/* * MPEG Audio decoder * Copyright (c) 2001, 2002 Fabrice Bellard. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * @file mpegaudiodec.c * MPEG Audio decoder. */ //#define DEBUG #include "avcodec.h" #include "mpegaudio.h" /* * TODO: * - in low precision mode, use more 16 bit multiplies in synth filter * - test lsf / mpeg25 extensively. */ /* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg audio decoder */ #ifdef CONFIG_MPEGAUDIO_HP #define USE_HIGHPRECISION #endif #ifdef USE_HIGHPRECISION #define FRAC_BITS 23 /* fractional bits for sb_samples and dct */ #define WFRAC_BITS 16 /* fractional bits for window */ #else #define FRAC_BITS 15 /* fractional bits for sb_samples and dct */ #define WFRAC_BITS 14 /* fractional bits for window */ #endif #define FRAC_ONE (1 << FRAC_BITS) #define MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS) #define MUL64(a,b) ((int64_t)(a) * (int64_t)(b)) #define FIX(a) ((int)((a) * FRAC_ONE)) /* WARNING: only correct for posititive numbers */ #define FIXR(a) ((int)((a) * FRAC_ONE + 0.5)) #define FRAC_RND(a) (((a) + (FRAC_ONE/2)) >> FRAC_BITS) #if FRAC_BITS <= 15 typedef int16_t MPA_INT; #else typedef int32_t MPA_INT; #endif /****************/ #define HEADER_SIZE 4 #define BACKSTEP_SIZE 512 typedef struct MPADecodeContext { uint8_t inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE]; /* input buffer */ int inbuf_index; uint8_t *inbuf_ptr, *inbuf; int frame_size; int free_format_frame_size; /* frame size in case of free format (zero if currently unknown) */ /* next header (used in free format parsing) */ uint32_t free_format_next_header; int error_protection; int layer; int sample_rate; int sample_rate_index; /* between 0 and 8 */ int bit_rate; int old_frame_size; GetBitContext gb; int nb_channels; int mode; int mode_ext; int lsf; MPA_INT synth_buf[MPA_MAX_CHANNELS][512 * 2] __attribute__((aligned(16))); int synth_buf_offset[MPA_MAX_CHANNELS]; int32_t sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT] __attribute__((aligned(16))); int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */ #ifdef DEBUG int frame_count; #endif } MPADecodeContext; /* layer 3 "granule" */ typedef struct GranuleDef { uint8_t scfsi; int part2_3_length; int big_values; int global_gain; int scalefac_compress; uint8_t block_type; uint8_t switch_point; int table_select[3]; int subblock_gain[3]; uint8_t scalefac_scale; uint8_t count1table_select; int region_size[3]; /* number of huffman codes in each region */ int preflag; int short_start, long_end; /* long/short band indexes */ uint8_t scale_factors[40]; int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */ } GranuleDef; #define MODE_EXT_MS_STEREO 2 #define MODE_EXT_I_STEREO 1 /* layer 3 huffman tables */ typedef struct HuffTable { int xsize; const uint8_t *bits; const uint16_t *codes; } HuffTable; #include "mpegaudiodectab.h" /* vlc structure for decoding layer 3 huffman tables */ static VLC huff_vlc[16]; static uint8_t *huff_code_table[16]; static VLC huff_quad_vlc[2]; /* computed from band_size_long */ static uint16_t band_index_long[9][23]; /* XXX: free when all decoders are closed */ #define TABLE_4_3_SIZE (8191 + 16) static int8_t *table_4_3_exp; #if FRAC_BITS <= 15 static uint16_t *table_4_3_value; #else static uint32_t *table_4_3_value; #endif /* intensity stereo coef table */ static int32_t is_table[2][16]; static int32_t is_table_lsf[2][2][16]; static int32_t csa_table[8][2]; static int32_t mdct_win[8][36]; /* lower 2 bits: modulo 3, higher bits: shift */ static uint16_t scale_factor_modshift[64]; /* [i][j]: 2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */ static int32_t scale_factor_mult[15][3]; /* mult table for layer 2 group quantization */ #define SCALE_GEN(v) \ { FIXR(1.0 * (v)), FIXR(0.7937005259 * (v)), FIXR(0.6299605249 * (v)) } static int32_t scale_factor_mult2[3][3] = { SCALE_GEN(4.0 / 3.0), /* 3 steps */ SCALE_GEN(4.0 / 5.0), /* 5 steps */ SCALE_GEN(4.0 / 9.0), /* 9 steps */ }; /* 2^(n/4) */ static uint32_t scale_factor_mult3[4] = { FIXR(1.0), FIXR(1.18920711500272106671), FIXR(1.41421356237309504880), FIXR(1.68179283050742908605), }; static MPA_INT window[512] __attribute__((aligned(16))); /* layer 1 unscaling */ /* n = number of bits of the mantissa minus 1 */ static inline int l1_unscale(int n, int mant, int scale_factor) { int shift, mod; int64_t val; shift = scale_factor_modshift[scale_factor]; mod = shift & 3; shift >>= 2; val = MUL64(mant + (-1 << n) + 1, scale_factor_mult[n-1][mod]); shift += n; /* NOTE: at this point, 1 <= shift >= 21 + 15 */ return (int)((val + (1LL << (shift - 1))) >> shift); } static inline int l2_unscale_group(int steps, int mant, int scale_factor) { int shift, mod, val; shift = scale_factor_modshift[scale_factor]; mod = shift & 3; shift >>= 2; val = (mant - (steps >> 1)) * scale_factor_mult2[steps >> 2][mod]; /* NOTE: at this point, 0 <= shift <= 21 */ if (shift > 0) val = (val + (1 << (shift - 1))) >> shift; return val; } /* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */ static inline int l3_unscale(int value, int exponent) { #if FRAC_BITS <= 15 unsigned int m; #else uint64_t m; #endif int e; e = table_4_3_exp[value]; e += (exponent >> 2); e = FRAC_BITS - e; #if FRAC_BITS <= 15 if (e > 31) e = 31; #endif m = table_4_3_value[value]; #if FRAC_BITS <= 15 m = (m * scale_factor_mult3[exponent & 3]); m = (m + (1 << (e-1))) >> e; return m; #else m = MUL64(m, scale_factor_mult3[exponent & 3]); m = (m + (uint64_t_C(1) << (e-1))) >> e; return m; #endif } /* all integer n^(4/3) computation code */ #define DEV_ORDER 13 #define POW_FRAC_BITS 24 #define POW_FRAC_ONE (1 << POW_FRAC_BITS) #define POW_FIX(a) ((int)((a) * POW_FRAC_ONE)) #define POW_MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> POW_FRAC_BITS) static int dev_4_3_coefs[DEV_ORDER]; static int pow_mult3[3] = { POW_FIX(1.0), POW_FIX(1.25992104989487316476), POW_FIX(1.58740105196819947474), }; static void int_pow_init(void) { int i, a; a = POW_FIX(1.0); for(i=0;i<DEV_ORDER;i++) { a = POW_MULL(a, POW_FIX(4.0 / 3.0) - i * POW_FIX(1.0)) / (i + 1); dev_4_3_coefs[i] = a; } } /* return the mantissa and the binary exponent */ static int int_pow(int i, int *exp_ptr) { int e, er, eq, j; int a, a1; /* renormalize */ a = i; e = POW_FRAC_BITS; while (a < (1 << (POW_FRAC_BITS - 1))) { a = a << 1; e--; } a -= (1 << POW_FRAC_BITS); a1 = 0; for(j = DEV_ORDER - 1; j >= 0; j--) a1 = POW_MULL(a, dev_4_3_coefs[j] + a1); a = (1 << POW_FRAC_BITS) + a1; /* exponent compute (exact) */ e = e * 4; er = e % 3; eq = e / 3; a = POW_MULL(a, pow_mult3[er]); while (a >= 2 * POW_FRAC_ONE) { a = a >> 1; eq++; } /* convert to float */ while (a < POW_FRAC_ONE) { a = a << 1; eq--; } /* now POW_FRAC_ONE <= a < 2 * POW_FRAC_ONE */ #if POW_FRAC_BITS > FRAC_BITS a = (a + (1 << (POW_FRAC_BITS - FRAC_BITS - 