rights reserved. See also 'README'
 *
 * Optimize-TODO: put short bands into the band-field without the stride of 3 reals
 * Length-optimze: unify long and short band code where it is possible
 */

#include <stdlib.h>
#include "mpg123.h"
#include "huffman.h"

#include "getbits.h"

static real ispow[8207];
static real aa_ca[8], aa_cs[8];
static real COS1[12][6];
static real win[4][36];
static real win1[4][36];
static real gainpow2[256 + 118 + 4];
real COS9[9];
static real COS6_1, COS6_2;
real tfcos36[9];
static real tfcos12[3];
#define NEW_DCT9
#ifdef NEW_DCT9
static real cos9[3], cos18[3];
#endif

#ifdef USE_SIMD
# define DCT36 (fr->dct36)
#else
# define DCT36 mpg123_dct36
#endif

struct bandInfoStruct
{
	int longIdx[23];
	int longDiff[22];
	int shortIdx[14];
	int shortDiff[13];
};

int longLimit[9][23];
int shortLimit[9][14];

/* Used by the getbits macros */
static unsigned long rval;
static unsigned char rval_uc;

struct bandInfoStruct bandInfo[9] =
{
/* MPEG 1.0 */
 { {0,4,8,12,16,20,24,30,36,44,52,62,74, 90,110,134,162,196,238,288,342,418,576},
   {4,4,4,4,4,4,6,6,8, 8,10,12,16,20,24,28,34,42,50,54, 76,158},
   {0,4*3,8*3,12*3,16*3,22*3,30*3,40*3,52*3,66*3, 84*3,106*3,136*3,192*3},
   {4,4,4,4,6,8,10,12,14,18,22,30,56} } ,

 { {0,4,8,12,16,20,24,30,36,42,50,60,72, 88,106,128,156,190,230,276,330,384,576},
   {4,4,4,4,4,4,6,6,6, 8,10,12,16,18,22,28,34,40,46,54, 54,192},
   {0,4*3,8*3,12*3,16*3,22*3,28*3,38*3,50*3,64*3, 80*3,100*3,126*3,192*3},
   {4,4,4,4,6,6,10,12,14,16,20,26,66} } ,

 { {0,4,8,12,16,20,24,30,36,44,54,66,82,102,126,156,194,240,296,364,448,550,576} ,
   {4,4,4,4,4,4,6,6,8,10,12,16,20,24,30,38,46,56,68,84,102, 26} ,
   {0,4*3,8*3,12*3,16*3,22*3,30*3,42*3,58*3,78*3,104*3,138*3,180*3,192*3} ,
   {4,4,4,4,6,8,12,16,20,26,34,42,12} }  ,

/* MPEG 2.0 */
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576},
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54 } ,
   {0,4*3,8*3,12*3,18*3,24*3,32*3,42*3,56*3,74*3,100*3,132*3,174*3,192*3} ,
   {4,4,4,6,6,8,10,14,18,26,32,42,18 } } ,
/*
 { {0,6,12,18,24,30,36,44,54,66,80,96,114,136,162,194,232,278,330,394,464,540,576},
   {6,6,6,6,6,6,8,10,12,14,16,18,22,26,32,38,46,52,64,70,76,36 } ,
*/
/* changed 19th value fropm 330 to 332 */
 { {0,6,12,18,24,30,36,44,54,66,80,96,114,136,162,194,232,278,332,394,464,540,576},
   {6,6,6,6,6,6,8,10,12,14,16,18,22,26,32,38,46,54,62,70,76,36 } ,
   {0,4*3,8*3,12*3,18*3,26*3,36*3,48*3,62*3,80*3,104*3,136*3,180*3,192*3} ,
   {4,4,4,6,8,10,12,14,18,24,32,44,12 } } ,

