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Diffstat (limited to '')
| -rw-r--r-- | src/libmad/layer3.c | 2502 |
1 files changed, 2502 insertions, 0 deletions
diff --git a/src/libmad/layer3.c b/src/libmad/layer3.c new file mode 100644 index 000000000..e1b073c71 --- /dev/null +++ b/src/libmad/layer3.c @@ -0,0 +1,2502 @@ +/* + * libmad - MPEG audio decoder library + * Copyright (C) 2000-2003 Underbit Technologies, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * $Id: layer3.c,v 1.1 2003/08/14 03:57:13 shank Exp $ + */ + +# ifdef HAVE_CONFIG_H +# include "config.h" +# endif + +# include "global.h" + +# include <stdlib.h> +# include <string.h> + +# ifdef HAVE_ASSERT_H +# include <assert.h> +# endif + +# ifdef HAVE_LIMITS_H +# include <limits.h> +# else +# define CHAR_BIT 8 +# endif + +# include "fixed.h" +# include "bit.h" +# include "stream.h" +# include "frame.h" +# include "huffman.h" +# include "layer3.h" + +/* --- Layer III ----------------------------------------------------------- */ + +enum { + count1table_select = 0x01, + scalefac_scale = 0x02, + preflag = 0x04, + mixed_block_flag = 0x08 +}; + +enum { + I_STEREO = 0x1, + MS_STEREO = 0x2 +}; + +struct sideinfo { + unsigned int main_data_begin; + unsigned int private_bits; + + unsigned char scfsi[2]; + + struct granule { + struct channel { + /* from side info */ + unsigned short part2_3_length; + unsigned short big_values; + unsigned short global_gain; + unsigned short scalefac_compress; + + unsigned char flags; + unsigned char block_type; + unsigned char table_select[3]; + unsigned char subblock_gain[3]; + unsigned char region0_count; + unsigned char region1_count; + + /* from main_data */ + unsigned char scalefac[39]; /* scalefac_l and/or scalefac_s */ + } ch[2]; + } gr[2]; +}; + +/* + * scalefactor bit lengths + * derived from section 2.4.2.7 of ISO/IEC 11172-3 + */ +static +struct { + unsigned char slen1; + unsigned char slen2; +} const sflen_table[16] = { + { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 }, + { 3, 0 }, { 1, 1 }, { 1, 2 }, { 1, 3 }, + { 2, 1 }, { 2, 2 }, { 2, 3 }, { 3, 1 }, + { 3, 2 }, { 3, 3 }, { 4, 2 }, { 4, 3 } +}; + +/* + * number of LSF scalefactor band values + * derived from section 2.4.3.2 of ISO/IEC 13818-3 + */ +static +unsigned char const nsfb_table[6][3][4] = { + { { 6, 5, 5, 5 }, + { 9, 9, 9, 9 }, + { 6, 9, 9, 9 } }, + + { { 6, 5, 7, 3 }, + { 9, 9, 12, 6 }, + { 6, 9, 12, 6 } }, + + { { 11, 10, 0, 0 }, + { 18, 18, 0, 0 }, + { 15, 18, 0, 0 } }, + + { { 7, 7, 7, 0 }, + { 12, 12, 12, 0 }, + { 6, 15, 12, 0 } }, + + { { 6, 6, 6, 3 }, + { 12, 9, 9, 6 }, + { 6, 12, 9, 6 } }, + + { { 8, 8, 5, 0 }, + { 15, 12, 9, 0 }, + { 6, 18, 9, 0 } } +}; + +/* + * MPEG-1 scalefactor band widths + * derived from Table B.8 of ISO/IEC 11172-3 + */ +static +unsigned char const sfb_48000_long[] = { + 4, 4, 4, 4, 4, 4, 6, 6, 6, 8, 10, + 12, 16, 18, 22, 28, 34, 40, 46, 54, 54, 192 +}; + +static +unsigned char const sfb_44100_long[] = { + 4, 4, 4, 4, 4, 4, 6, 6, 8, 8, 10, + 12, 16, 20, 24, 28, 34, 42, 50, 54, 76, 158 +}; + +static +unsigned char const sfb_32000_long[] = { + 4, 4, 4, 4, 4, 4, 6, 6, 8, 10, 12, + 16, 20, 24, 30, 38, 46, 56, 68, 84, 102, 26 +}; + +static +unsigned char const sfb_48000_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, + 6, 6, 6, 6, 6, 10, 10, 10, 12, 12, 12, 14, 14, + 14, 16, 16, 16, 20, 20, 20, 26, 26, 26, 66, 66, 66 +}; + +static +unsigned char const sfb_44100_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, + 6, 6, 8, 8, 8, 10, 10, 10, 12, 12, 12, 14, 14, + 14, 18, 18, 18, 22, 22, 22, 30, 30, 30, 56, 56, 56 +}; + +static +unsigned char const sfb_32000_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, + 6, 6, 8, 8, 8, 12, 12, 12, 16, 16, 16, 20, 20, + 20, 26, 26, 26, 34, 34, 34, 42, 42, 42, 12, 12, 12 +}; + +static +unsigned char const sfb_48000_mixed[] = { + /* long */ 4, 4, 4, 4, 4, 4, 6, 6, + /* short */ 4, 4, 4, 6, 6, 6, 6, 6, 6, 10, + 10, 10, 12, 12, 12, 14, 14, 14, 16, 16, + 16, 20, 20, 20, 26, 26, 26, 66, 66, 66 +}; + +static +unsigned char const sfb_44100_mixed[] = { + /* long */ 4, 4, 4, 4, 4, 4, 6, 6, + /* short */ 4, 4, 4, 6, 6, 6, 8, 8, 8, 10, + 10, 10, 12, 12, 12, 14, 14, 14, 18, 18, + 18, 22, 22, 22, 30, 30, 30, 56, 56, 56 +}; + +static +unsigned char const sfb_32000_mixed[] = { + /* long */ 4, 4, 4, 4, 4, 4, 6, 6, + /* short */ 4, 4, 4, 6, 6, 6, 8, 8, 8, 12, + 12, 12, 16, 16, 16, 20, 20, 20, 26, 26, + 26, 34, 34, 34, 42, 42, 42, 12, 12, 12 +}; + +/* + * MPEG-2 scalefactor band widths + * derived from Table B.2 of ISO/IEC 13818-3 + */ +static +unsigned char const sfb_24000_long[] = { + 6, 6, 6, 6, 6, 6, 8, 10, 12, 14, 16, + 18, 22, 26, 32, 38, 46, 54, 62, 70, 76, 36 +}; + +static +unsigned char const sfb_22050_long[] = { + 6, 6, 6, 6, 6, 6, 8, 10, 12, 14, 16, + 20, 24, 28, 32, 38, 46, 52, 60, 68, 58, 54 +}; + +# define sfb_16000_long sfb_22050_long + +static +unsigned char const sfb_24000_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 8, + 8, 8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18, + 18, 24, 24, 24, 32, 32, 32, 44, 44, 44, 12, 12, 12 +}; + +static +unsigned char const sfb_22050_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 6, + 6, 6, 8, 8, 8, 10, 10, 10, 14, 14, 14, 18, 18, + 18, 26, 26, 26, 32, 32, 32, 42, 42, 42, 18, 18, 18 +}; + +static +unsigned char const sfb_16000_short[] = { + 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 8, + 8, 8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18, + 18, 24, 24, 24, 30, 30, 30, 40, 40, 40, 18, 18, 18 +}; + +static +unsigned char const sfb_24000_mixed[] = { + /* long */ 6, 6, 6, 6, 6, 6, + /* short */ 6, 6, 6, 8, 8, 8, 10, 10, 10, 12, + 12, 12, 14, 14, 14, 18, 18, 18, 24, 24, + 24, 32, 32, 32, 44, 44, 44, 12, 12, 12 +}; + +static +unsigned char const sfb_22050_mixed[] = { + /* long */ 6, 6, 6, 6, 6, 6, + /* short */ 6, 6, 6, 6, 6, 6, 8, 8, 8, 10, + 10, 10, 14, 14, 14, 18, 18, 18, 26, 26, + 26, 32, 32, 32, 42, 42, 42, 18, 18, 18 +}; + +static +unsigned char const sfb_16000_mixed[] = { + /* long */ 6, 6, 6, 6, 6, 6, + /* short */ 6, 6, 6, 8, 8, 8, 10, 10, 10, 12, + 12, 12, 14, 14, 14, 18, 18, 18, 24, 24, + 24, 30, 30, 30, 40, 40, 40, 18, 18, 18 +}; + +/* + * MPEG 2.5 scalefactor band widths + * derived from public sources + */ +# define sfb_12000_long sfb_16000_long +# define sfb_11025_long sfb_12000_long + +static +unsigned char const sfb_8000_long[] = { + 12, 12, 12, 12, 12, 12, 16, 20, 24, 28, 32, + 40, 48, 56, 64, 76, 90, 2, 2, 2, 2, 2 +}; + +# define sfb_12000_short sfb_16000_short +# define sfb_11025_short sfb_12000_short + +static +unsigned char const sfb_8000_short[] = { + 8, 8, 8, 8, 8, 8, 8, 8, 8, 12, 12, 12, 16, + 16, 16, 20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36, + 36, 2, 2, 2, 2, 2, 2, 2, 2, 2, 26, 26, 26 +}; + +# define sfb_12000_mixed sfb_16000_mixed +# define sfb_11025_mixed sfb_12000_mixed + +/* the 8000 Hz short block scalefactor bands do not break after + the first 36 frequency lines, so this is probably wrong */ +static +unsigned char const sfb_8000_mixed[] = { + /* long */ 12, 12, 12, + /* short */ 4, 4, 4, 8, 8, 8, 12, 12, 12, 16, 16, 16, + 20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36, 36, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 26, 26, 26 +}; + +static +struct { + unsigned char const *l; + unsigned char const *s; + unsigned char const *m; +} const