1))) >> (POW_FRAC_BITS - FRAC_BITS); /* correct overflow */ if (a >= 2 * (1 << FRAC_BITS)) { a = a >> 1; eq++; } #endif *exp_ptr = eq; return a; } static int decode_init(AVCodecContext * avctx) { MPADecodeContext *s = avctx->priv_data; static int init=0; int i, j, k; if(!init) { /* scale factors table for layer 1/2 */ for(i=0;i<64;i++) { int shift, mod; /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */ shift = (i / 3); mod = i % 3; scale_factor_modshift[i] = mod | (shift << 2); } /* scale factor multiply for layer 1 */ for(i=0;i<15;i++) { int n, norm; n = i + 2; norm = ((int64_t_C(1) << n) * FRAC_ONE) / ((1 << n) - 1); scale_factor_mult[i][0] = MULL(FIXR(1.0 * 2.0), norm); scale_factor_mult[i][1] = MULL(FIXR(0.7937005259 * 2.0), norm); scale_factor_mult[i][2] = MULL(FIXR(0.6299605249 * 2.0), norm); dprintf("%d: norm=%x s=%x %x %x\n", i, norm, scale_factor_mult[i][0], scale_factor_mult[i][1], scale_factor_mult[i][2]); } /* window */ /* max = 18760, max sum over all 16 coefs : 44736 */ for(i=0;i<257;i++) { int v; v = mpa_enwindow[i]; #if WFRAC_BITS < 16 v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS); #endif window[i] = v; if ((i & 63) != 0) v = -v; if (i != 0) window[512 - i] = v; } /* huffman decode tables */ huff_code_table[0] = NULL; for(i=1;i<16;i++) { const HuffTable *h = &mpa_huff_tables[i]; int xsize, x, y; unsigned int n; uint8_t *code_table; xsize = h->xsize; n = xsize * xsize; /* XXX: fail test */ init_vlc(&huff_vlc[i], 8, n, h->bits, 1, 1, h->codes, 2, 2); code_table = av_mallocz(n); j = 0; for(x=0;x<xsize;x++) { for(y=0;y<xsize;y++) code_table[j++] = (x << 4) | y; } huff_code_table[i] = code_table; } for(i=0;i<2;i++) { init_vlc(&huff_quad_vlc[i], i == 0 ? 7 : 4, 16, mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1); } for(i=0;i<9;i++) { k = 0; for(j=0;j<22;j++) { band_index_long[i][j] = k; k += band_size_long[i][j]; } band_index_long[i][22] = k; } /* compute n ^ (4/3) and store it in mantissa/exp format */ if (!av_mallocz_static(&table_4_3_exp, TABLE_4_3_SIZE * sizeof(table_4_3_exp[0]))) return -1; if (!av_mallocz_static(&table_4_3_value, TABLE_4_3_SIZE * sizeof(table_4_3_value[0]))) return -1; int_pow_init(); for(i=1;i<TABLE_4_3_SIZE;i++) { int e, m; m = int_pow(i, &e); #if 0 /* test code */ { double f, fm; int e1, m1; f = pow((double)i, 4.0 / 3.0); fm = frexp(f, &e1); m1 = FIXR(2 * fm); #if FRAC_BITS <= 15 if ((unsigned short)m1 != m1) { m1 = m1 >> 1; e1++; } #endif e1--; if (m != m1 || e != e1) { printf("%4d: m=%x m1=%x e=%d e1=%d\n", i, m, m1, e, e1); } } #endif /* normalized to FRAC_BITS */ table_4_3_value[i] = m; table_4_3_exp[i] = e; } for(i=0;i<7;i++) { float f; int v; if (i != 6) { f = tan((double)i * M_PI / 12.0); v = FIXR(f / (1.0 + f)); } else { v = FIXR(1.0); } is_table[0][i] = v; is_table[1][6 - i] = v; } /* invalid values */ for(i=7;i<16;i++) is_table[0][i] = is_table[1][i] = 0.0; for(i=0;i<16;i++) { double f; int e, k; for(j=0;j<2;j++) { e = -(j + 1) * ((i + 1) >> 1); f = pow(2.0, e / 4.0); k = i & 1; is_table_lsf[j][k ^ 1][i] = FIXR(f); is_table_lsf[j][k][i] = FIXR(1.0); dprintf("is_table_lsf %d %d: %x %x\n", i, j, is_table_lsf[j][0][i], is_table_lsf[j][1][i]); } } for(i=0;i<8;i++) { float ci, cs, ca; ci = ci_table[i]; cs = 1.0 / sqrt(1.0 + ci * ci); ca = cs * ci; csa_table[i][0] = FIX(cs); csa_table[i][1] = FIX(ca); } /* compute mdct windows */ for(i=0;i<36;i++) { int v; v = FIXR(sin(M_PI * (i + 0.5) / 36.0)); mdct_win[0][i] = v; mdct_win[1][i] = v; mdct_win[3][i] = v; } for(i=0;i<6;i++) { mdct_win[1][18 + i] = FIXR(1.0); mdct_win[1][24 + i] = FIXR(sin(M_PI * ((i + 6) + 0.5) / 12.0)); mdct_win[1][30 + i] = FIXR(0.0); mdct_win[3][i] = FIXR(0.0); mdct_win[3][6 + i] = FIXR(sin(M_PI * (i + 0.5) / 12.0)); mdct_win[3][12 + i] = FIXR(1.0); } for(i=0;i<12;i++) mdct_win[2][i] = FIXR(sin(M_PI * (i + 0.5) / 12.0)); /* NOTE: we do frequency inversion adter the MDCT by changing the sign of the right window coefs */ for(j=0;j<4;j++) { for(i=0;i<36;i+=2) { mdct_win[j + 4][i] = mdct_win[j][i]; mdct_win[j + 4][i + 1] = -mdct_win[j][i + 1]; } } #if defined(DEBUG) for(j=0;j<8;j++) { printf("win%d=\n", j); for(i=0;i<36;i++) printf("%f, ", (double)mdct_win[j][i] / FRAC_ONE); printf("\n"); } #endif init = 1; } s->inbuf_index = 0; s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE]; s->inbuf_ptr = s->inbuf; #ifdef DEBUG s->frame_count = 0; #endif return 0; } /* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */ /* cos(i*pi/64) */ #define COS0_0 FIXR(0.50060299823519630134) #define COS0_1 FIXR(0.50547095989754365998) #define COS0_2 FIXR(0.51544730992262454697) #define COS0_3 FIXR(0.53104259108978417447) #define COS0_4 FIXR(0.55310389603444452782) #define COS0_5 FIXR(0.58293496820613387367) #define COS0_6 FIXR(0.62250412303566481615) #define COS0_7 FIXR(0.67480834145500574602) #define COS0_8 FIXR(0.74453627100229844977) #define COS0_9 FIXR(0.83934964541552703873) #define COS0_10 FIXR(0.97256823786196069369) #define COS0_11 FIXR(1.16943993343288495515) #define COS0_12 FIXR(1.48416461631416627724) #define COS0_13 FIXR(2.05778100995341155085) #define COS0_14 FIXR(3.40760841846871878570) #define COS0_15 FIXR(10.19000812354805681150) #define COS1_0 FIXR(0.50241928618815570551) #define COS1_1 FIXR(0.52249861493968888062) #define COS1_2 FIXR(0.56694403481635770368) #define COS1_3 FIXR(0.64682178335999012954) #define COS1_4 FIXR(0.78815462345125022473) #define COS1_5 FIXR(1.06067768599034747134) #define COS1_6 FIXR(1.72244709823833392782) #define COS1_7 FIXR(5.10114861868916385802) #define COS2_0 FIXR(0.50979557910415916894) #define COS2_1 FIXR(0.60134488693504528054) #define COS2_2 FIXR(0.89997622313641570463) #define COS2_3 FIXR(2.56291544774150617881) #define COS3_0 FIXR(0.54119610014619698439) #define COS3_1 FIXR(1.30656296487637652785) #define COS4_0 FIXR(0.70710678118654752439) /* butterfly operator */ #define BF(a, b, c)\ {\ tmp0 = tab[a] + tab[b];\ tmp1 = tab[a] - tab[b];\ tab[a] = tmp0;\ tab[b] = MULL(tmp1, c);\ } #define BF1(a, b, c, d)\ {\ BF(a, b, COS4_0);\ BF(c, d, -COS4_0);\ tab[c] += tab[d];\ } #define BF2(a, b, c, d)\ {\ BF(a, b, COS4_0);\ BF(c, d, -COS4_0);\ tab[c] += tab[d];\ tab[a] += tab[c];\ tab[c] += tab[b];\ tab[b] += tab[d];\ } #define ADD(a, b) tab[a] += tab[b] /* DCT32 without 1/sqrt(2) coef zero scaling. */ static void dct32(int32_t *out, int32_t *tab) { int tmp0, tmp1; /* pass 1 */ BF(0, 31, COS0_0); BF(1, 30, COS0_1); BF(2, 29, COS0_2); BF(3, 28, COS0_3); BF(4, 27, COS0_4); BF(5, 26, COS0_5); BF(6, 25, COS0_6); BF(7, 24, COS0_7); BF(8, 23, COS0_8); BF(9, 22, COS0_9); BF(10, 21, COS0_10); BF(11, 20, COS0_11); BF(12, 19, COS0_12); BF(13, 18, COS0_13); BF(14, 17, COS0_14); BF(15, 16, COS0_15); /* pass 2 */ BF(0, 15, COS1_0); BF(1, 14, COS1_1); BF(2, 13, COS1_2); BF(3, 12, COS1_3); BF(4, 11, COS1_4); BF(5, 