 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576},
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54 },
   {0,4*3,8*3,12*3,18*3,26*3,36*3,48*3,62*3,80*3,104*3,134*3,174*3,192*3},
   {4,4,4,6,8,10,12,14,18,24,30,40,18 } } ,
/* MPEG 2.5 */
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576} ,
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54},
   {0,12,24,36,54,78,108,144,186,240,312,402,522,576},
   {4,4,4,6,8,10,12,14,18,24,30,40,18} },
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576} ,
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54},
   {0,12,24,36,54,78,108,144,186,240,312,402,522,576},
   {4,4,4,6,8,10,12,14,18,24,30,40,18} },
 { {0,12,24,36,48,60,72,88,108,132,160,192,232,280,336,400,476,566,568,570,572,574,576},
   {12,12,12,12,12,12,16,20,24,28,32,40,48,56,64,76,90,2,2,2,2,2},
   {0, 24, 48, 72,108,156,216,288,372,480,486,492,498,576},
   {8,8,8,12,16,20,24,28,36,2,2,2,26} } ,
};

static int mapbuf0[9][152];
static int mapbuf1[9][156];
static int mapbuf2[9][44];
static int *map[9][3];
static int *mapend[9][3];

static unsigned int n_slen2[512];	/* MPEG 2.0 slen for 'normal' mode */
static unsigned int i_slen2[256];	/* MPEG 2.0 slen for intensity stereo */

static real tan1_1[16], tan2_1[16], tan1_2[16], tan2_2[16];
static real pow1_1[2][16], pow2_1[2][16], pow1_2[2][16], pow2_2[2][16];

/* 
 * init tables for layer-3 
 */
void mpg123_init_layer3(int down_sample_sblimit)
{
	int i, j, k, l;

	for (i = -256; i < 118 + 4; i++)
		gainpow2[i + 256] = pow((double) 2.0, -0.25 * (double) (i + 210));
	for (i = 0; i < 8207; i++)
		ispow[i] = pow((double) i, (double) 4.0 / 3.0);

	for (i = 0; i < 8; i++)
	{
		static double Ci[8] =
		{-0.6, -0.535, -0.33, -0.185, -0.095, -0.041, -0.0142, -0.0037};
		double sq = sqrt(1.0 + Ci[i] * Ci[i]);

		aa_cs[i] = 1.0 / sq;
		aa_ca[i] = Ci[i] / sq;
	}

	for (i = 0; i < 18; i++)
	{
		win[0][i] = win[1][i] = 0.5 * sin(M_PI / 72.0 * (double) (2 * (i + 0) + 1)) / cos(M_PI * (double) (2 * (i + 0) + 19) / 72.0);
		win[0][i + 18] = win[3][i + 18] = 0.5 * sin(M_PI / 72.0 * (double) (2 * (i + 18) + 1)) / cos(M_PI * (double) (2 * (i + 18) + 19) / 72.0);
	}
	for (i = 0; i < 6; i++)
	{
		win[1][i + 18] = 0.5 / cos(M_PI * (double) (2 * (i + 18) + 19) / 72.0);
		win[3][i + 12] = 0.5 / cos(M_PI * (double) (2 * (i + 12) + 19) / 72.0);
		win[1][i + 24] = 0.5 * sin(M_PI / 24.0 * (double) (2 * i + 13)) / cos(M_PI * (double) (2 * (i + 24) + 19) / 72.0);
		win[1][i + 30] = win[3][i] = 0.0;
		win[3][i + 6] = 0.5 * sin(M_PI / 24.0 * (double) (2 * i + 1)) / cos(M_PI * (double) (2 * (i + 6) + 19) / 72.0);
	}

	for (i = 0; i < 9; i++)
		COS9[i] = cos(M_PI / 18.0 * (double) i);

	for (i = 0; i < 9; i++)
		tfcos36[i] = 0.5 / cos(M_PI * (double) (i * 2 + 1) / 36.0);
	for (i = 0; i < 3; i++)
		tfcos12[i] = 0.5 / cos(M_PI * (double) (i * 2 + 1) / 12.0);