sfbwidth_table[9] = { + { sfb_48000_long, sfb_48000_short, sfb_48000_mixed }, + { sfb_44100_long, sfb_44100_short, sfb_44100_mixed }, + { sfb_32000_long, sfb_32000_short, sfb_32000_mixed }, + { sfb_24000_long, sfb_24000_short, sfb_24000_mixed }, + { sfb_22050_long, sfb_22050_short, sfb_22050_mixed }, + { sfb_16000_long, sfb_16000_short, sfb_16000_mixed }, + { sfb_12000_long, sfb_12000_short, sfb_12000_mixed }, + { sfb_11025_long, sfb_11025_short, sfb_11025_mixed }, + { sfb_8000_long, sfb_8000_short, sfb_8000_mixed } +}; + +/* + * scalefactor band preemphasis (used only when preflag is set) + * derived from Table B.6 of ISO/IEC 11172-3 + */ +static +unsigned char const pretab[22] = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0 +}; + +/* + * table for requantization + * + * rq_table[x].mantissa * 2^(rq_table[x].exponent) = x^(4/3) + */ +static +struct fixedfloat { + unsigned long mantissa : 27; + unsigned short exponent : 5; +} const rq_table[8207] = { +# include "rq_table.dat" +}; + +/* + * fractional powers of two + * used for requantization and joint stereo decoding + * + * root_table[3 + x] = 2^(x/4) + */ +static +mad_fixed_t const root_table[7] = { + MAD_F(0x09837f05) /* 2^(-3/4) == 0.59460355750136 */, + MAD_F(0x0b504f33) /* 2^(-2/4) == 0.70710678118655 */, + MAD_F(0x0d744fcd) /* 2^(-1/4) == 0.84089641525371 */, + MAD_F(0x10000000) /* 2^( 0/4) == 1.00000000000000 */, + MAD_F(0x1306fe0a) /* 2^(+1/4) == 1.18920711500272 */, + MAD_F(0x16a09e66) /* 2^(+2/4) == 1.41421356237310 */, + MAD_F(0x1ae89f99) /* 2^(+3/4) == 1.68179283050743 */ +}; + +/* + * coefficients for aliasing reduction + * derived from Table B.9 of ISO/IEC 11172-3 + * + * c[] = { -0.6, -0.535, -0.33, -0.185, -0.095, -0.041, -0.0142, -0.0037 } + * cs[i] = 1 / sqrt(1 + c[i]^2) + * ca[i] = c[i] / sqrt(1 + c[i]^2) + */ +static +mad_fixed_t const cs[8] = { + +MAD_F(0x0db84a81) /* +0.857492926 */, +MAD_F(0x0e1b9d7f) /* +0.881741997 */, + +MAD_F(0x0f31adcf) /* +0.949628649 */, +MAD_F(0x0fbba815) /* +0.983314592 */, + +MAD_F(0x0feda417) /* +0.995517816 */, +MAD_F(0x0ffc8fc8) /* +0.999160558 */, + +MAD_F(0x0fff964c) /* +0.999899195 */, +MAD_F(0x0ffff8d3) /* +0.999993155 */ +}; + +static +mad_fixed_t const ca[8] = { + -MAD_F(0x083b5fe7) /* -0.514495755 */, -MAD_F(0x078c36d2) /* -0.471731969 */, + -MAD_F(0x05039814) /* -0.313377454 */, -MAD_F(0x02e91dd1) /* -0.181913200 */, + -MAD_F(0x0183603a) /* -0.094574193 */, -MAD_F(0x00a7cb87) /* -0.040965583 */, + -MAD_F(0x003a2847) /* -0.014198569 */, -MAD_F(0x000f27b4) /* -0.003699975 */ +}; + +/* + * IMDCT coefficients for short blocks + * derived from section 2.4.3.4.10.2 of ISO/IEC 11172-3 + * + * imdct_s[i/even][k] = cos((PI / 24) * (2 * (i / 2) + 7) * (2 * k + 1)) + * imdct_s[i /odd][k] = cos((PI / 24) * (2 * (6 + (i-1)/2) + 7) * (2 * k + 1)) + */ +static +mad_fixed_t const imdct_s[6][6] = { +# include "imdct_s.dat" +}; + +# if !defined(ASO_IMDCT) +/* + * windowing coefficients for long blocks + * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3 + * + * window_l[i] = sin((PI / 36) * (i + 1/2)) + */ +static +mad_fixed_t const window_l[36] = { + MAD_F(0x00b2aa3e) /* 0.043619387 */, MAD_F(0x0216a2a2) /* 0.130526192 */, + MAD_F(0x03768962) /* 0.216439614 */, MAD_F(0x04cfb0e2) /* 0.300705800 */, + MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x07635284) /* 0.461748613 */, + MAD_F(0x0898c779) /* 0.537299608 */, MAD_F(0x09bd7ca0) /* 0.608761429 */, + MAD_F(0x0acf37ad) /* 0.675590208 */, MAD_F(0x0bcbe352) /* 0.737277337 */, + MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x0d7e8807) /* 0.843391446 */, + + MAD_F(0x0e313245) /* 0.887010833 */, MAD_F(0x0ec835e8) /* 0.923879533 */, + MAD_F(0x0f426cb5) /* 0.953716951 */, MAD_F(0x0f9ee890) /* 0.976296007 */, + MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ffc19fd) /* 0.999048222 */, + MAD_F(0x0ffc19fd) /* 0.999048222 */, MAD_F(0x0fdcf549) /* 0.991444861 */, + MAD_F(0x0f9ee890) /* 0.976296007 */, MAD_F(0x0f426cb5) /* 0.953716951 */, + MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0e313245) /* 0.887010833 */, + + MAD_F(0x0d7e8807) /* 0.843391446 */, MAD_F(0x0cb19346) /* 0.793353340 */, + MAD_F(0x0bcbe352) /* 0.737277337 */, MAD_F(0x0acf37ad) /* 0.675590208 */, + MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0898c779) /* 0.537299608 */, + MAD_F(0x07635284) /* 0.461748613 */, MAD_F(0x061f78aa) /* 0.382683432 */, + MAD_F(0x04cfb0e2) /* 0.300705800 */, MAD_F(0x03768962) /* 0.216439614 */, + MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x00b2aa3e) /* 0.043619387 */, +}; +# endif /* ASO_IMDCT */ + +/* + * windowing coefficients for short blocks + * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3 + * + * window_s[i] = sin((PI / 12) * (i + 1/2)) + */ +static +mad_fixed_t const window_s[12] = { + MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x061f78aa) /* 0.382683432 */, + MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0cb19346) /* 0.793353340 */, + MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0fdcf549) /* 0.991444861 */, + MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ec835e8) /* 0.923879533 */, + MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x09bd7ca0) /* 0.608761429 */, + MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x0216a2a2) /* 0.130526192 */, +}; + +/* + * coefficients for intensity stereo processing + * derived from section 2.4.3.4.9.3 of ISO/IEC 11172-3 + * + * is_ratio[i] = tan(i * (PI / 12)) + * is_table[i] = is_ratio[i] / (1 + is_ratio[i]) + */ +static +mad_fixed_t const is_table[7] = { + MAD_F(0x00000000) /* 0.000000000 */, + MAD_F(0x0361962f) /* 0.211324865 */, + MAD_F(0x05db3d74) /* 0.366025404 */, + MAD_F(0x08000000) /* 0.500000000 */, + MAD_F(0x0a24c28c) /* 0.633974596 */, + MAD_F(0x0c9e69d1) /* 0.788675135 */, + MAD_F(0x10000000) /* 1.000000000 */ +}; + +/* + * coefficients for LSF intensity stereo processing + * derived from section 2.4.3.2 of ISO/IEC 13818-3 + * + * is_lsf_table[0][i] = (1 / sqrt(sqrt(2)))^(i + 1) + * is_lsf_table[1][i] = (1 / sqrt(2)) ^(i + 1) + */ +static +mad_fixed_t const is_lsf_table[2][15] = { + { + MAD_F(0x0d744fcd) /* 0.840896415 */, + MAD_F(0x0b504f33) /* 0.707106781 */, + MAD_F(0x09837f05) /* 0.594603558 */, + MAD_F(0x08000000) /* 0.500000000 */, + MAD_F(0x06ba27e6) /* 0.420448208 */, + MAD_F(0x05a8279a) /* 0.353553391 */, + MAD_F(0x04c1bf83) /* 0.297301779 */, + MAD_F(0x04000000) /* 0.250000000 */, + MAD_F(0x035d13f3) /* 0.210224104 */, + MAD_F(0x02d413cd) /* 0.176776695 */, + MAD_F(0x0260dfc1) /* 0.148650889 */, + MAD_F(0x02000000) /* 0.125000000 */, + MAD_F(0x01ae89fa) /* 0.105112052 */, + MAD_F(0x016a09e6) /* 0.088388348 */, + MAD_F(0x01306fe1) /* 0.074325445 */ + }, { + MAD_F(0x0b504f33) /* 0.707106781 */, + MAD_F(0x08000000) /* 0.500000000 */, + MAD_F(0x05a8279a) /* 0.353553391 */, + MAD_F(0x04000000) /* 0.250000000 */, + MAD_F(0x02d413cd) /* 0.176776695 */, + MAD_F(0x02000000) /* 0.125000000 */, + MAD_F(0x016a09e6) /* 0.088388348 */, + MAD_F(0x01000000) /* 0.062500000 */, + MAD_F(0x00b504f3) /* 0.044194174 */, + MAD_F(0x00800000) /* 0.031250000 */, + MAD_F(0x005a827a) /* 0.022097087 */, + MAD_F(0x00400000) /* 0.015625000 */, + MAD_F(0x002d413d) /* 0.011048543 */, + MAD_F(0x00200000) /* 0.007812500 */, + MAD_F(0x0016a09e) /* 0.005524272 */ + } +}; + +/* + * NAME: III_sideinfo() + * DESCRIPTION: decode frame side information from a bitstream + */ +static +enum mad_error III_sideinfo(struct mad_bitptr *ptr, unsigned int nch, + int lsf, struct sideinfo *si, + unsigned int *data_bitlen, + unsigned int *priv_bitlen) +{ + unsigned int ngr, gr, ch, i; + enum mad_error result = MAD_ERROR_NONE; + + *data_bitlen = 0; + *priv_bitlen = lsf ? ((nch == 1) ? 