10, COS1_5); BF(6, 9, COS1_6); BF(7, 8, COS1_7); BF(16, 31, -COS1_0); BF(17, 30, -COS1_1); BF(18, 29, -COS1_2); BF(19, 28, -COS1_3); BF(20, 27, -COS1_4); BF(21, 26, -COS1_5); BF(22, 25, -COS1_6); BF(23, 24, -COS1_7); /* pass 3 */ BF(0, 7, COS2_0); BF(1, 6, COS2_1); BF(2, 5, COS2_2); BF(3, 4, COS2_3); BF(8, 15, -COS2_0); BF(9, 14, -COS2_1); BF(10, 13, -COS2_2); BF(11, 12, -COS2_3); BF(16, 23, COS2_0); BF(17, 22, COS2_1); BF(18, 21, COS2_2); BF(19, 20, COS2_3); BF(24, 31, -COS2_0); BF(25, 30, -COS2_1); BF(26, 29, -COS2_2); BF(27, 28, -COS2_3); /* pass 4 */ BF(0, 3, COS3_0); BF(1, 2, COS3_1); BF(4, 7, -COS3_0); BF(5, 6, -COS3_1); BF(8, 11, COS3_0); BF(9, 10, COS3_1); BF(12, 15, -COS3_0); BF(13, 14, -COS3_1); BF(16, 19, COS3_0); BF(17, 18, COS3_1); BF(20, 23, -COS3_0); BF(21, 22, -COS3_1); BF(24, 27, COS3_0); BF(25, 26, COS3_1); BF(28, 31, -COS3_0); BF(29, 30, -COS3_1); /* pass 5 */ BF1(0, 1, 2, 3); BF2(4, 5, 6, 7); BF1(8, 9, 10, 11); BF2(12, 13, 14, 15); BF1(16, 17, 18, 19); BF2(20, 21, 22, 23); BF1(24, 25, 26, 27); BF2(28, 29, 30, 31); /* pass 6 */ ADD( 8, 12); ADD(12, 10); ADD(10, 14); ADD(14, 9); ADD( 9, 13); ADD(13, 11); ADD(11, 15); out[ 0] = tab[0]; out[16] = tab[1]; out[ 8] = tab[2]; out[24] = tab[3]; out[ 4] = tab[4]; out[20] = tab[5]; out[12] = tab[6]; out[28] = tab[7]; out[ 2] = tab[8]; out[18] = tab[9]; out[10] = tab[10]; out[26] = tab[11]; out[ 6] = tab[12]; out[22] = tab[13]; out[14] = tab[14]; out[30] = tab[15]; ADD(24, 28); ADD(28, 26); ADD(26, 30); ADD(30, 25); ADD(25, 29); ADD(29, 27); ADD(27, 31); out[ 1] = tab[16] + tab[24]; out[17] = tab[17] + tab[25]; out[ 9] = tab[18] + tab[26]; out[25] = tab[19] + tab[27]; out[ 5] = tab[20] + tab[28]; out[21] = tab[21] + tab[29]; out[13] = tab[22] + tab[30]; out[29] = tab[23] + tab[31]; out[ 3] = tab[24] + tab[20]; out[19] = tab[25] + tab[21]; out[11] = tab[26] + tab[22]; out[27] = tab[27] + tab[23]; out[ 7] = tab[28] + tab[18]; out[23] = tab[29] + tab[19]; out[15] = tab[30] + tab[17]; out[31] = tab[31]; } #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15) #if FRAC_BITS <= 15 #define OUT_SAMPLE(sum)\ {\ int sum1;\ sum1 = (sum + (1 << (OUT_SHIFT - 1))) >> OUT_SHIFT;\ if (sum1 < -32768)\ sum1 = -32768;\ else if (sum1 > 32767)\ sum1 = 32767;\ *samples = sum1;\ samples += incr;\ } #define SUM8(off, op) \ { \ sum op w[0 * 64 + off] * p[0 * 64];\ sum op w[1 * 64 + off] * p[1 * 64];\ sum op w[2 * 64 + off] * p[2 * 64];\ sum op w[3 * 64 + off] * p[3 * 64];\ sum op w[4 * 64 + off] * p[4 * 64];\ sum op w[5 * 64 + off] * p[5 * 64];\ sum op w[6 * 64 + off] * p[6 * 64];\ sum op w[7 * 64 + off] * p[7 * 64];\ } #else #define OUT_SAMPLE(sum)\ {\ int sum1;\ sum1 = (int)((sum + (int64_t_C(1) << (OUT_SHIFT - 1))) >> OUT_SHIFT);\ if (sum1 < -32768)\ sum1 = -32768;\ else if (sum1 > 32767)\ sum1 = 32767;\ *samples = sum1;\ samples += incr;\ } #define SUM8(off, op) \ { \ sum op MUL64(w[0 * 64 + off], p[0 * 64]);\ sum op MUL64(w[1 * 64 + off], p[1 * 64]);\ sum op MUL64(w[2 * 64 + off], p[2 * 64]);\ sum op MUL64(w[3 * 64 + off], p[3 * 64]);\ sum op MUL64(w[4 * 64 + off], p[4 * 64]);\ sum op MUL64(w[5 * 64 + off], p[5 * 64]);\ sum op MUL64(w[6 * 64 + off], p[6 * 64]);\ sum op MUL64(w[7 * 64 + off], p[7 * 64]);\ } #endif /* 32 sub band synthesis filter. Input: 32 sub band samples, Output: 32 samples. */ /* XXX: optimize by avoiding ring buffer usage */ static void synth_filter(MPADecodeContext *s1, int ch, int16_t *samples, int incr, int32_t sb_samples[SBLIMIT]) { int32_t tmp[32]; register MPA_INT *synth_buf, *p; register MPA_INT *w; int j, offset, v; #if FRAC_BITS <= 15 int sum; #else int64_t sum; #endif dct32(tmp, sb_samples); offset = s1->synth_buf_offset[ch]; synth_buf = s1->synth_buf[ch] + offset; for(j=0;j<32;j++) { v = tmp[j]; #if FRAC_BITS <= 15 /* NOTE: can cause a loss in precision if very high amplitude sound */ if (v > 32767) v = 32767; else if (v < -32768) v = -32768; #endif synth_buf[j] = v; } /* copy to avoid wrap */ memcpy(synth_buf + 512, synth_buf, 32 * sizeof(MPA_INT)); w = window; for(j=0;j<16;j++) { sum = 0; p = synth_buf + 16 + j; /* 0-15 */ SUM8(0, +=); p = synth_buf + 48 - j; /* 32-47 */ SUM8(32, -=); OUT_SAMPLE(sum); w++; } p = synth_buf + 32; /* 48 */ sum = 0; SUM8(32, -=); OUT_SAMPLE(sum); w++; for(j=17;j<32;j++) { sum = 0; p = synth_buf + 48 - j; /* 17-31 */ SUM8(0, -=); p = synth_buf + 16 + j; /* 49-63 */ SUM8(32, -=); OUT_SAMPLE(sum); w++; } offset = (offset - 32) & 511; s1->synth_buf_offset[ch] = offset; } /* cos(pi*i/24) */ #define C1 FIXR(0.99144486137381041114) #define C3 FIXR(0.92387953251128675612) #define C5 FIXR(0.79335334029123516458) #define C7 FIXR(0.60876142900872063941) #define C9 FIXR(0.38268343236508977173) #define C11 FIXR(0.13052619222005159154) /* 12 points IMDCT. We compute it "by hand" by factorizing obvious cases. */ static void imdct12(int *out, int *in) { int tmp; int64_t in1_3, in1_9, in4_3, in4_9; in1_3 = MUL64(in[1], C3); in1_9 = MUL64(in[1], C9); in4_3 = MUL64(in[4], C3); in4_9 = MUL64(in[4], C9); tmp = FRAC_RND(MUL64(in[0], C7) - in1_3 - MUL64(in[2], C11) + MUL64(in[3], C1) - in4_9 - MUL64(in[5], C5)); out[0] = tmp; out[5] = -tmp; tmp = FRAC_RND(MUL64(in[0] - in[3], C9) - in1_3 + MUL64(in[2] + in[5], C3) - in4_9); out[1] = tmp; out[4] = -tmp; tmp = FRAC_RND(MUL64(in[0], C11) - in1_9 + MUL64(in[2], C7) - MUL64(in[3], C5) + in4_3 - MUL64(in[5], C1)); out[2] = tmp; out[3] = -tmp; tmp = FRAC_RND(MUL64(-in[0], C5) + in1_9 + MUL64(in[2], C1) + MUL64(in[3], C11) - in4_3 - MUL64(in[5], C7)); out[6] = tmp; out[11] = tmp; tmp = FRAC_RND(MUL64(-in[0] + in[3], C3) - in1_9 + MUL64(in[2] + in[5], C9) + in4_3); out[7] = tmp; out[10] = tmp; tmp = FRAC_RND(-MUL64(in[0], C1) - in1_3 - MUL64(in[2], C5) - MUL64(in[3], C7) - in4_9 - MUL64(in[5], C11)); out[8] = tmp; out[9] = tmp; } #undef C1 #undef C3 #undef C5 #undef C7 #undef C9 #undef C11 /* cos(pi*i/18) */ #define C1 FIXR(0.98480775301220805936) #define C2 FIXR(0.93969262078590838405) #define C3 FIXR(0.86602540378443864676) #define C4 FIXR(0.76604444311897803520) #define C5 FIXR(0.64278760968653932632) #define C6 FIXR(0.5) #define C7 FIXR(0.34202014332566873304) #define C8 FIXR(0.17364817766693034885) /* 0.5 / cos(pi*(2*i+1)/36) */ static const int icos36[9] = { FIXR(0.50190991877167369479), FIXR(0.51763809020504152469), FIXR(0.55168895948124587824), FIXR(0.61038729438072803416), FIXR(0.70710678118654752439), FIXR(0.87172339781054900991), FIXR(1.18310079157624925896), FIXR(1.93185165257813657349), FIXR(5.73685662283492756461), }; static const int icos72[18] = { /* 0.5 / cos(pi*(2*i+19)/72) */ FIXR(0.74009361646113053152), FIXR(0.82133981585229078570), FIXR(0.93057949835178895673), FIXR(1.08284028510010010928), FIXR(1.30656296487637652785), FIXR(1.66275476171152078719), FIXR(2.31011315767264929558), FIXR(3.83064878777019433457), FIXR(11.46279281302667383546), /* 