	COS6_1 = cos(M_PI / 6.0 * (double) 1);
	COS6_2 = cos(M_PI / 6.0 * (double) 2);

#ifdef NEW_DCT9
	cos9[0] = cos(1.0 * M_PI / 9.0);
	cos9[1] = cos(5.0 * M_PI / 9.0);
	cos9[2] = cos(7.0 * M_PI / 9.0);
	cos18[0] = cos(1.0 * M_PI / 18.0);
	cos18[1] = cos(11.0 * M_PI / 18.0);
	cos18[2] = cos(13.0 * M_PI / 18.0);
#endif

	for (i = 0; i < 12; i++)
	{
		win[2][i] = 0.5 * sin(M_PI / 24.0 * (double) (2 * i + 1)) / cos(M_PI * (double) (2 * i + 7) / 24.0);
		for (j = 0; j < 6; j++)
			COS1[i][j] = cos(M_PI / 24.0 * (double) ((2 * i + 7) * (2 * j + 1)));
	}

	for (j = 0; j < 4; j++)
	{
		static int len[4] = { 36, 36, 12, 36 };

		for (i = 0; i < len[j]; i += 2)
			win1[j][i] = +win[j][i];
		for (i = 1; i < len[j]; i += 2)
			win1[j][i] = -win[j][i];
	}

	for (i = 0; i < 16; i++)
	{
		double t = tan((double) i * M_PI / 12.0);

		tan1_1[i] = t / (1.0 + t);
		tan2_1[i] = 1.0 / (1.0 + t);
		tan1_2[i] = M_SQRT2 * t / (1.0 + t);
		tan2_2[i] = M_SQRT2 / (1.0 + t);

		for (j = 0; j < 2; j++)
		{
			double base = pow(2.0, -0.25 * (j + 1.0));
			double p1 = 1.0, p2 = 1.0;

			if (i > 0)
			{
				if (i & 1)
					p1 = pow(base, (i + 1.0) * 0.5);
				else
					p2 = pow(base, i * 0.5);
			}
			pow1_1[j][i] = p1;
			pow2_1[j][i] = p2;
			pow1_2[j][i] = M_SQRT2 * p1;
			pow2_2[j][i] = M_SQRT2 * p2;
		}
	}

	for (j = 0; j < 9; j++)
	{
		struct bandInfoStruct *bi = &bandInfo[j];
		int *mp;
		int cb, lwin;
		int *bdf;

		mp = map[j][0] = mapbuf0[j];
		bdf = bi->longDiff;
		for (i = 0, cb = 0; cb < 8; cb++, i += *bdf++)
		{
			*mp++ = (*bdf) >> 1;
			*mp++ = i;
			*mp++ = 3;
			*mp++ = cb;
		}
		bdf = bi->shortDiff + 3;
		for (cb = 3; cb < 13; cb++)
		{
			int l = (*bdf++) >> 1;

			for (lwin = 0; lwin < 3; lwin++)
			{
				*mp++ = l;
				*mp++ = i + lwin;
				*mp++ = lwin;
				*mp++ = cb;
			}
			i += 6 * l;
		}
		mapend[j][0] = mp;

		mp = map[j][1] = mapbuf1[j];
		bdf = bi->shortDiff + 0;
		for (i = 0, cb = 0; cb < 13; cb++)
		{
			int l = (*bdf++) >> 1;

			for (lwin = 0; lwin < 3; lwin++)
			{
				*mp++ = l;
				*mp++ = i + lwin;
				*mp++ = lwin;
				*mp++ = cb;
			}
			i += 6 * l;
		}
		mapend[j][1] = mp;

		mp = map[j][2] = mapbuf2[j];
		bdf = bi->longDiff;
		for (cb = 0; cb < 22; cb++)
		{
			*mp++ = (*bdf++) >> 1;
			*mp++ = cb;
		}
		mapend[j][2] = mp;