1 : 2) : ((nch == 1) ? 5 : 3); + + si->main_data_begin = mad_bit_read(ptr, lsf ? 8 : 9); + si->private_bits = mad_bit_read(ptr, *priv_bitlen); + + ngr = 1; + if (!lsf) { + ngr = 2; + + for (ch = 0; ch < nch; ++ch) + si->scfsi[ch] = mad_bit_read(ptr, 4); + } + + for (gr = 0; gr < ngr; ++gr) { + struct granule *granule = &si->gr[gr]; + + for (ch = 0; ch < nch; ++ch) { + struct channel *channel = &granule->ch[ch]; + + channel->part2_3_length = mad_bit_read(ptr, 12); + channel->big_values = mad_bit_read(ptr, 9); + channel->global_gain = mad_bit_read(ptr, 8); + channel->scalefac_compress = mad_bit_read(ptr, lsf ? 9 : 4); + + *data_bitlen += channel->part2_3_length; + + if (channel->big_values > 288 && result == 0) + result = MAD_ERROR_BADBIGVALUES; + + channel->flags = 0; + + /* window_switching_flag */ + if (mad_bit_read(ptr, 1)) { + channel->block_type = mad_bit_read(ptr, 2); + + if (channel->block_type == 0 && result == 0) + result = MAD_ERROR_BADBLOCKTYPE; + + if (!lsf && channel->block_type == 2 && si->scfsi[ch] && result == 0) + result = MAD_ERROR_BADSCFSI; + + channel->region0_count = 7; + channel->region1_count = 36; + + if (mad_bit_read(ptr, 1)) + channel->flags |= mixed_block_flag; + else if (channel->block_type == 2) + channel->region0_count = 8; + + for (i = 0; i < 2; ++i) + channel->table_select[i] = mad_bit_read(ptr, 5); + +# if defined(DEBUG) + channel->table_select[2] = 4; /* not used */ +# endif + + for (i = 0; i < 3; ++i) + channel->subblock_gain[i] = mad_bit_read(ptr, 3); + } + else { + channel->block_type = 0; + + for (i = 0; i < 3; ++i) + channel->table_select[i] = mad_bit_read(ptr, 5); + + channel->region0_count = mad_bit_read(ptr, 4); + channel->region1_count = mad_bit_read(ptr, 3); + } + + /* [preflag,] scalefac_scale, count1table_select */ + channel->flags |= mad_bit_read(ptr, lsf ? 2 : 3); + } + } + + return result; +} + +/* + * NAME: III_scalefactors_lsf() + * DESCRIPTION: decode channel scalefactors for LSF from a bitstream + */ +static +unsigned int III_scalefactors_lsf(struct mad_bitptr *ptr, + struct channel *channel, + struct channel *gr1ch, int mode_extension) +{ + struct mad_bitptr start; + unsigned int scalefac_compress, index, slen[4], part, n, i; + unsigned char const *nsfb; + + start = *ptr; + + scalefac_compress = channel->scalefac_compress; + index = (channel->block_type == 2) ? + ((channel->flags & mixed_block_flag) ? 2 : 1) : 0; + + if (!((mode_extension & I_STEREO) && gr1ch)) { + if (scalefac_compress < 400) { + slen[0] = (scalefac_compress >> 4) / 5; + slen[1] = (scalefac_compress >> 4) % 5; + slen[2] = (scalefac_compress % 16) >> 2; + slen[3] = scalefac_compress % 4; + + nsfb = nsfb_table[0][index]; + } + else if (scalefac_compress < 500) { + scalefac_compress -= 400; + + slen[0] = (scalefac_compress >> 2) / 5; + slen[1] = (scalefac_compress >> 2) % 5; + slen[2] = scalefac_compress % 4; + slen[3] = 0; + + nsfb = nsfb_table[1][index]; + } + else { + scalefac_compress -= 500; + + slen[0] = scalefac_compress / 3; + slen[1] = scalefac_compress % 3; + slen[2] = 0; + slen[3] = 0; + + channel->flags |= preflag; + + nsfb = nsfb_table[2][index]; + } + + n = 0; + for (part = 0; part < 4; ++part) { + for (i = 0; i < nsfb[part]; ++i) + channel->scalefac[n++] = mad_bit_read(ptr, slen[part]); + } + + while (n < 39) + channel->scalefac[n++] = 0; + } + else { /* (mode_extension & I_STEREO) && gr1ch (i.e. ch == 1) */ + scalefac_compress >>= 1; + + if (scalefac_compress < 180) { + slen[0] = scalefac_compress / 36; + slen[1] = (scalefac_compress % 36) / 6; + slen[2] = (scalefac_compress % 36) % 6; + slen[3] = 0; + + nsfb = nsfb_table[3][index]; + } + else if (scalefac_compress < 244) { + scalefac_compress -= 180; + + slen[0] = (scalefac_compress % 64) >> 4; + slen[1] = (scalefac_compress % 16) >> 2; + slen[2] = scalefac_compress % 4; + slen[3] = 0; + + nsfb = nsfb_table[4][index]; + } + else { + scalefac_compress -= 244; + + slen[0] = scalefac_compress / 3; + slen[1] = scalefac_compress % 3; + slen[2] = 0; + slen[3] = 0; + + nsfb = nsfb_table[5][index]; + } + + n = 0; + for (part = 0; part < 4; ++part) { + unsigned int max, is_pos; + + max = (1 << slen[part]) - 1; + + for (i = 0; i < nsfb[part]; ++i) { + is_pos = mad_bit_read(ptr, slen[part]); + + channel->scalefac[n] = is_pos; + gr1ch->scalefac[n++] = (is_pos == max); + } + } + + while (n < 39) { + channel->scalefac[n] = 0; + gr1ch->scalefac[n++] = 0; /* apparently not illegal */ + } + } + + return mad_bit_length(&start, ptr); +} + +/* + * NAME: III_scalefactors() + * DESCRIPTION: decode channel scalefactors of one granule from a bitstream + */ +static +unsigned int III_scalefactors(struct mad_bitptr *ptr, struct channel *channel, + struct channel const *gr0ch, unsigned int scfsi) +{ + struct mad_bitptr start; + unsigned int slen1, slen2, sfbi; + + start = *ptr; + + slen1 = sflen_table[channel->scalefac_compress].slen1; + slen2 = sflen_table[channel->scalefac_compress].slen2; + + if (channel->block_type == 2) { + unsigned int nsfb; + + sfbi = 0; + + nsfb = (channel->flags & mixed_block_flag) ? 8 + 3 * 3 : 6 * 3; + while (nsfb--) + channel->scalefac[sfbi++] = mad_bit_read(ptr, slen1); + + nsfb = 6 * 3; + while (nsfb--) + channel->scalefac[sfbi++] = mad_bit_read(ptr, slen2); + + nsfb = 1 * 3; + while (nsfb--) + channel->scalefac[sfbi++] = 0; + } + else { /* channel->block_type != 2 */ + if (scfsi & 0x8) { + for (sfbi = 0; sfbi < 6; ++sfbi) + channel->scalefac[sfbi] = gr0ch->scalefac[sfbi]; + } + else { + for (sfbi = 0; sfbi < 6; ++sfbi) + channel->scalefac[sfbi] = mad_bit_read(ptr, slen1); + } + + if (scfsi & 0x4) { + for (sfbi = 6; sfbi < 11; ++sfbi) + channel->scalefac[sfbi] = gr0ch->scalefac[sfbi]; + } + else { + for (sfbi = 6; sfbi < 11; ++sfbi) + channel->scalefac[sfbi] = mad_bit_read(ptr, slen1); + } + + if (scfsi & 0x2) { + for (sfbi = 11; sfbi < 16; ++sfbi) + channel->scalefac[sfbi] = gr0ch->scalefac[sfbi]; + } + else { + for (sfbi = 11; sfbi < 16; ++sfbi) + channel->scalefac[sfbi] = mad_bit_read(ptr, slen2); + } + + if (scfsi & 0x1) { + for (sfbi = 16; sfbi < 21; ++sfbi) + channel->scalefac[sfbi] = gr0ch->scalefac[sfbi]; + } + else { + for (sfbi = 16; sfbi < 21; ++sfbi) + channel->scalefac[sfbi] = mad_bit_read(ptr, slen2); + } + + channel->scalefac[21] = 0; + } + + return mad_bit_length(&start, ptr); +} + +/* + * The Layer III formula for requantization and scaling is defined by + * section 2.4.3.4.7.1 of ISO/IEC 11172-3, as follows: + * + * long blocks: + * xr[i] = sign(is[i]) * abs(is[i])^(4/3) * + * 2^((1/4) * (global_gain - 210)) * + * 2^-(scalefac_multiplier * + * (scalefac_l[sfb] + preflag * pretab[sfb])) + * + * short blocks: + * xr[i] = sign(is[i]) * abs(is[i])^(4/3) * + * 2^((1/4) * (global_gain - 210 - 8 * subblock_gain[w])) * + * 2^-(scalefac_multiplier * scalefac_s[sfb][w]) + * + * where: + * scalefac_multiplier = (scalefac_scale + 1) / 2 + * + * The routines III_exponents() and III_requantize() facilitate this + * calculation. + */ + +/* + * NAME: III_exponents() + * DESCRIPTION: calculate scalefactor exponents + */ +static +void III_exponents(struct channel const *channel, + unsigned char const *sfbwidth, signed int exponents[39]) +{ + signed int gain; + unsigned int scalefac_multiplier, sfbi; + + gain = (signed int) channel->global_gain - 210; + scalefac_multiplier = (channel->flags & scalefac_scale) ? 