0.5 / cos(pi*(2*(i + 18) +19)/72) */ FIXR(-0.67817085245462840086), FIXR(-0.63023620700513223342), FIXR(-0.59284452371708034528), FIXR(-0.56369097343317117734), FIXR(-0.54119610014619698439), FIXR(-0.52426456257040533932), FIXR(-0.51213975715725461845), FIXR(-0.50431448029007636036), FIXR(-0.50047634258165998492), }; /* using Lee like decomposition followed by hand coded 9 points DCT */ static void imdct36(int *out, int *in) { int i, j, t0, t1, t2, t3, s0, s1, s2, s3; int tmp[18], *tmp1, *in1; int64_t in3_3, in6_6; for(i=17;i>=1;i--) in[i] += in[i-1]; for(i=17;i>=3;i-=2) in[i] += in[i-2]; for(j=0;j<2;j++) { tmp1 = tmp + j; in1 = in + j; in3_3 = MUL64(in1[2*3], C3); in6_6 = MUL64(in1[2*6], C6); tmp1[0] = FRAC_RND(MUL64(in1[2*1], C1) + in3_3 + MUL64(in1[2*5], C5) + MUL64(in1[2*7], C7)); tmp1[2] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C2) + MUL64(in1[2*4], C4) + in6_6 + MUL64(in1[2*8], C8)); tmp1[4] = FRAC_RND(MUL64(in1[2*1] - in1[2*5] - in1[2*7], C3)); tmp1[6] = FRAC_RND(MUL64(in1[2*2] - in1[2*4] - in1[2*8], C6)) - in1[2*6] + in1[2*0]; tmp1[8] = FRAC_RND(MUL64(in1[2*1], C5) - in3_3 - MUL64(in1[2*5], C7) + MUL64(in1[2*7], C1)); tmp1[10] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C8) - MUL64(in1[2*4], C2) + in6_6 + MUL64(in1[2*8], C4)); tmp1[12] = FRAC_RND(MUL64(in1[2*1], C7) - in3_3 + MUL64(in1[2*5], C1) - MUL64(in1[2*7], C5)); tmp1[14] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C4) + MUL64(in1[2*4], C8) + in6_6 - MUL64(in1[2*8], C2)); tmp1[16] = in1[2*0] - in1[2*2] + in1[2*4] - in1[2*6] + in1[2*8]; } i = 0; for(j=0;j<4;j++) { t0 = tmp[i]; t1 = tmp[i + 2]; s0 = t1 + t0; s2 = t1 - t0; t2 = tmp[i + 1]; t3 = tmp[i + 3]; s1 = MULL(t3 + t2, icos36[j]); s3 = MULL(t3 - t2, icos36[8 - j]); t0 = MULL(s0 + s1, icos72[9 + 8 - j]); t1 = MULL(s0 - s1, icos72[8 - j]); out[18 + 9 + j] = t0; out[18 + 8 - j] = t0; out[9 + j] = -t1; out[8 - j] = t1; t0 = MULL(s2 + s3, icos72[9+j]); t1 = MULL(s2 - s3, icos72[j]); out[18 + 9 + (8 - j)] = t0; out[18 + j] = t0; out[9 + (8 - j)] = -t1; out[j] = t1; i += 4; } s0 = tmp[16]; s1 = MULL(tmp[17], icos36[4]); t0 = MULL(s0 + s1, icos72[9 + 4]); t1 = MULL(s0 - s1, icos72[4]); out[18 + 9 + 4] = t0; out[18 + 8 - 4] = t0; out[9 + 4] = -t1; out[8 - 4] = t1; } /* fast header check for resync */ static int check_header(uint32_t header) { /* header */ if ((header & 0xffe00000) != 0xffe00000) return -1; /* layer check */ if (((header >> 17) & 3) == 0) return -1; /* bit rate */ if (((header >> 12) & 0xf) == 0xf) return -1; /* frequency */ if (((header >> 10) & 3) == 3) return -1; return 0; } /* header + layer + bitrate + freq + lsf/mpeg25 */ #define SAME_HEADER_MASK \ (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19)) /* header decoding. MUST check the header before because no consistency check is done there. Return 1 if free format found and that the frame size must be computed externally */ static int decode_header(MPADecodeContext *s, uint32_t header) { int sample_rate, frame_size, mpeg25, padding; int sample_rate_index, bitrate_index; if (header & (1<<20)) { s->lsf = (header & (1<<19)) ? 0 : 1; mpeg25 = 0; } else { s->lsf = 1; mpeg25 = 1; } s->layer = 4 - ((header >> 17) & 3); /* extract frequency */ sample_rate_index = (header >> 10) & 3; sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25); sample_rate_index += 3 * (s->lsf + mpeg25); s->sample_rate_index = sample_rate_index; s->error_protection = ((header >> 16) & 1) ^ 1; s->sample_rate = sample_rate; bitrate_index = (header >> 12) & 0xf; padding = (header >> 9) & 1; //extension = (header >> 8) & 1; s->mode = (header >> 6) & 3; s->mode_ext = (header >> 4) & 3; //copyright = (header >> 3) & 1; //original = (header >> 2) & 1; //emphasis = header & 3; if (s->mode == MPA_MONO) s->nb_channels = 1; else s->nb_channels = 2; if (bitrate_index != 0) { frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index]; s->bit_rate = frame_size * 1000; switch(s->layer) { case 1: frame_size = (frame_size * 12000) / sample_rate; frame_size = (frame_size + padding) * 4; break; case 2: frame_size = (frame_size * 144000) / sample_rate; frame_size += padding; break; default: case 3: frame_size = (frame_size * 144000) / (sample_rate << s->lsf); frame_size += padding; break; } s->frame_size = frame_size; } else { /* if no frame size computed, signal it */ if (!s->free_format_frame_size) return 1; /* free format: compute bitrate and real frame size from the frame size we extracted by reading the bitstream */ s->frame_size = s->free_format_frame_size; switch(s->layer) { case 1: s->frame_size += padding * 4; s->bit_rate = (s->frame_size * sample_rate) / 48000; break; case 2: s->frame_size += padding; s->bit_rate = (s->frame_size * sample_rate) / 144000; break; default: case 3: s->frame_size += padding; s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000; break; } } #if defined(DEBUG) printf("layer%d, %d Hz, %d kbits/s, ", s->layer, s->sample_rate, s->bit_rate); if (s->nb_channels == 2) { if (s->layer == 3) { if (s->mode_ext & MODE_EXT_MS_STEREO) printf("ms-"); if (s->mode_ext & MODE_EXT_I_STEREO) printf("i-"); } printf("stereo"); } else { printf("mono"); } printf("\n"); #endif return 0; } /* return the number of decoded frames */ static int mp_decode_layer1(MPADecodeContext *s) { int bound, i, v, n, ch, j, mant; uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT]; uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT]; if (s->mode == MPA_JSTEREO) bound = (s->mode_ext + 1) * 4; else bound = SBLIMIT; /* allocation bits */ for(i=0;i<bound;i++) { for(ch=0;ch<s->nb_channels;ch++) { allocation[ch][i] = get_bits(&s->gb, 4); } } for(i=bound;i<SBLIMIT;i++) { allocation[0][i] = get_bits(&s->gb, 4); } /* scale factors */ for(i=0;i<bound;i++) { for(ch=0;ch<s->nb_channels;ch++) { if (allocation[ch][i]) scale_factors[ch][i] = get_bits(&s->gb, 6); } } for(i=bound;i<SBLIMIT;i++) { if (allocation[0][i]) { scale_factors[0][i] = get_bits(&s->gb, 6); scale_factors[1][i] = get_bits(&s->gb, 6); } } /* compute samples */ for(j=0;j<12;j++) { for(i=0;i<bound;i++) { for(ch=0;ch<s->nb_channels;ch++) { n = allocation[ch][i]; if (n) { mant = get_bits(&s->gb, n + 1); v = l1_unscale(n, mant, scale_factors[ch][i]); } else { v = 0; } s->sb_samples[ch][j][i] = v; } } for(i=bound;i<SBLIMIT;i++) { n = allocation[0][i]; if (n) { mant = get_bits(&s->gb, n + 1); v = l1_unscale(n, mant, scale_factors[0][i]); s->sb_samples[0][j][i] = v; v = l1_unscale(n, mant, scale_factors[1][i]); s->sb_samples[1][j][i] = v; } else { s->sb_samples[0][j][i] = 0; s->sb_samples[1][j][i] = 0; } } } return 12; } /* bitrate is in kb/s */ int l2_select_table(int bitrate, int nb_channels, int freq, int lsf) { int ch_bitrate, table; ch_bitrate = bitrate / nb_channels; if (!lsf) { if ((freq == 48000 && ch_bitrate >= 