	}

	for (j = 0; j < 9; j++)
	{
		for (i = 0; i < 23; i++)
		{
			longLimit[j][i] = (bandInfo[j].longIdx[i] - 1 + 8) / 18 + 1;
			if (longLimit[j][i] > (down_sample_sblimit))
				longLimit[j][i] = down_sample_sblimit;
		}
		for (i = 0; i < 14; i++)
		{
			shortLimit[j][i] = (bandInfo[j].shortIdx[i] - 1) / 18 + 1;
			if (shortLimit[j][i] > (down_sample_sblimit))
				shortLimit[j][i] = down_sample_sblimit;
		}
	}

	for (i = 0; i < 5; i++)
	{
		for (j = 0; j < 6; j++)
		{
			for (k = 0; k < 6; k++)
			{
				int n = k + j * 6 + i * 36;

				i_slen2[n] = i | (j << 3) | (k << 6) | (3 << 12);
			}
		}
	}
	for (i = 0; i < 4; i++)
	{
		for (j = 0; j < 4; j++)
		{
			for (k = 0; k < 4; k++)
			{
				int n = k + j * 4 + i * 16;

				i_slen2[n + 180] = i | (j << 3) | (k << 6) | (4 << 12);
			}
		}
	}
	for (i = 0; i < 4; i++)
	{
		for (j = 0; j < 3; j++)
		{
			int n = j + i * 3;

			i_slen2[n + 244] = i | (j << 3) | (5 << 12);
			n_slen2[n + 500] = i | (j << 3) | (2 << 12) | (1 << 15);
		}
	}

	for (i = 0; i < 5; i++)
	{
		for (j = 0; j < 5; j++)
		{
			for (k = 0; k < 4; k++)
			{
				for (l = 0; l < 4; l++)
				{
					int n = l + k * 4 + j * 16 + i * 80;

					n_slen2[n] = i | (j << 3) | (k << 6) | (l << 9) | (0 << 12);
				}
			}
		}
	}
	for (i = 0; i < 5; i++)
	{
		for (j = 0; j < 5; j++)
		{
			for (k = 0; k < 4; k++)
			{
				int n = k + j * 4 + i * 20;

				n_slen2[n + 400] = i | (j << 3) | (k << 6) | (1 << 12);
			}
		}
	}
}

/*
 * read additional side information (for MPEG 1 and MPEG 2)
 */
static int III_get_side_info(struct III_sideinfo *si, int stereo,
			      int ms_stereo, long sfreq, int single, int lsf)
{
	int ch, gr;
	int powdiff = (single == 3) ? 4 : 0;

	static const int tabs[2][5] = { {2, 9, 5, 3, 4}, {1, 8, 1, 2, 9} };
	const int *tab = tabs[lsf];

	si->main_data_begin = mpg123_getbits(tab[1]);
	if (stereo == 1)
		si->private_bits = mpg123_getbits_fast(tab[2]);
	else
		si->private_bits = mpg123_getbits_fast(tab[3]);

	if (!lsf)
	{
		for (ch = 0; ch < stereo; ch++)
		{
			si->ch[ch].gr[0].scfsi = -1;
			si->ch[ch].gr[1].scfsi = mpg123_getbits_fast(4);
		}
	}

	for (gr = 0; gr < tab[0]; gr++)
	{
		for (ch = 0; ch < stereo; ch++)
		{
			register struct gr_info_s *gr_info = &(si->ch[ch].gr[gr]);

			gr_info->part2_3_length = mpg123_getbits(12);
			gr_info->big_values = mpg123_getbits(9);
			if (gr_info->big_values > 288)
			{
				/*  fprintf(stderr, "big_values too large!\n"); */
				/*  gr_info->big_values = 288; */
				return 0;
			}
			gr_info->pow2gain = gainpow2 + 256 - mpg123_getbits_fast(8) + powdiff;
			if (ms_stereo)
				gr_info->pow2gain += 2;
			gr_info->scalefac_compress = mpg123_getbits(tab[4]);