2 : 1; + + if (channel->block_type == 2) { + unsigned int l; + signed int gain0, gain1, gain2; + + sfbi = l = 0; + + if (channel->flags & mixed_block_flag) { + unsigned int premask; + + premask = (channel->flags & preflag) ? ~0 : 0; + + /* long block subbands 0-1 */ + + while (l < 36) { + exponents[sfbi] = gain - + (signed int) ((channel->scalefac[sfbi] + (pretab[sfbi] & premask)) << + scalefac_multiplier); + + l += sfbwidth[sfbi++]; + } + } + + /* this is probably wrong for 8000 Hz short/mixed blocks */ + + gain0 = gain - 8 * (signed int) channel->subblock_gain[0]; + gain1 = gain - 8 * (signed int) channel->subblock_gain[1]; + gain2 = gain - 8 * (signed int) channel->subblock_gain[2]; + + while (l < 576) { + exponents[sfbi + 0] = gain0 - + (signed int) (channel->scalefac[sfbi + 0] << scalefac_multiplier); + exponents[sfbi + 1] = gain1 - + (signed int) (channel->scalefac[sfbi + 1] << scalefac_multiplier); + exponents[sfbi + 2] = gain2 - + (signed int) (channel->scalefac[sfbi + 2] << scalefac_multiplier); + + l += 3 * sfbwidth[sfbi]; + sfbi += 3; + } + } + else { /* channel->block_type != 2 */ + if (channel->flags & preflag) { + for (sfbi = 0; sfbi < 22; ++sfbi) { + exponents[sfbi] = gain - + (signed int) ((channel->scalefac[sfbi] + pretab[sfbi]) << + scalefac_multiplier); + } + } + else { + for (sfbi = 0; sfbi < 22; ++sfbi) { + exponents[sfbi] = gain - + (signed int) (channel->scalefac[sfbi] << scalefac_multiplier); + } + } + } +} + +/* + * NAME: III_requantize() + * DESCRIPTION: requantize one (positive) value + */ +static +mad_fixed_t III_requantize(unsigned int value, signed int exp) +{ + mad_fixed_t requantized; + signed int frac; + struct fixedfloat const *power; + + frac = exp % 4; /* assumes sign(frac) == sign(exp) */ + exp /= 4; + + power = &rq_table[value]; + requantized = power->mantissa; + exp += power->exponent; + + if (exp < 0) { + if (-exp >= sizeof(mad_fixed_t) * CHAR_BIT) { + /* underflow */ + requantized = 0; + } + else { + requantized += 1L << (-exp - 1); + requantized >>= -exp; + } + } + else { + if (exp >= 5) { + /* overflow */ +# if defined(DEBUG) + fprintf(stderr, "requantize overflow (%f * 2^%d)\n", + mad_f_todouble(requantized), exp); +# endif + requantized = MAD_F_MAX; + } + else + requantized <<= exp; + } + + return frac ? mad_f_mul(requantized, root_table[3 + frac]) : requantized; +} + +/* we must take care that sz >= bits and sz < sizeof(long) lest bits == 0 */ +# define MASK(cache, sz, bits) \ + (((cache) >> ((sz) - (bits))) & ((1 << (bits)) - 1)) +# define MASK1BIT(cache, sz) \ + ((cache) & (1 << ((sz) - 1))) + +/* + * NAME: III_huffdecode() + * DESCRIPTION: decode Huffman code words of one channel of one granule + */ +static +enum mad_error III_huffdecode(struct mad_bitptr *ptr, mad_fixed_t xr[576], + struct channel *channel, + unsigned char const *sfbwidth, + unsigned int part2_length) +{ + signed int exponents[39], exp; + signed int const *expptr; + struct mad_bitptr peek; + signed int bits_left, cachesz; + register mad_fixed_t *xrptr; + mad_fixed_t const *sfbound; + register unsigned long bitcache; + + bits_left = (signed) channel->part2_3_length - (signed) part2_length; + if (bits_left < 0) + return MAD_ERROR_BADPART3LEN; + + III_exponents(channel, sfbwidth, exponents); + + peek = *ptr; + mad_bit_skip(ptr, bits_left); + + /* align bit reads to byte boundaries */ + cachesz = mad_bit_bitsleft(&peek); + cachesz += ((32 - 1 - 24) + (24 - cachesz)) & ~7; + + bitcache = mad_bit_read(&peek, cachesz); + bits_left -= cachesz; + + xrptr = &xr[0]; + + /* big_values */ + { + unsigned int region, rcount; + struct hufftable const *entry; + union huffpair const *table; + unsigned int linbits, startbits, big_values, reqhits; + mad_fixed_t reqcache[16]; + + sfbound = xrptr + *sfbwidth++; + rcount = channel->region0_count + 1; + + entry = &mad_huff_pair_table[channel->table_select[region = 0]]; + table = entry->table; + linbits = entry->linbits; + startbits = entry->startbits; + + if (table == 0) + return MAD_ERROR_BADHUFFTABLE; + + expptr = &exponents[0]; + exp = *expptr++; + reqhits = 0; + + big_values = channel->big_values; + + while (big_values-- && cachesz + bits_left > 0) { + union huffpair const *pair; + unsigned int clumpsz, value; + register mad_fixed_t requantized; + + if (xrptr == sfbound) { + sfbound += *sfbwidth++; + + /* change table if region boundary */ + + if (--rcount == 0) { + if (region == 0) + rcount = channel->region1_count + 1; + else + rcount = 0; /* all remaining */ + + entry = &mad_huff_pair_table[channel->table_select[++region]]; + table = entry->table; + linbits = entry->linbits; + startbits = entry->startbits; + + if (table == 0) + return MAD_ERROR_BADHUFFTABLE; + } + + if (exp != *expptr) { + exp = *expptr; + reqhits = 0; + } + + ++expptr; + } + + if (cachesz < 21) { + unsigned int bits; + + bits = ((32 - 1 - 21) + (21 - cachesz)) & ~7; + bitcache = (bitcache << bits) | mad_bit_read(&peek, bits); + cachesz += bits; + bits_left -= bits; + } + + /* hcod (0..19) */ + + clumpsz = startbits; + pair = &table[MASK(bitcache, cachesz, clumpsz)]; + + while (!pair->final) { + cachesz -= clumpsz; + + clumpsz = pair->ptr.bits; + pair = &table[pair->ptr.offset + MASK(bitcache, cachesz, clumpsz)]; + } + + cachesz -= pair->value.hlen; + + if (linbits) { + /* x (0..14) */ + + value = pair->value.x; + + switch (value) { + case 0: + xrptr[0] = 0; + break; + + case 15: + if (cachesz < linbits + 2) { + bitcache = (bitcache << 16) | mad_bit_read(&peek, 16); + cachesz += 16; + bits_left -= 16; + } + + value += MASK(bitcache, cachesz, linbits); + cachesz -= linbits; + + requantized = III_requantize(value, exp); + goto x_final; + + default: + if (reqhits & (1 << value)) + requantized = reqcache[value]; + else { + reqhits |= (1 << value); + requantized = reqcache[value] = III_requantize(value, exp); + } + + x_final: + xrptr[0] = MASK1BIT(bitcache, cachesz--) ? + -requantized : requantized; + } + + /* y (0..14) */ + + value = pair->value.y; + + switch (value) { + case 0: + xrptr[1] = 0; + break; + + case 15: + if (cachesz < linbits + 1) { + bitcache = (bitcache << 16) | mad_bit_read(&peek, 16); + cachesz += 16; + bits_left -= 16; + } + + value += MASK(bitcache, cachesz, linbits); + cachesz -= linbits; + + requantized = III_requantize(value, exp); + goto y_final; + + default: + if (reqhits & (1 << value)) + requantized = reqcache[value]; + else { + reqhits |= (1 << value); + requantized = reqcache[value] = III_requantize(value, exp); + } + + y_final: + xrptr[1] = MASK1BIT(bitcache, cachesz--) ? + -requantized : requantized; + } + } + else { + /* x (0..1) */ + + value = pair->value.x; + + if (value == 0) + xrptr[0] = 0; + else { + if (reqhits & (1 << value)) + requantized = reqcache[value]; + else { + reqhits |= (1 << value); + requantized = reqcache[value] = III_requantize(value, exp); + } + + xrptr[0] = MASK1BIT(bitcache, cachesz--) ? + -requantized : requantized; + } + + /* y (0..1) */ + + value = pair->value.y; + + if (value == 0) + xrptr[1] = 0; + else { + if (reqhits & (1 << value)) + requantized = reqcache[value]; + else { + reqhits |= (1 << value); + requantized = reqcache[value] = III_requantize(value, exp); + } + + xrptr[1] = MASK1BIT(bitcache, cachesz--) ? + -requantized : requantized; + } + } + + xrptr += 2; + } + } + + if (cachesz + bits_left < 0) + return MAD_ERROR_BADHUFFDATA; /* big_values overrun */ + + /* count1 */ + { + union huffquad const *table; + register mad_fixed_t requantized; + + table = mad_huff_quad_table[channel->flags & count1table_select]; + + requantized = III_requantize(1, exp); + + while (cachesz + bits_left > 0 && xrptr <= &xr[572]) { + union huffquad const *quad; + + /* hcod (1..6) */ + + if (cachesz < 10) { + bitcache = (bitcache << 16) | mad_bit_read(&peek, 16); + cachesz += 16; + bits_left -= 16; + } + + quad = &table[MASK(bitcache, cachesz, 4)]; + + /* quad tables guaranteed to have at most one extra lookup */ + if (!quad->final) { + cachesz -= 4; + + quad = &table[quad->ptr.offset + + MASK(bitcache, cachesz, quad->ptr.bits)]; + } + + cachesz -= quad->value.hlen; + + if (xrptr == sfbound) { + sfbound += *sfbwidth++; + + if (exp != *expptr) { + exp = *expptr; + requantized = III_requantize(1, exp); + } + + ++expptr; + } + + /* v (0..1) */ + + xrptr[0] = quad->value.v ? + (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0; + + /* w (0..1) */ + + xrptr[1] = quad->value.w ? + (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0; + + xrptr += 2; + + if (xrptr == sfbound) { + sfbound += *sfbwidth++; + + if (exp != *expptr) { + exp = *expptr; + requantized = III_requantize(1, exp); + } + + ++expptr; + } + + /* x (0..1) */ + + xrptr[0] = quad->value.x ? + (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0; + + /* y (0..1) */ + + xrptr[1] = quad->value.y ? + (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0; + + xrptr += 2; + } + + if (cachesz + bits_left < 0) { +# if 0 && defined(DEBUG) + fprintf(stderr, "huffman count1 overrun (%d bits)\n", + -(cachesz + bits_left)); +# endif + + /* technically the bitstream is misformatted, but apparently + some encoders are just a bit sloppy with stuffing bits */ + + xrptr -= 4; + } + } + + assert(-bits_left <= MAD_BUFFER_GUARD * CHAR_BIT); + +# if 0 && defined(DEBUG) + if (bits_left < 0) + fprintf(stderr, "read %d bits too many\n", -bits_left); + else if (cachesz + bits_left > 0) + fprintf(stderr, "%d stuffing bits\n", cachesz + bits_left); +# endif + + /* rzero */ + while (xrptr < &xr[576]) { + xrptr[0] = 0; + xrptr[1] = 0; + + xrptr += 2; + } + + return MAD_ERROR_NONE; +} + +# undef MASK +# undef MASK1BIT + +/* + * NAME: III_reorder() + * DESCRIPTION: reorder frequency lines of a short block into subband order + */ +static +void III_reorder(mad_fixed_t xr[576], struct channel const *channel, + unsigned char const sfbwidth[39]) +{ + mad_fixed_t tmp[32][3][6]; + unsigned int sb, l, f, w, sbw[3], sw[3]; + + /* this is probably wrong for 8000 Hz mixed blocks */ + + sb = 0; + if (channel->flags & mixed_block_flag) { + sb = 2; + + l = 0; + while (l < 36) + l += *sfbwidth++; + } + + for (w = 0; w < 3; ++w) { + sbw[w] = sb; + sw[w] = 0; + } + + f = *sfbwidth++; + w = 0; + + for (l = 18 * sb; l < 576; ++l) { + if (f-- == 0) { + f = *sfbwidth++ - 1; + w = (w + 1) % 3; + } + + tmp[sbw[w]][w][sw[w]++] = xr[l]; + + if (sw[w] == 6) { + sw[w] = 0; + ++sbw[w]; + } + } + + memcpy(&xr[18 * sb], &tmp[sb], (576 - 18 * sb) * sizeof(mad_fixed_t)); +} + +/* + * NAME: III_stereo() + * DESCRIPTION: perform joint stereo processing on a granule + */ +static +enum mad_error III_stereo(mad_fixed_t xr[2][576], + struct granule const *granule, + struct mad_header *header, + unsigned char const *sfbwidth) +{ + short modes[39]; + unsigned int sfbi, l, n, i; + + if (granule->ch[0].block_type != + granule->ch[1].block_type || + (granule->ch[0].flags & mixed_block_flag) != + (granule->ch[1].flags & mixed_block_flag)) + return MAD_ERROR_BADSTEREO; + + for (i = 0; i < 39; ++i) + modes[i] = header->mode_extension; + + /* intensity stereo */ + + if (header->mode_extension & I_STEREO) { + struct channel const *right_ch = &granule->ch[1]; + mad_fixed_t const *right_xr = xr[1]; + unsigned int is_pos; + + header->flags |= MAD_FLAG_I_STEREO; + + /* first determine which scalefactor bands are to be processed */ + + if (right_ch->block_type == 2) { + unsigned int lower, start, max, bound[3], w; + + lower = start = max = bound[0] = bound[1] = bound[2] = 0; + + sfbi = l = 0; + + if (right_ch->flags & mixed_block_flag) { + while (l < 36) { + n = sfbwidth[sfbi++]; + + for (i = 0; i < n; ++i) { + if (right_xr[i]) { + lower = sfbi; + break; + } + } + + right_xr += n; + l += n; + } + + start = sfbi; + } + + w = 0; + while (l < 576) { + n = sfbwidth[sfbi++]; + + for (i = 0; i < n; ++i) { + if (right_xr[i]) { + max = bound[w] = sfbi; + break; + } + } + + right_xr += n; + l += n; + w = (w + 1) % 3; + } + + if (max) + lower = start; + + /* long blocks */ + + for (i = 0; i < lower; ++i) + modes[i] = header->mode_extension & ~I_STEREO; + + /* short blocks */ + + w = 0; + for (i = start; i < max; ++i) { + if (i < bound[w]) + modes[i] = header->mode_extension & ~I_STEREO; + + w = (w + 1) % 3; + } + } + else { /* right_ch->block_type != 2 */ + unsigned int bound; + + bound = 0; + for (sfbi = l = 0; l < 576; l += n) { + n = sfbwidth[sfbi++]; + + for (i = 0; i < n; ++i) { + if (right_xr[i]) { + bound = sfbi; + break; + } + } + + right_xr += n; + } + + for (i = 0; i < bound; ++i) + modes[i] = header->mode_extension & ~I_STEREO; + } + + /* now do the actual processing */ + + if (header->flags & MAD_FLAG_LSF_EXT) { + unsigned char const *illegal_pos = granule[1].ch[1].scalefac; + mad_fixed_t const *lsf_scale; + + /* intensity_scale */ + lsf_scale = is_lsf_table[right_ch->scalefac_compress & 0x1]; + + for (sfbi = l = 0; l < 576; ++sfbi, l += n) { + n = sfbwidth[sfbi]; + + if (!(modes[sfbi] & I_STEREO)) + continue; + + if (illegal_pos[sfbi]) { + modes[sfbi] &= ~I_STEREO; + continue; + } + + is_pos = right_ch->scalefac[sfbi]; + + for (i = 0; i < n; ++i) { + register mad_fixed_t left; + + left = xr[0][l + i]; + + if (is_pos == 0) + xr[1][l + i] = left; + else { + register mad_fixed_t opposite; + + opposite = mad_f_mul(left, lsf_scale[(is_pos - 1) / 2]); + + if (is_pos & 1) { + xr[0][l + i] = opposite; + xr[1][l + i] = left; + } + else + xr[1][l + i] = opposite; + } + } + } + } + else { /* !(header->flags & MAD_FLAG_LSF_EXT) */ + for (sfbi = l = 0; l < 576; ++sfbi, l += n) { + n = sfbwidth[sfbi]; + + if (!