56) || (ch_bitrate >= 56 && ch_bitrate <= 80)) table = 0; else if (freq != 48000 && ch_bitrate >= 96) table = 1; else if (freq != 32000 && ch_bitrate <= 48) table = 2; else table = 3; } else { table = 4; } return table; } static int mp_decode_layer2(MPADecodeContext *s) { int sblimit; /* number of used subbands */ const unsigned char *alloc_table; int table, bit_alloc_bits, i, j, ch, bound, v; unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT]; unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT]; unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf; int scale, qindex, bits, steps, k, l, m, b; /* select decoding table */ table = l2_select_table(s->bit_rate / 1000, s->nb_channels, s->sample_rate, s->lsf); sblimit = sblimit_table[table]; alloc_table = alloc_tables[table]; if (s->mode == MPA_JSTEREO) bound = (s->mode_ext + 1) * 4; else bound = sblimit; dprintf("bound=%d sblimit=%d\n", bound, sblimit); /* parse bit allocation */ j = 0; for(i=0;i<bound;i++) { bit_alloc_bits = alloc_table[j]; for(ch=0;ch<s->nb_channels;ch++) { bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits); } j += 1 << bit_alloc_bits; } for(i=bound;i<sblimit;i++) { bit_alloc_bits = alloc_table[j]; v = get_bits(&s->gb, bit_alloc_bits); bit_alloc[0][i] = v; bit_alloc[1][i] = v; j += 1 << bit_alloc_bits; } #ifdef DEBUG { for(ch=0;ch<s->nb_channels;ch++) { for(i=0;i<sblimit;i++) printf(" %d", bit_alloc[ch][i]); printf("\n"); } } #endif /* scale codes */ for(i=0;i<sblimit;i++) { for(ch=0;ch<s->nb_channels;ch++) { if (bit_alloc[ch][i]) scale_code[ch][i] = get_bits(&s->gb, 2); } } /* scale factors */ for(i=0;i<sblimit;i++) { for(ch=0;ch<s->nb_channels;ch++) { if (bit_alloc[ch][i]) { sf = scale_factors[ch][i]; switch(scale_code[ch][i]) { default: case 0: sf[0] = get_bits(&s->gb, 6); sf[1] = get_bits(&s->gb, 6); sf[2] = get_bits(&s->gb, 6); break; case 2: sf[0] = get_bits(&s->gb, 6); sf[1] = sf[0]; sf[2] = sf[0]; break; case 1: sf[0] = get_bits(&s->gb, 6); sf[2] = get_bits(&s->gb, 6); sf[1] = sf[0]; break; case 3: sf[0] = get_bits(&s->gb, 6); sf[2] = get_bits(&s->gb, 6); sf[1] = sf[2]; break; } } } } #ifdef DEBUG for(ch=0;ch<s->nb_channels;ch++) { for(i=0;i<sblimit;i++) { if (bit_alloc[ch][i]) { sf = scale_factors[ch][i]; printf(" %d %d %d", sf[0], sf[1], sf[2]); } else { printf(" -"); } } printf("\n"); } #endif /* samples */ for(k=0;k<3;k++) { for(l=0;l<12;l+=3) { j = 0; for(i=0;i<bound;i++) { bit_alloc_bits = alloc_table[j]; for(ch=0;ch<s->nb_channels;ch++) { b = bit_alloc[ch][i]; if (b) { scale = scale_factors[ch][i][k]; qindex = alloc_table[j+b]; bits = quant_bits[qindex]; if (bits < 0) { /* 3 values at the same time */ v = get_bits(&s->gb, -bits); steps = quant_steps[qindex]; s->sb_samples[ch][k * 12 + l + 0][i] = l2_unscale_group(steps, v % steps, scale); v = v / steps; s->sb_samples[ch][k * 12 + l + 1][i] = l2_unscale_group(steps, v % steps, scale); v = v / steps; s->sb_samples[ch][k * 12 + l + 2][i] = l2_unscale_group(steps, v, scale); } else { for(m=0;m<3;m++) { v = get_bits(&s->gb, bits); v = l1_unscale(bits - 1, v, scale); s->sb_samples[ch][k * 12 + l + m][i] = v; } } } else { s->sb_samples[ch][k * 12 + l + 0][i] = 0; s->sb_samples[ch][k * 12 + l + 1][i] = 0; s->sb_samples[ch][k * 12 + l + 2][i] = 0; } } /* next subband in alloc table */ j += 1 << bit_alloc_bits; } /* XXX: find a way to avoid this duplication of code */ for(i=bound;i<sblimit;i++) { bit_alloc_bits = alloc_table[j]; b = bit_alloc[0][i]; if (b) { int mant, scale0, scale1; scale0 = scale_factors[0][i][k]; scale1 = scale_factors[1][i][k]; qindex = alloc_table[j+b]; bits = quant_bits[qindex]; if (bits < 0) { /* 3 values at the same time */ v = get_bits(&s->gb, -bits); steps = quant_steps[qindex]; mant = v % steps; v = v / steps; s->sb_samples[0][k * 12 + l + 0][i] = l2_unscale_group(steps, mant, scale0); s->sb_samples[1][k * 12 + l + 0][i] = l2_unscale_group(steps, mant, scale1); mant = v % steps; v = v / steps; s->sb_samples[0][k * 12 + l + 1][i] = l2_unscale_group(steps, mant, scale0); s->sb_samples[1][k * 12 + l + 1][i] = l2_unscale_group(steps, mant, scale1); s->sb_samples[0][k * 12 + l + 2][i] = l2_unscale_group(steps, v, scale0); s->sb_samples[1][k * 12 + l + 2][i] = l2_unscale_group(steps, v, scale1); } else { for(m=0;m<3;m++) { mant = get_bits(&s->gb, bits); s->sb_samples[0][k * 12 + l + m][i] = l1_unscale(bits - 1, mant, scale0); s->sb_samples[1][k * 12 + l + m][i] = l1_unscale(bits - 1, mant, scale1); } } } else { s->sb_samples[0][k * 12 + l + 0][i] = 0; s->sb_samples[0][k * 12 + l + 1][i] = 0; s->sb_samples[0][k * 12 + l + 2][i] = 0; s->sb_samples[1][k * 12 + l + 0][i] = 0; s->sb_samples[1][k * 12 + l + 1][i] = 0; s->sb_samples[1][k * 12 + l + 2][i] = 0; } /* next subband in alloc table */ j += 1 << bit_alloc_bits; } /* fill remaining samples to zero */ for(i=sblimit;i<SBLIMIT;i++) { for(ch=0;ch<s->nb_channels;ch++) { s->sb_samples[ch][k * 12 + l + 0][i] = 0; s->sb_samples[ch][k * 12 + l + 1][i] = 0; s->sb_samples[ch][k * 12 + l + 2][i] = 0; } } } } return 3 * 12; } /* * Seek back in the stream for backstep bytes (at most 511 bytes) */ static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep) { uint8_t *ptr; /* compute current position in stream */ ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3); /* copy old data before current one */ ptr -= backstep; memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] + BACKSTEP_SIZE + s->old_frame_size - backstep, backstep); /* init get bits again */ init_get_bits(&s->gb, ptr, (s->frame_size + backstep)*8); /* prepare next buffer */ s->inbuf_index ^= 1; s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE]; s->old_frame_size = s->frame_size; } static inline void lsf_sf_expand(int *slen, int sf, int n1, int n2, int n3) { if (n3) { slen[3] = sf % n3; sf /= n3; } else { slen[3] = 0; } if (n2) { slen[2] = sf % n2; sf /= n2; } else { slen[2] = 0; } slen[1] = sf % n1; sf /= n1; slen[0] = sf; } static void exponents_from_scale_factors(MPADecodeContext *s, GranuleDef *g, int16_t *exponents) { const uint8_t *bstab, *pretab; int len, i, j, k, l, v0, shift, gain, gains[3]; int16_t *exp_ptr; exp_ptr = exponents; gain = g->global_gain - 210; shift = g->scalefac_scale + 1; bstab = band_size_long[s->sample_rate_index]; pretab = mpa_pretab[g->preflag]; for(i=0;i<g->long_end;i++) { v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift); len = bstab[i]; for(j=len;j>0;j--) *exp_ptr++ = v0; } if (g->short_start < 13) { bstab = band_size_short[s->sample_rate_index]; gains[0] = gain - (g->subblock_gain[0] << 3); gains[1] = gain - (g->subblock_gain[1] << 3); gains[2] = gain - (g->subblock_gain[2] << 3); k = g->long_end; for(i=g->short_start;i<13;i++) { len = bstab[i]; for(l=0;l<3;l++) { v0 = gains[l] - (g->scale_factors[k++] << shift); for(j=len;j>0;j--) *exp_ptr++ = v0; } } } } /* handle n = 0 too */ static inline int get_bitsz(GetBitContext *s, int n) { if (n == 0) return 0; else return get_bits(s, n); } static int huffman_decode(MPADecodeContext *s, GranuleDef *g, int16_t *exponents, int end_pos) { int s_index; int linbits, code, x, y, l, v, i, j, k, pos; GetBitContext last_gb; VLC *vlc; uint8_t *code_table; /* low frequencies (called big values) */ s_index = 0; for(i=0;i<3;i++) { j = g->region_size[i]; if (j == 0) continue; /* select vlc table */ k = g->table_select[i]; l = mpa_huff_data[k][0]; linbits = mpa_huff_data[k][1]; vlc = &huff_vlc[l]; code_table = huff_code_table[l]; /* read huffcode and compute each couple */ for(;j>0;j--) { if (get_bits_count(&s->gb) >= end_pos) break; if (code_table) { code = get_vlc(&s->gb, vlc); if (code < 0) return -1; y = code_table[code]; x = y >> 4; y = y & 0x0f; } else { x = 0; y = 0; } dprintf("region=%d n=%d x=%d y=%d exp=%d\n", i, g->region_size[i] - j, x, y, exponents[s_index]); if (x) { if (x == 15) x += get_bitsz(&s->gb, linbits); v = l3_unscale(x, exponents[s_index]); if (get_bits1(&s->gb)) v = -v; } else { v = 0; } g->sb_hybrid[s_index++] = v; if (y) { if (y == 15) y += get_bitsz(&s->gb, linbits); v = l3_unscale(y, exponents[s_index]); if (get_bits1(&s->gb)) v = -v; } else { v = 0; } g->sb_hybrid[s_index++] = v; } } /* high frequencies */ vlc = &huff_quad_vlc[g->count1table_select]; last_gb.buffer = NULL; while (s_index <= 572) { pos = get_bits_count(&s->gb); if (pos >= end_pos) { if (pos > end_pos && last_gb.buffer != NULL) { /* some encoders generate an incorrect size for this part. We must go back into the data */ s_index -= 4; s->gb = last_gb; } break; } last_gb= s->gb; code = get_vlc(&s->gb, vlc); dprintf("t=%d code=%d\n", g->count1table_select, code); if (code < 0) return -1; for(i=0;i<4;i++) { if (code & (8 >> i)) { /* non zero value. Could use a hand coded function for 'one' value */ v = l3_unscale(1, exponents[s_index]); if(get_bits1(&s->gb)) v = -v; } else { v = 0; } g->sb_hybrid[s_index++] = v; } } while (s_index < 576) g->sb_hybrid[s_index++] = 0; return 0; } /* Reorder short blocks from bitstream order to interleaved order. It would be faster to do it in parsing, but the code would be far more complicated */ static void reorder_block(MPADecodeContext *s, GranuleDef *g) { int i, j, k, len; int32_t *ptr, *dst, *ptr1; int32_t tmp[576]; if (g->block_type != 2) return; if (g->switch_point) { if (s->sample_rate_index != 8) { ptr = g->sb_hybrid + 36; } else { ptr = g->sb_hybrid + 48; } } else { ptr = g->sb_hybrid; } for(i=g->short_start;i<13;i++) { len = band_size_short[s->sample_rate_index][i]; ptr1 = ptr; for(k=0;k<3;k++) { dst = tmp + k; for(j=len;j>0;j--) { *dst = *ptr++; dst += 3; } } memcpy(ptr1, tmp, len * 3 * sizeof(int32_t)); } } #define ISQRT2 FIXR(0.70710678118654752440) static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1) { int i, j, k, l; int32_t v1, v2; int sf_max, tmp0, tmp1, sf, len, non_zero_found; int32_t (*is_tab)[16]; int32_t *tab0, *tab1; int non_zero_found_short[3]; /* intensity stereo */ if (s->mode_ext & MODE_EXT_I_STEREO) { if (!s->lsf) { is_tab = is_table; sf_max = 7; } else { is_tab = is_table_lsf[g1->scalefac_compress & 1]; sf_max = 16; } tab0 = g0->sb_hybrid + 576; tab1 = g1->sb_hybrid + 576; non_zero_found_short[0] = 0; non_zero_found_short[1] = 0; non_zero_found_short[2] = 0; k = (13 - g1->short_start) * 3 + g1->long_end - 3; for(i = 12;i >= g1->short_start;i--) { /* for last band, use previous scale factor */ if (i != 11) k -= 3; len = band_size_short[s->sample_rate_index][i]; for(l=2;l>=0;l--) { tab0 -= len; tab1 -= len; if (!non_zero_found_short[l]) { /* test if non zero band. if so, stop doing i-stereo */ for(j=0;j<len;j++) { if (tab1[j] != 0) { non_zero_found_short[l] = 1; goto found1; } } sf = g1->scale_factors[k + l]; if (sf >= sf_max) goto found1; v1 = is_tab[0][sf]; v2 = is_tab[1][sf]; for(j=0;j<len;j++) { tmp0 = tab0[j]; tab0[j] = MULL(tmp0, v1); tab1[j] = MULL(tmp0, v2); } } else { found1: if (s->mode_ext & MODE_EXT_MS_STEREO) { /* lower part of the spectrum : do ms stereo if enabled */ for(j=0;j<len;j++) { tmp0 = tab0[j]; tmp1 = tab1[j]; tab0[j] = MULL(tmp0 + tmp1, ISQRT2); tab1[j] = MULL(tmp0 - tmp1, ISQRT2); } } } } } non_zero_found = non_zero_found_short[0] | non_zero_found_short[1] | non_zero_found_short[2]; for(i = g1->long_end - 1;i >= 0;i--) { len = band_size_long[s->sample_rate_index][i]; tab0 -= len; tab1 -= len; /* test if non zero band. if so, stop doing i-stereo */ if (!non_zero_found) { for(j=0;j<len;j++) { if (tab1[j] != 0) { non_zero_found = 1; goto found2; } } /* for last band, use previous scale factor */ k = (i == 21) ? 20 : i; sf = g1->scale_factors[k]; if (sf >= sf_max) goto found2; v1 = is_tab[0][sf]; v2 = is_tab[1][sf]; for(j=0;j<len;j++) { tmp0 = tab0[j]; tab0[j] = MULL(tmp0, v1); tab1[j] = MULL(tmp0, v2); } } else { found2: if (s->mode_ext & MODE_EXT_MS_STEREO) { /* lower part of the spectrum : do ms stereo if enabled */ for(j=0;j<len;j++) { tmp0 = tab0[j]; tmp1 = tab1[j]; tab0[j] = MULL(tmp0 + tmp1, ISQRT2); tab1[j] = MULL(tmp0 - tmp1, ISQRT2); } } } } } else if (s->mode_ext & MODE_EXT_MS_STEREO) { /* ms stereo ONLY */ /* NOTE: the 1/sqrt(2) normalization factor is included in the global gain */ tab0 = g0->sb_hybrid; tab1 = g1->sb_hybrid; for(i=0;i<576;i++) { tmp0 = tab0[i]; tmp1 = tab1[i]; tab0[i] = tmp0 + tmp1; tab1[i] = tmp0 - tmp1; } } } static void compute_antialias(MPADecodeContext *s, GranuleDef *g) { int32_t *ptr, *p0, *p1, *csa; int n, tmp0, tmp1, i, j; /* we antialias only "long" bands */ if (g->block_type == 2) { if (!g->switch_point) return; /* XXX: check this for 8000Hz case */ n = 1; } else { n = SBLIMIT - 1; } ptr = g->sb_hybrid + 18; for(i = n;i > 0;i--) { p0 = ptr - 1; p1 = ptr; csa = &csa_table[0][0]; for(j=0;j<8;j++) { tmp0 = *p0; tmp1 = *p1; *p0 = FRAC_RND(MUL64(tmp0, csa[0]) - MUL64(tmp1, csa[1])); *p1 = FRAC_RND(MUL64(tmp0, csa[1]) + MUL64(tmp1, csa[0])); p0--; p1++; csa += 2; } ptr += 18; } } static void compute_imdct(MPADecodeContext *s, GranuleDef *g, int32_t *sb_samples, int32_t *mdct_buf) { int32_t *ptr, *win, *win1, *buf, *buf2, *out_ptr, *ptr1; int32_t in[6]; int32_t out[36]; int32_t out2[12]; int i, j, k, mdct_long_end, v, sblimit; /* find last non zero block */ ptr = g->sb_hybrid + 576; ptr1 = g->sb_hybrid + 2 * 18; while (ptr >= ptr1) { ptr -= 6; v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5]; if (v != 0) break; } sblimit = ((ptr - g->sb_hybrid) / 18) + 1; if (g->block_type == 2) { /* XXX: check for 8000 Hz */ if (g->switch_point) mdct_long_end = 2; else mdct_long_end = 0; } else { mdct_long_end = sblimit; } buf = mdct_buf; ptr = g->sb_hybrid; for(j=0;j<mdct_long_end;j++) { imdct36(out, ptr); /* apply window & overlap with previous buffer */ out_ptr = sb_samples + j; /* select window */ if (g->switch_point && j < 2) win1 = mdct_win[0]; else win1 = mdct_win[g->block_type]; /* select frequency inversion */ win = win1 + ((4 * 36) & -(j & 1)); for(i=0;i<18;i++) { *out_ptr = MULL(out[i], win[i]) + buf[i]; buf[i] = MULL(out[i + 18], win[i + 18]); out_ptr += SBLIMIT; } ptr += 18; buf += 18; } for(j=mdct_long_end;j<sblimit;j++) { for(i=0;i<6;i++) { out[i] = 0; out[6 + i] = 0; out[30+i] = 0; } /* select frequency inversion */ win = mdct_win[2] + ((4 * 36) & -(j & 1)); buf2 = out + 6; for(k=0;k<3;k++) { /* reorder input for short mdct */ ptr1 = ptr + k; for(i=0;i<6;i++) { in[i] = *ptr1; ptr1 += 3; } imdct12(out2, in); /* apply 12 point window and do small overlap */ for(i=0;i<6;i++) { buf2[i] = MULL(out2[i], win[i]) + buf2[i]; buf2[i + 6] = MULL(out2[i + 6], win[i + 6]); } buf2 += 6; } /* overlap */ out_ptr = sb_samples + j; for(i=0;i<18;i++) { *out_ptr = out[i] + buf[i]; buf[i] = out[i + 18]; out_ptr += SBLIMIT; } ptr += 18; buf += 18; } /* zero bands */ for(j=sblimit;j<SBLIMIT;j++) { /* overlap */ out_ptr = sb_samples + j; for(i=0;i<18;i++) { *out_ptr = buf[i]; buf[i] = 0; out_ptr += SBLIMIT; } buf += 18; } } #if defined(DEBUG) void sample_dump(int fnum, int32_t *tab, int n) { static FILE *files[16], *f; char buf[512]; int i; int32_t v; f = files[fnum]; if (!f) { sprintf(buf, "/tmp/out%d.%s.pcm", fnum, #ifdef USE_HIGHPRECISION "hp" #else "lp" #endif ); f = fopen(buf, "w"); if (!f) return; files[fnum] = f; } if (fnum == 0) { static int pos = 0; printf("pos=%d\n", pos); for(i=0;i<n;i++) { printf(" %0.4f", (double)tab[i] / FRAC_ONE); if ((i % 18) == 17) printf("\n"); } pos += n; } for(i=0;i<n;i++) { /* normalize to 23 frac bits */ v = tab[i] << (23 - FRAC_BITS); fwrite(&v, 1, sizeof(int32_t), f); } } #endif /* main layer3 decoding function */ static int mp_decode_layer3(MPADecodeContext *s) { int nb_granules, main_data_begin, private_bits; int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left; GranuleDef granules[2][2], *g; int16_t exponents[576]; /* read side info */ if (s->lsf) { main_data_begin = get_bits(&s->gb, 8); if (s->nb_channels == 2) private_bits = get_bits(&s->gb, 2); else private_bits = get_bits(&s->gb, 1); nb_granules = 1; } else { main_data_begin = get_bits(&s->gb, 9); if (s->nb_channels == 2) private_bits = get_bits(&s->gb, 3); else private_bits = get_bits(&s->gb, 5); nb_granules = 2; for(ch=0;ch<s->nb_channels;ch++) { granules[ch][0].scfsi = 0; /* all scale factors are transmitted */ granules[ch][1].scfsi = get_bits(&s->gb, 4); } } for(gr=0;gr<nb_granules;gr++) { for(ch=0;ch<s->nb_channels;ch++) { dprintf("gr=%d ch=%d: side_info\n", gr, ch); g = &granules[ch][gr]; g->part2_3_length = get_bits(&s->gb, 12); g->big_values = get_bits(&s->gb, 9); g->global_gain = get_bits(&s->gb, 8); /* if MS stereo only is selected, we precompute the 1/sqrt(2) renormalization factor */ if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) == MODE_EXT_MS_STEREO) g->global_gain -= 2; if (s->lsf) g->scalefac_compress = get_bits(&s->gb, 9); else g->scalefac_compress = get_bits(&s->gb, 4); blocksplit_flag = get_bits(&s->gb, 1); if (blocksplit_flag) { g->block_type = get_bits(&s->gb, 2); if (g->block_type == 0) return -1; g->switch_point = get_bits(&s->gb, 1); for(i=0;i<2;i++) g->table_select[i] = get_bits(&s->gb, 5); for(i=0;i<3;i++) g->subblock_gain[i] = get_bits(&s->gb, 3); /* compute huffman coded region sizes */ if (g->block_type == 2) g->region_size[0] = (36 / 2); else { if (s->sample_rate_index <= 2) g->region_size[0] = (36 / 2); else if (s->sample_rate_index != 8) g->region_size[0] = (54 / 2); else g->region_size[0] = (108 / 2); } g->region_size[1] = (576 / 2); } else { int region_address1, region_address2, l; g->block_type = 0; g->switch_point = 0; for(i=0;i<3;i++) g->table_select[i] = get_bits(&s->gb, 5); /* compute huffman coded region sizes */ region_address1 = get_bits(&s->gb, 4); region_address2 = get_bits(&s->gb, 3); dprintf("region1=%d region2=%d\n", region_address1, region_address2); g->region_size[0] = band_index_long[s->sample_rate_index][region_address1 + 1] >> 1; l = region_address1 + region_address2 + 2; /* should not overflow */ if (l > 22) l = 22; g->region_size[1] = band_index_long[s->sample_rate_index][l] >> 1; } /* convert region offsets to region sizes and truncate size to big_values */ g->region_size[2] = (576 / 2); j = 0; for(i=0;i<3;i++) { k = g->region_size[i]; if (k > g->big_values) k = g->big_values; g->region_size[i] = k - j; j = k; } /* compute band indexes */ if (g->block_type == 2) { if (g->switch_point) { /* if switched mode, we handle the 36 first samples as long blocks. For 8000Hz, we handle the 48 first exponents as long blocks (XXX: check this!) */ if (s->sample_rate_index <= 2) g->long_end = 8; else if (s->sample_rate_index != 8) g->long_end = 6; else g->long_end = 4; /* 8000 Hz */ if (s->sample_rate_index != 8) g->short_start = 3; else g->short_start = 2; } else { g->long_end = 0; g->short_start = 0; } } else { g->short_start = 13; g->long_end = 22; } g->preflag = 0; if (!s->lsf) g->preflag = get_bits(&s->gb, 1); g->scalefac_scale = get_bits(&s->gb, 1); g->count1table_select = get_bits(&s->gb, 1); dprintf("block_type=%d switch_point=%d\n", g->block_type, g->switch_point); } } /* now we get bits from the main_data_begin offset */ dprintf("seekback: %d\n", main_data_begin); seek_to_maindata(s, main_data_begin); for(gr=0;gr<nb_granules;gr++) { for(ch=0;ch<s->nb_channels;ch++) { g = &granules[ch][gr]; bits_pos = get_bits_count(&s->gb); if (!s->lsf) { uint8_t *sc; int slen, slen1, slen2; /* MPEG1 scale factors */ slen1 = slen_table[0][g->scalefac_compress]; slen2 = slen_table[1][g->scalefac_compress]; dprintf("slen1=%d slen2=%d\n", slen1, slen2); if (g->block_type == 2) { n = g->switch_point ? 17 : 18; j = 0; for(i=0;i<n;i++) g->scale_factors[j++] = get_bitsz(&s->gb, slen1); for(i=0;i<18;i++) g->scale_factors[j++] = get_bitsz(&s->gb, slen2); for(i=0;i<3;i++) g->scale_factors[j++] = 0; } else { sc = granules[ch][0].scale_factors; j = 0; for(k=0;k<4;k++) { n = (k == 0 ? 6 : 5); if ((g->scfsi & (0x8 >> k)) == 0) { slen = (k < 2) ? slen1 : slen2; for(i=0;i<n;i++) g->scale_factors[j++] = get_bitsz(&s->gb, slen); } else { /* simply copy from last granule */ for(i=0;i<n;i++) { g->scale_factors[j] = sc[j]; j++; } } } g->scale_factors[j++] = 0; } #if defined(DEBUG) { printf("scfsi=%x gr=%d ch=%d scale_factors:\n", g->scfsi, gr, ch); for(i=0;i<j;i++) printf(" %d", g->scale_factors[i]); printf("\n"); } #endif } else { int tindex, tindex2, slen[4], sl, sf; /* LSF scale factors */ if (g->block_type == 2) { tindex = g->switch_point ? 