			if (mpg123_get1bit())
			{	/* window switch flag  */
				int i;

				gr_info->block_type = mpg123_getbits_fast(2);
				gr_info->mixed_block_flag = mpg123_get1bit();
				gr_info->table_select[0] = mpg123_getbits_fast(5);
				gr_info->table_select[1] = mpg123_getbits_fast(5);
				/*
				 * table_select[2] not needed, because
				 * there is no region2, but to satisfy
				 * some verifications tools we set it
				 * either.
				 */
				gr_info->table_select[2] = 0;
				for (i = 0; i < 3; i++)
					gr_info->full_gain[i] = gr_info->pow2gain + (mpg123_getbits_fast(3) << 3);

				if (gr_info->block_type == 0)
				{
					/*  fprintf(stderr,	"Blocktype == 0 and window-switching == 1 not allowed.\n"); */
					/*  exit(1); */
					return 0;
				}

				/* region_count/start parameters are implicit in this case. */
				if (!lsf || gr_info->block_type == 2)
					gr_info->region1start = 36 >> 1;
				else
				{
					/* check this again for 2.5 and sfreq=8 */
					if (sfreq == 8)
						gr_info->region1start =	108 >> 1;
					else
						gr_info->region1start =	54 >> 1;
				}
				gr_info->region2start = 576 >> 1;
			}
			else
			{
				int i, r0c, r1c;

				for (i = 0; i < 3; i++)
					gr_info->table_select[i] = mpg123_getbits_fast(5);
				r0c = mpg123_getbits_fast(4);
				r1c = mpg123_getbits_fast(3);
				gr_info->region1start = bandInfo[sfreq].longIdx[r0c + 1] >> 1;
				if (r0c + r1c + 2 > 22)
					gr_info->region2start = 576 >> 1;
				else
					gr_info->region2start = bandInfo[sfreq].longIdx[r0c + 1 + r1c + 1] >> 1;
				gr_info->block_type = 0;
				gr_info->mixed_block_flag = 0;
			}
			if (!lsf)
				gr_info->preflag = mpg123_get1bit();
			gr_info->scalefac_scale = mpg123_get1bit();
			gr_info->count1table_select = mpg123_get1bit();
		}
	}
	return 1;
}


/*
 * read scalefactors
 */
static int III_get_scale_factors_1(int *scf, struct gr_info_s *gr_info)
{
	static const unsigned char slen[2][16] = {
		{0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4},
		{0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3}
	};
	int numbits;
	int num0 = slen[0][gr_info->scalefac_compress];
	int num1 = slen[1][gr_info->scalefac_compress];

	if (gr_info->block_type == 2)
	{
		int i = 18;

		numbits = (num0 + num1) * 18;

		if (gr_info->mixed_block_flag)
		{
			for (i = 8; i; i--)
				*scf++ = mpg123_getbits_fast(num0);
			i = 9;
			numbits -= num0;	/* num0 * 17 + num1 * 18 */
		}

		for (; i; i--)
			*scf++ = mpg123_getbits_fast(num0);
		for (i = 18; i; i--)
			*scf++ = mpg123_getbits_fast(num1);
		*scf++ = 0;
		*scf++ = 0;
		*scf++ = 0;	/* short[13][0..2] = 0 */
	}
	else
	{
		int i;
		int scfsi = gr_info->scfsi;

		if (scfsi < 0)
		{		/* scfsi < 0 => granule == 0 */
			for (i = 11; i; i--)
				*scf++ = mpg123_getbits_fast(num0);
			for (i = 10; i; i--)
				*scf++ = mpg123_getbits_fast(num1);
			numbits = (num0 + num1) * 10 + num0;
			*scf++ = 0;
		}
		else
		{
			numbits = 0;
			if (!(scfsi & 0x8))
			{
				for (i = 0; i < 6; i++)
					*scf++ = mpg123_getbits_fast(num0);
				numbits += num0 * 6;
			}
			else
			{
				scf += 6;
			}