(modes[sfbi] & I_STEREO)) + continue; + + is_pos = right_ch->scalefac[sfbi]; + + if (is_pos >= 7) { /* illegal intensity position */ + modes[sfbi] &= ~I_STEREO; + continue; + } + + for (i = 0; i < n; ++i) { + register mad_fixed_t left; + + left = xr[0][l + i]; + + xr[0][l + i] = mad_f_mul(left, is_table[ is_pos]); + xr[1][l + i] = mad_f_mul(left, is_table[6 - is_pos]); + } + } + } + } + + /* middle/side stereo */ + + if (header->mode_extension & MS_STEREO) { + register mad_fixed_t invsqrt2; + + header->flags |= MAD_FLAG_MS_STEREO; + + invsqrt2 = root_table[3 + -2]; + + for (sfbi = l = 0; l < 576; ++sfbi, l += n) { + n = sfbwidth[sfbi]; + + if (modes[sfbi] != MS_STEREO) + continue; + + for (i = 0; i < n; ++i) { + register mad_fixed_t m, s; + + m = xr[0][l + i]; + s = xr[1][l + i]; + + xr[0][l + i] = mad_f_mul(m + s, invsqrt2); /* l = (m + s) / sqrt(2) */ + xr[1][l + i] = mad_f_mul(m - s, invsqrt2); /* r = (m - s) / sqrt(2) */ + } + } + } + + return MAD_ERROR_NONE; +} + +/* + * NAME: III_aliasreduce() + * DESCRIPTION: perform frequency line alias reduction + */ +static +void III_aliasreduce(mad_fixed_t xr[576], int lines) +{ + mad_fixed_t const *bound; + int i; + + bound = &xr[lines]; + for (xr += 18; xr < bound; xr += 18) { + for (i = 0; i < 8; ++i) { + register mad_fixed_t a, b; + register mad_fixed64hi_t hi; + register mad_fixed64lo_t lo; + + a = xr[-1 - i]; + b = xr[ i]; + +# if defined(ASO_ZEROCHECK) + if (a | b) { +# endif + MAD_F_ML0(hi, lo, a, cs[i]); + MAD_F_MLA(hi, lo, -b, ca[i]); + + xr[-1 - i] = MAD_F_MLZ(hi, lo); + + MAD_F_ML0(hi, lo, b, cs[i]); + MAD_F_MLA(hi, lo, a, ca[i]); + + xr[ i] = MAD_F_MLZ(hi, lo); +# if defined(ASO_ZEROCHECK) + } +# endif + } + } +} + +# if defined(ASO_IMDCT) +void III_imdct_l(mad_fixed_t const [18], mad_fixed_t [36], unsigned int); +# else +/* + * NAME: imdct36 + * DESCRIPTION: perform X[18]->x[36] IMDCT + */ +static inline +void imdct36(mad_fixed_t const X[18], mad_fixed_t x[36]) +{ + mad_fixed_t t0, t1, t2, t3, t4, t5, t6, t7; + mad_fixed_t t8, t9, t10, t11, t12, t13, t14, t15; + register mad_fixed64hi_t hi; + register mad_fixed64lo_t lo; + + MAD_F_ML0(hi, lo, X[4], MAD_F(0x0ec835e8)); + MAD_F_MLA(hi, lo, X[13], MAD_F(0x061f78aa)); + + t6 = MAD_F_MLZ(hi, lo); + + MAD_F_MLA(hi, lo, (t14 = X[1] - X[10]), -MAD_F(0x061f78aa)); + MAD_F_MLA(hi, lo, (t15 = X[7] + X[16]), -MAD_F(0x0ec835e8)); + + t0 = MAD_F_MLZ(hi, lo); + + MAD_F_MLA(hi, lo, (t8 = X[0] - X[11] - X[12]), MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, (t9 = X[2] - X[9] - X[14]), MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, (t10 = X[3] - X[8] - X[15]), -MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, (t11 = X[5] - X[6] - X[17]), -MAD_F(0x0fdcf549)); + + x[7] = MAD_F_MLZ(hi, lo); + x[10] = -x[7]; + + MAD_F_ML0(hi, lo, t8, -MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, t9, MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, t10, MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, t11, -MAD_F(0x09bd7ca0)); + + x[19] = x[34] = MAD_F_MLZ(hi, lo) - t0; + + t12 = X[0] - X[3] + X[8] - X[11] - X[12] + X[15]; + t13 = X[2] + X[5] - X[6] - X[9] - X[14] - X[17]; + + MAD_F_ML0(hi, lo, t12, -MAD_F(0x0ec835e8)); + MAD_F_MLA(hi, lo, t13, MAD_F(0x061f78aa)); + + x[22] = x[31] = MAD_F_MLZ(hi, lo) + t0; + + MAD_F_ML0(hi, lo, X[1], -MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, X[7], MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, X[10], -MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, X[16], MAD_F(0x0cb19346)); + + t1 = MAD_F_MLZ(hi, lo) + t6; + + MAD_F_ML0(hi, lo, X[0], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[11], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0f9ee890)); + + x[6] = MAD_F_MLZ(hi, lo) + t1; + x[11] = -x[6]; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[2], -MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[17], MAD_F(0x04cfb0e2)); + + x[23] = x[30] = MAD_F_MLZ(hi, lo) + t1; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[11], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0acf37ad)); + + x[18] = x[35] = MAD_F_MLZ(hi, lo) - t1; + + MAD_F_ML0(hi, lo, X[4], MAD_F(0x061f78aa)); + MAD_F_MLA(hi, lo, X[13], -MAD_F(0x0ec835e8)); + + t7 = MAD_F_MLZ(hi, lo); + + MAD_F_MLA(hi, lo, X[1], -MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, X[7], MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, X[10], MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, X[16], -MAD_F(0x09bd7ca0)); + + t2 = MAD_F_MLZ(hi, lo); + + MAD_F_MLA(hi, lo, X[0], MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[12], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[17], MAD_F(0x0f426cb5)); + + x[5] = MAD_F_MLZ(hi, lo); + x[12] = -x[5]; + + MAD_F_ML0(hi, lo, X[0], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[2], -MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[11], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0bcbe352)); + + x[0] = MAD_F_MLZ(hi, lo) + t2; + x[17] = -x[0]; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[2], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x03768962)); + + x[24] = x[29] = MAD_F_MLZ(hi, lo) + t2; + + MAD_F_ML0(hi, lo, X[1], -MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, X[7], -MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, X[10], MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, X[16], MAD_F(0x0fdcf549)); + + t3 = MAD_F_MLZ(hi, lo) + t7; + + MAD_F_ML0(hi, lo, X[0], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[12], MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0ffc19fd)); + + x[8] = MAD_F_MLZ(hi, lo) + t3; + x[9] = -x[8]; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[14], -MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[17], MAD_F(0x07635284)); + + x[21] = x[32] = MAD_F_MLZ(hi, lo) + t3; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[12], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0898c779)); + + x[20] = x[33] = MAD_F_MLZ(hi, lo) - t3; + + MAD_F_ML0(hi, lo, t14, -MAD_F(0x0ec835e8)); + MAD_F_MLA(hi, lo, t15, MAD_F(0x061f78aa)); + + t4 = MAD_F_MLZ(hi, lo) - t7; + + MAD_F_ML0(hi, lo, t12, MAD_F(0x061f78aa)); + MAD_F_MLA(hi, lo, t13, MAD_F(0x0ec835e8)); + + x[4] = MAD_F_MLZ(hi, lo) + t4; + x[13] = -x[4]; + + MAD_F_ML0(hi, lo, t8, MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, t9, -MAD_F(0x0216a2a2)); + MAD_F_MLA(hi, lo, t10, MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, t11, -MAD_F(0x0cb19346)); + + x[1] = MAD_F_MLZ(hi, lo) + t4; + x[16] = -x[1]; + + MAD_F_ML0(hi, lo, t8, -MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, t9, -MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, t10, -MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, t11, -MAD_F(0x0216a2a2)); + + x[25] = x[28] = MAD_F_MLZ(hi, lo) + t4; + + MAD_F_ML0(hi, lo, X[1], -MAD_F(0x0fdcf549)); + MAD_F_MLA(hi, lo, X[7], -MAD_F(0x0cb19346)); + MAD_F_MLA(hi, lo, X[10], -MAD_F(0x09bd7ca0)); + MAD_F_MLA(hi, lo, X[16], -MAD_F(0x0216a2a2)); + + t5 = MAD_F_MLZ(hi, lo) - t6; + + MAD_F_ML0(hi, lo, X[0], MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[6], MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[9], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[12], MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[15], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0d7e8807)); + + x[2] = MAD_F_MLZ(hi, lo) + t5; + x[15] = -x[2]; + + MAD_F_ML0(hi, lo, X[0], MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[2], MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[3], MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[5], MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x00b2aa3e)); + MAD_F_MLA(hi, lo, X[8], MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[11], MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[14], MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[17], MAD_F(0x0e313245)); + + x[3] = MAD_F_MLZ(hi, lo) + t5; + x[14] = -x[3]; + + MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0ffc19fd)); + MAD_F_MLA(hi, lo, X[2], -MAD_F(0x0f9ee890)); + MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0f426cb5)); + MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0e313245)); + MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0d7e8807)); + MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0bcbe352)); + MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0acf37ad)); + MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0898c779)); + MAD_F_MLA(hi, lo, X[12], -MAD_F(0x07635284)); + MAD_F_MLA(hi, lo, X[14], -MAD_F(0x04cfb0e2)); + MAD_F_MLA(hi, lo, X[15], -MAD_F(0x03768962)); + MAD_F_MLA(hi, lo, X[17], -MAD_F(0x00b2aa3e)); + + x[26] = x[27] = MAD_F_MLZ(hi, lo) + t5; +} + +/* + * NAME: III_imdct_l() + * DESCRIPTION: perform IMDCT and windowing for long blocks + */ +static +void III_imdct_l(mad_fixed_t const X[18], mad_fixed_t z[36], + unsigned int block_type) +{ + unsigned int i; + + /* IMDCT */ + + imdct36(X, z); + + /* windowing */ + + switch (block_type) { + case 0: /* normal window */ +# if defined(ASO_INTERLEAVE1) + { + register mad_fixed_t tmp1, tmp2; + + tmp1 = window_l[0]; + tmp2 = window_l[1]; + + for (i = 0; i < 34; i += 2) { + z[i + 0] = mad_f_mul(z[i + 0], tmp1); + tmp1 = window_l[i + 2]; + z[i + 1] = mad_f_mul(z[i + 1], tmp2); + tmp2 = window_l[i + 3]; + } + + z[34] = mad_f_mul(z[34], tmp1); + z[35] = mad_f_mul(z[35], tmp2); + } +# elif defined(ASO_INTERLEAVE2) + { + register mad_fixed_t tmp1, tmp2; + + tmp1 = z[0]; + tmp2 = window_l[0]; + + for (i = 0; i < 35; ++i) { + z[i] = mad_f_mul(tmp1, tmp2); + tmp1 = z[i + 1]; + tmp2 = window_l[i + 1]; + } + + z[35] = mad_f_mul(tmp1, tmp2); + } +# elif 1 + for (i = 0; i < 36; i += 4) { + z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]); + z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]); + z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]); + z[i + 3] = mad_f_mul(z[i + 3], window_l[i + 3]); + } +# else + for (i = 0; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]); +# endif + break; + + case 1: /* start block */ + for (i = 0; i < 18; ++i) z[i] = mad_f_mul(z[i], window_l[i]); + /* (i = 18; i < 24; ++i) z[i] unchanged */ + for (i = 24; i < 30; ++i) z[i] = mad_f_mul(z[i], window_s[i - 18]); + for (i = 30; i < 36; ++i) z[i] = 0; + break; + + case 3: /* stop block */ + for (i = 0; i < 6; ++i) z[i] = 0; + for (i = 6; i < 12; ++i) z[i] = mad_f_mul(z[i], window_s[i - 6]); + /* (i = 12; i < 18; ++i) z[i] unchanged */ + for (i = 18; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]); + break; + } +} +# endif /* ASO_IMDCT */ + +/* + * NAME: III_imdct_s() + * DESCRIPTION: perform IMDCT and windowing for short blocks + */ +static +void III_imdct_s(mad_fixed_t const X[18], mad_fixed_t z[36]) +{ + mad_fixed_t y[36], *yptr; + mad_fixed_t const *wptr; + int w, i; + register mad_fixed64hi_t hi; + register mad_fixed64lo_t lo; + + /* IMDCT */ + + yptr = &y[0]; + + for (w = 0; w < 3; ++w) { + register mad_fixed_t const (*s)[6]; + + s = imdct_s; + + for (i = 0; i < 3; ++i) { + MAD_F_ML0(hi, lo, X[0], (*s)[0]); + MAD_F_MLA(hi, lo, X[1], (*s)[1]); + MAD_F_MLA(hi, lo, X[2], (*s)[2]); + MAD_F_MLA(hi, lo, X[3], (*s)[3]); + MAD_F_MLA(hi, lo, X[4], (*s)[4]); + MAD_F_MLA(hi, lo, X[5], (*s)[5]); + + yptr[i + 0] = MAD_F_MLZ(hi, lo); + yptr[5 - i] = -yptr[i + 0]; + + ++s; + + MAD_F_ML0(hi, lo, X[0], (*s)[0]); + MAD_F_MLA(hi, lo, X[1], (*s)[1]); + MAD_F_MLA(hi, lo, X[2], (*s)[2]); + MAD_F_MLA(hi, lo, X[3], (*s)[3]); + MAD_F_MLA(hi, lo, X[4], (*s)[4]); + MAD_F_MLA(hi, lo, X[5], (*s)[5]); + + yptr[ i + 6] = MAD_F_MLZ(hi, lo); + yptr[11 - i] = yptr[i + 6]; + + ++s; + } + + yptr += 12; + X += 6; + } + + /* windowing, overlapping and concatenation */ + + yptr = &y[0]; + wptr = &window_s[0]; + + for (i = 0; i < 6; ++i) { + z[i + 0] = 0; + z[i + 6] = mad_f_mul(yptr[ 0 + 0], wptr[0]); + + MAD_F_ML0(hi, lo, yptr[ 0 + 6], wptr[6]); + MAD_F_MLA(hi, lo, yptr[12 + 0], wptr[0]); + + z[i + 12] = MAD_F_MLZ(hi, lo); + + MAD_F_ML0(hi, lo, yptr[12 + 6], wptr[6]); + MAD_F_MLA(hi, lo, yptr[24 + 0], wptr[0]); + + z[i + 18] = MAD_F_MLZ(hi, lo); + + z[i + 24] = mad_f_mul(yptr[24 + 6], wptr[6]); + z[i + 30] = 0; + + ++yptr; + ++wptr; + } +} + +/* + * NAME: III_overlap() + * DESCRIPTION: perform overlap-add of windowed IMDCT outputs + */ +static +void III_overlap(mad_fixed_t const output[36], mad_fixed_t overlap[18], + mad_fixed_t sample[18][32], unsigned int sb) +{ + unsigned int i; + +# if defined(ASO_INTERLEAVE2) + { + register mad_fixed_t tmp1, tmp2; + + tmp1 = overlap[0]; + tmp2 = overlap[1]; + + for (i = 0; i < 16; i += 2) { + sample[i + 0][sb] = output[i + 0 + 0] + tmp1; + overlap[i + 0] = output[i + 0 + 18]; + tmp1 = overlap[i + 2]; + + sample[i + 1][sb] = output[i + 1 + 0] + tmp2; + overlap[i + 1] = output[i + 1 + 18]; + tmp2 = overlap[i + 3]; + } + + sample[16][sb] = output[16 + 0] + tmp1; + overlap[16] = output[16 + 18]; + sample[17][sb] = output[17 + 0] + tmp2; + overlap[17] = output[17 + 18]; + } +# elif 0 + for (i = 0; i < 18; i += 2) { + sample[i + 0][sb] = output[i + 0 + 0] + overlap[i + 0]; + overlap[i + 0] = output[i + 0 + 18]; + + sample[i + 1][sb] = output[i + 1 + 0] + overlap[i + 1]; + overlap[i + 1] = output[i + 1 + 18]; + } +# else + for (i = 0; i < 18; ++i) { + sample[i][sb] = output[i + 0] + overlap[i]; + overlap[i] = output[i + 18]; + } +# endif +} + +/* + * NAME: III_overlap_z() + * DESCRIPTION: perform "overlap-add" of zero IMDCT outputs + */ +static inline +void III_overlap_z(mad_fixed_t overlap[18], + mad_fixed_t sample[18][32], unsigned int sb) +{ + unsigned int i; + +# if defined(ASO_INTERLEAVE2) + { + register mad_fixed_t tmp1, tmp2; + + tmp1 = overlap[0]; + tmp2 = overlap[1]; + + for (i = 0; i < 16; i += 2) { + sample[i + 0][sb] = tmp1; + overlap[i + 0] = 0; + tmp1 = overlap[i + 2]; + + sample[i + 1][sb] = tmp2; + overlap[i + 1] = 0; + tmp2 = overlap[i + 3]; + } + + sample[16][sb] = tmp1; + overlap[16] = 0; + sample[17][sb] = tmp2; + overlap[17] = 0; + } +# else + for (i = 0; i < 18; ++i) { + sample[i][sb] = overlap[i]; + overlap[i] = 0; + } +# endif +} + +/* + * NAME: III_freqinver() + * DESCRIPTION: perform subband frequency inversion for odd sample lines + */ +static +void III_freqinver(mad_fixed_t sample[18][32], unsigned int sb) +{ + unsigned int i; + +# if 1 || defined(ASO_INTERLEAVE1) || defined(ASO_INTERLEAVE2) + { + register mad_fixed_t tmp1, tmp2; + + tmp1 = sample[1][sb]; + tmp2 = sample[3][sb]; + + for (i = 1; i < 13; i += 4) { + sample[i + 0][sb] = -tmp1; + tmp1 = sample[i + 4][sb]; + sample[i + 2][sb] = -tmp2; + tmp2 = sample[i + 6][sb]; + } + + sample[13][sb] = -tmp1; + tmp1 = sample[17][sb]; + sample[15][sb] = -tmp2; + sample[17][sb] = -tmp1; + } +# else + for (i = 1; i < 18; i += 2) + sample[i][sb] = -sample[i][sb]; +# endif +} + +/* + * NAME: III_decode() + * DESCRIPTION: decode frame main_data + */ +static +enum mad_error III_decode(struct mad_bitptr *ptr, struct mad_frame *frame, + struct sideinfo *si, unsigned int nch) +{ + struct mad_header *header = &frame->header; + unsigned int sfreqi, ngr, gr; + + { + unsigned int sfreq; + + sfreq = header->samplerate; + if (header->flags & MAD_FLAG_MPEG_2_5_EXT) + sfreq *= 2; + + /* 48000 => 0, 44100 => 1, 32000 => 2, + 24000 => 3, 22050 => 4, 16000 => 5 */ + sfreqi = ((sfreq >> 7) & 0x000f) + + ((sfreq >> 15) & 0x0001) - 8; + + if (header->flags & MAD_FLAG_MPEG_2_5_EXT) + sfreqi += 3; + } + + /* scalefactors, Huffman decoding, requantization */ + + ngr = (header->flags & MAD_FLAG_LSF_EXT) ? 1 : 2; + + for (gr = 0; gr < ngr; ++gr) { + struct granule *granule = &si->gr[gr]; + unsigned char const *sfbwidth[2]; + mad_fixed_t xr[2][576]; + unsigned int ch; + enum mad_error error; + + for (ch = 0; ch < nch; ++ch) { + struct channel *channel = &granule->ch[ch]; + unsigned int part2_length; + + sfbwidth[ch] = sfbwidth_table[sfreqi].l; + if (channel->block_type == 2) { + sfbwidth[ch] = (channel->flags & mixed_block_flag) ? + sfbwidth_table[sfreqi].m : sfbwidth_table[sfreqi].s; + } + + if (header->flags & MAD_FLAG_LSF_EXT) { + part2_length = III_scalefactors_lsf(ptr, channel, + ch == 0 ? 