2 : 1; } else { tindex = 0; } sf = g->scalefac_compress; if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) { /* intensity stereo case */ sf >>= 1; if (sf < 180) { lsf_sf_expand(slen, sf, 6, 6, 0); tindex2 = 3; } else if (sf < 244) { lsf_sf_expand(slen, sf - 180, 4, 4, 0); tindex2 = 4; } else { lsf_sf_expand(slen, sf - 244, 3, 0, 0); tindex2 = 5; } } else { /* normal case */ if (sf < 400) { lsf_sf_expand(slen, sf, 5, 4, 4); tindex2 = 0; } else if (sf < 500) { lsf_sf_expand(slen, sf - 400, 5, 4, 0); tindex2 = 1; } else { lsf_sf_expand(slen, sf - 500, 3, 0, 0); tindex2 = 2; g->preflag = 1; } } j = 0; for(k=0;k<4;k++) { n = lsf_nsf_table[tindex2][tindex][k]; sl = slen[k]; for(i=0;i<n;i++) g->scale_factors[j++] = get_bitsz(&s->gb, sl); } /* XXX: should compute exact size */ for(;j<40;j++) g->scale_factors[j] = 0; #if defined(DEBUG) { printf("gr=%d ch=%d scale_factors:\n", gr, ch); for(i=0;i<40;i++) printf(" %d", g->scale_factors[i]); printf("\n"); } #endif } exponents_from_scale_factors(s, g, exponents); /* read Huffman coded residue */ if (huffman_decode(s, g, exponents, bits_pos + g->part2_3_length) < 0) return -1; #if defined(DEBUG) sample_dump(0, g->sb_hybrid, 576); #endif /* skip extension bits */ bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos); if (bits_left < 0) { dprintf("bits_left=%d\n", bits_left); return -1; } while (bits_left >= 16) { skip_bits(&s->gb, 16); bits_left -= 16; } if (bits_left > 0) skip_bits(&s->gb, bits_left); } /* ch */ if (s->nb_channels == 2) compute_stereo(s, &granules[0][gr], &granules[1][gr]); for(ch=0;ch<s->nb_channels;ch++) { g = &granules[ch][gr]; reorder_block(s, g); #if defined(DEBUG) sample_dump(0, g->sb_hybrid, 576); #endif compute_antialias(s, g); #if defined(DEBUG) sample_dump(1, g->sb_hybrid, 576); #endif compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]); #if defined(DEBUG) sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576); #endif } } /* gr */ return nb_granules * 18; } static int mp_decode_frame(MPADecodeContext *s, short *samples) { int i, nb_frames, ch; short *samples_ptr; init_get_bits(&s->gb, s->inbuf + HEADER_SIZE, (s->inbuf_ptr - s->inbuf - HEADER_SIZE)*8); /* skip error protection field */ if (s->error_protection) get_bits(&s->gb, 16); dprintf("frame %d:\n", s->frame_count); switch(s->layer) { case 1: nb_frames = mp_decode_layer1(s); break; case 2: nb_frames = mp_decode_layer2(s); break; case 3: default: nb_frames = mp_decode_layer3(s); break; } #if defined(DEBUG) for(i=0;i<nb_frames;i++) { for(ch=0;ch<s->nb_channels;ch++) { int j; printf("%d-%d:", i, ch); for(j=0;j<SBLIMIT;j++) printf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE); printf("\n"); } } #endif /* apply the synthesis filter */ for(ch=0;ch<s->nb_channels;ch++) { samples_ptr = samples + ch; for(i=0;i<nb_frames;i++) { synth_filter(s, ch, samples_ptr, s->nb_channels, s->sb_samples[ch][i]); samples_ptr += 32 * s->nb_channels; } } #ifdef DEBUG s->frame_count++; #endif return nb_frames * 32 * sizeof(short) * s->nb_channels; } static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t * buf, int buf_size) { MPADecodeContext *s = avctx->priv_data; uint32_t header; uint8_t *buf_ptr; int len, out_size; short *out_samples = data; *data_size = 0; buf_ptr = buf; while (buf_size > 0) { len = s->inbuf_ptr - s->inbuf; if (s->frame_size == 0) { /* special case for next header for first frame in free format case (XXX: find a simpler method) */ if (s->free_format_next_header != 0) { s->inbuf[0] = s->free_format_next_header >> 24; s->inbuf[1] = s->free_format_next_header >> 16; s->inbuf[2] = s->free_format_next_header >> 8; s->inbuf[3] = s->free_format_next_header; s->inbuf_ptr = s->inbuf + 4; s->free_format_next_header = 0; goto got_header; } /* no header seen : find one. We need at least HEADER_SIZE bytes to parse it */ len = HEADER_SIZE - len; if (len > buf_size) len = buf_size; if (len > 0) { memcpy(s->inbuf_ptr, buf_ptr, len); buf_ptr += len; buf_size -= len; s->inbuf_ptr += len; } if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) { got_header: header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) | (s->inbuf[2] << 8) | s->inbuf[3]; if (check_header(header) < 0) { /* no sync found : move by one byte (inefficient, but simple!) */ memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1); s->inbuf_ptr--; dprintf("skip %x\n", header); /* reset free format frame size to give a chance to get a new bitrate */ s->free_format_frame_size = 0; } else { if (decode_header(s, header) == 1) { /* free format: prepare to compute frame size */ s->frame_size = -1; } /* update codec info */ avctx->sample_rate = s->sample_rate; avctx->channels = s->nb_channels; avctx->bit_rate = s->bit_rate; avctx->frame_size = s->frame_size; } } } else if (s->frame_size == -1) { /* free format : find next sync to compute frame size */ len = MPA_MAX_CODED_FRAME_SIZE - len; if (len > buf_size) len = buf_size; if (len == 0) { /* frame too long: resync */ s->frame_size = 0; memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1); s->inbuf_ptr--; } else { uint8_t *p, *pend; uint32_t header1; int padding; memcpy(s->inbuf_ptr, buf_ptr, len); /* check for header */ p = s->inbuf_ptr - 3; pend = s->inbuf_ptr + len - 4; while (p <= pend) { header = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]; header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) | (s->inbuf[2] << 8) | s->inbuf[3]; /* check with high probability that we have a valid header */ if ((header & SAME_HEADER_MASK) == (header1 & SAME_HEADER_MASK)) { /* header found: update pointers */ len = (p + 4) - s->inbuf_ptr; buf_ptr += len; buf_size -= len; s->inbuf_ptr = p; /* compute frame size */ s->free_format_next_header = header; s->free_format_frame_size = s->inbuf_ptr - s->inbuf; padding = (header1 >> 9) & 1; if (s->layer == 1) s->free_format_frame_size -= padding * 4; else s->free_format_frame_size -= padding; dprintf("free frame size=%d padding=%d\n", s->free_format_frame_size, padding); decode_header(s, header1); goto next_data; } p++; } /* not found: simply increase pointers */ buf_ptr += len; s->inbuf_ptr += len; buf_size -= len; } } else if (len < s->frame_size) { if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE) s->frame_size = MPA_MAX_CODED_FRAME_SIZE; len = s->frame_size - len; if (len > buf_size) len = buf_size; memcpy(s->inbuf_ptr, buf_ptr, len); buf_ptr += len; s->inbuf_ptr += len; buf_size -= len; } else { out_size = mp_decode_frame(s, out_samples); s->inbuf_ptr = s->inbuf; s->frame_size = 0; *data_size = out_size; break; } next_data: ; } return buf_ptr - buf; } AVCodec mp2_decoder = { "mp2", CODEC_TYPE_AUDIO, CODEC_ID_MP2, sizeof(MPADecodeContext), decode_init, NULL, NULL, decode_frame, }; AVCodec mp3_decoder = { "mp3", CODEC_TYPE_AUDIO, CODEC_ID_MP3LAME, sizeof(MPADecodeContext), decode_init, NULL, NULL, decode_frame, }; #undef C1 #undef C2 #undef C3 #undef C4 #undef C5 #undef C6 #undef C7 #undef C8 #undef FRAC_BITS #undef HEADER_SIZE