			if (!(scfsi & 0x4))
			{
				for (i = 0; i < 5; i++)
					*scf++ = mpg123_getbits_fast(num0);
				numbits += num0 * 5;
			}
			else
			{
				scf += 5;
			}

			if (!(scfsi & 0x2))
			{
				for (i = 0; i < 5; i++)
					*scf++ = mpg123_getbits_fast(num1);
				numbits += num1 * 5;
			}
			else
			{
				scf += 5;
			}

			if (!(scfsi & 0x1))
			{
				for (i = 0; i < 5; i++)
					*scf++ = mpg123_getbits_fast(num1);
				numbits += num1 * 5;
			}
			else
			{
				scf += 5;
			}
			*scf++ = 0;	/* no l[21] in original sources */
		}
	}
	return numbits;
}

static int III_get_scale_factors_2(int *scf, struct gr_info_s *gr_info, int i_stereo)
{
	unsigned char *pnt;
	int i, j, n = 0, numbits = 0;
	unsigned int slen;

	static unsigned char stab[3][6][4] =
	{
		{{6, 5, 5, 5}, {6, 5, 7, 3}, {11, 10, 0, 0},
		 {7, 7, 7, 0}, {6, 6, 6, 3}, {8, 8, 5, 0}},
		{{9, 9, 9, 9}, {9, 9, 12, 6}, {18, 18, 0, 0},
		 {12, 12, 12, 0}, {12, 9, 9, 6}, {15, 12, 9, 0}},
		{{6, 9, 9, 9}, {6, 9, 12, 6}, {15, 18, 0, 0},
		 {6, 15, 12, 0}, {6, 12, 9, 6}, {6, 18, 9, 0}}
	};

	if (i_stereo)		/* i_stereo AND second channel -> mpg123_do_layer3() checks this */
		slen = i_slen2[gr_info->scalefac_compress >> 1];
	else
		slen = n_slen2[gr_info->scalefac_compress];

	gr_info->preflag = (slen >> 15) & 0x1;

	n = 0;
	if (gr_info->block_type == 2)
	{
		n++;
		if (gr_info->mixed_block_flag)
			n++;
	}

	pnt = stab[n][(slen >> 12) & 0x7];

	for (i = 0; i < 4; i++)
	{
		int num = slen & 0x7;

		slen >>= 3;
		if (num)
		{
			for (j = 0; j < (int) (pnt[i]); j++)
				*scf++ = mpg123_getbits_fast(num);
			numbits += pnt[i] * num;
		}
		else
		{
			for (j = 0; j < (int) (pnt[i]); j++)
				*scf++ = 0;
		}
	}

	n = (n << 1) + 1;
	for (i = 0; i < n; i++)
		*scf++ = 0;

	return numbits;
}

static int pretab1[22] =
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0};
static int pretab2[22] =
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/*
 * Dequantize samples (includes huffman decoding)
 */
/* 24 is enough because tab13 has max. a 19 bit huffvector */
#define BITSHIFT ((sizeof (long) - 1) * 8)

#define REFRESH_MASK()							\
while(num < BITSHIFT) {							\
	mask |= ((unsigned long)mpg123_getbyte()) << (BITSHIFT - num);	\
	num += 8;							\
	part2remain -= 8;						\
}

static int III_dequantize_sample(real xr[SBLIMIT][SSLIMIT], int *scf,
			struct gr_info_s *gr_info, int sfreq, int part2bits)
{
	int shift = 1 + gr_info->scalefac_scale;
	real *xrpnt = (real *) xr;
	int l[3], l3;
	int part2remain = gr_info->part2_3_length - part2bits;