0 : &si->gr[1].ch[1], + header->mode_extension); + } + else { + part2_length = III_scalefactors(ptr, channel, &si->gr[0].ch[ch], + gr == 0 ? 0 : si->scfsi[ch]); + } + + error = III_huffdecode(ptr, xr[ch], channel, sfbwidth[ch], part2_length); + if (error) + return error; + } + + /* joint stereo processing */ + + if (header->mode == MAD_MODE_JOINT_STEREO && header->mode_extension) { + error = III_stereo(xr, granule, header, sfbwidth[0]); + if (error) + return error; + } + + /* reordering, alias reduction, IMDCT, overlap-add, frequency inversion */ + + for (ch = 0; ch < nch; ++ch) { + struct channel const *channel = &granule->ch[ch]; + mad_fixed_t (*sample)[32] = &frame->sbsample[ch][18 * gr]; + unsigned int sb, l, i, sblimit; + mad_fixed_t output[36]; + + if (channel->block_type == 2) { + III_reorder(xr[ch], channel, sfbwidth[ch]); + +# if !defined(OPT_STRICT) + /* + * According to ISO/IEC 11172-3, "Alias reduction is not applied for + * granules with block_type == 2 (short block)." However, other + * sources suggest alias reduction should indeed be performed on the + * lower two subbands of mixed blocks. Most other implementations do + * this, so by default we will too. + */ + if (channel->flags & mixed_block_flag) + III_aliasreduce(xr[ch], 36); +# endif + } + else + III_aliasreduce(xr[ch], 576); + + l = 0; + + /* subbands 0-1 */ + + if (channel->block_type != 2 || (channel->flags & mixed_block_flag)) { + unsigned int block_type; + + block_type = channel->block_type; + if (channel->flags & mixed_block_flag) + block_type = 0; + + /* long blocks */ + for (sb = 0; sb < 2; ++sb, l += 18) { + III_imdct_l(&xr[ch][l], output, block_type); + III_overlap(output, (*frame->overlap)[ch][sb], sample, sb); + } + } + else { + /* short blocks */ + for (sb = 0; sb < 2; ++sb, l += 18) { + III_imdct_s(&xr[ch][l], output); + III_overlap(output, (*frame->overlap)[ch][sb], sample, sb); + } + } + + III_freqinver(sample, 1); + + /* (nonzero) subbands 2-31 */ + + i = 576; + while (i > 36 && xr[ch][i - 1] == 0) + --i; + + sblimit = 32 - (576 - i) / 18; + + if (channel->block_type != 2) { + /* long blocks */ + for (sb = 2; sb < sblimit; ++sb, l += 18) { + III_imdct_l(&xr[ch][l], output, channel->block_type); + III_overlap(output, (*frame->overlap)[ch][sb], sample, sb); + + if (sb & 1) + III_freqinver(sample, sb); + } + } + else { + /* short blocks */ + for (sb = 2; sb < sblimit; ++sb, l += 18) { + III_imdct_s(&xr[ch][l], output); + III_overlap(output, (*frame->overlap)[ch][sb], sample, sb); + + if (sb & 1) + III_freqinver(sample, sb); + } + } + + /* remaining (zero) subbands */ + + for (sb = sblimit; sb < 32; ++sb) { + III_overlap_z((*frame->overlap)[ch][sb], sample, sb); + + if (sb & 1) + III_freqinver(sample, sb); + } + } + } + + return MAD_ERROR_NONE; +} + +/* + * NAME: layer->III() + * DESCRIPTION: decode a single Layer III frame + */ +int mad_layer_III(struct mad_stream *stream, struct mad_frame *frame) +{ + struct mad_header *header = &frame->header; + unsigned int nch, priv_bitlen, next_md_begin = 0; + unsigned int si_len, data_bitlen, md_len; + unsigned int frame_space, frame_used, frame_free; + struct mad_bitptr ptr; + struct sideinfo si; + enum mad_error error; + int result = 0; + + /* allocate Layer III dynamic structures */ + + if (stream->main_data == 0) { + stream->main_data = malloc(MAD_BUFFER_MDLEN); + if (stream->main_data == 0) { + stream->error = MAD_ERROR_NOMEM; + return -1; + } + } + + if (frame->overlap == 0) { + frame->overlap = calloc(2 * 32 * 18, sizeof(mad_fixed_t)); + if (frame->overlap == 0) { + stream->error = MAD_ERROR_NOMEM; + return -1; + } + } + + nch = MAD_NCHANNELS(header); + si_len = (header->flags & MAD_FLAG_LSF_EXT) ? + (nch == 1 ? 9 : 17) : (nch == 1 ? 17 : 32); + + /* check frame sanity */ + + if (stream->next_frame - mad_bit_nextbyte(&stream->ptr) < + (signed int) si_len) { + stream->error = MAD_ERROR_BADFRAMELEN; + stream->md_len = 0; + return -1; + } + + /* check CRC word */ + + if (header->flags & MAD_FLAG_PROTECTION) { + header->crc_check = + mad_bit_crc(stream->ptr, si_len * CHAR_BIT, header->crc_check); + + if (header->crc_check != header->crc_target && + !(frame->options & MAD_OPTION_IGNORECRC)) { + stream->error = MAD_ERROR_BADCRC; + result = -1; + } + } + + /* decode frame side information */ + + error = III_sideinfo(&stream->ptr, nch, header->flags & MAD_FLAG_LSF_EXT, + &si, &data_bitlen, &priv_bitlen); + if (error && result == 0) { + stream->error = error; + result = -1; + } + + header->flags |= priv_bitlen; + header->private_bits |= si.private_bits; + + /* find main_data of next frame */ + + { + struct mad_bitptr peek; + unsigned long header; + + mad_bit_init(&peek, stream->next_frame); + + header = mad_bit_read(&peek, 32); + if ((header & 0xffe60000L) /* syncword | layer */ == 0xffe20000L) { + if (!(header & 0x00010000L)) /* protection_bit */ + mad_bit_skip(&peek, 16); /* crc_check */ + + next_md_begin = + mad_bit_read(&peek, (header & 0x00080000L) /* ID */ ? 9 : 8); + } + + mad_bit_finish(&peek); + } + + /* find main_data of this frame */ + + frame_space = stream->next_frame - mad_bit_nextbyte(&stream->ptr); + + if (next_md_begin > si.main_data_begin + frame_space) + next_md_begin = 0; + + md_len = si.main_data_begin + frame_space - next_md_begin; + + frame_used = 0; + + if (si.main_data_begin == 0) { + ptr = stream->ptr; + stream->md_len = 0; + + frame_used = md_len; + } + else { + if (si.main_data_begin > stream->md_len) { + if (result == 0) { + stream->error = MAD_ERROR_BADDATAPTR; + result = -1; + } + } + else { + mad_bit_init(&ptr, + *stream->main_data + stream->md_len - si.main_data_begin); + + if (md_len > si.main_data_begin) { + assert(stream->md_len + md_len - + si.main_data_begin <= MAD_BUFFER_MDLEN); + + memcpy(*stream->main_data + stream->md_len, + mad_bit_nextbyte(&stream->ptr), + frame_used = md_len - si.main_data_begin); + stream->md_len += frame_used; + } + } + } + + frame_free = frame_space - frame_used; + + /* decode main_data */ + + if (result == 0) { + error = III_decode(&ptr, frame, &si, nch); + if (error) { + stream->error = error; + result = -1; + } + + /* designate ancillary bits */ + + stream->anc_ptr = ptr; + stream->anc_bitlen = md_len * CHAR_BIT - data_bitlen; + } + +# if 0 && defined(DEBUG) + fprintf(stderr, + "main_data_begin:%u, md_len:%u, frame_free:%u, " + "data_bitlen:%u, anc_bitlen: %u\n", + si.main_data_begin, md_len, frame_free, + data_bitlen, stream->anc_bitlen); +# endif + + /* preload main_data buffer with up to 511 bytes for next frame(s) */ + + if (frame_free >= next_md_begin) { + memcpy(*stream->main_data, + stream->next_frame - next_md_begin, next_md_begin); + stream->md_len = next_md_begin; + } + else { + if (md_len < si.main_data_begin) { + unsigned int extra; + + extra = si.main_data_begin - md_len; + if (extra + frame_free > next_md_begin) + extra = next_md_begin - frame_free; + + if (extra < stream->md_len) { + memmove(*stream->main_data, + *stream->main_data + stream->md_len - extra, extra); + stream->md_len = extra; + } + } + else + stream->md_len = 0; + + memcpy(*stream->main_data + stream->md_len, + stream->next_frame - frame_free, frame_free); + stream->md_len += frame_free; + } + + return result; +} |