/*____________________________________________________________________________ FreeAmp - The Free MP3 Player MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology Corp. http://www.xingtech.com Portions Copyright (C) 1998-1999 EMusic.com 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., 675 Mass Ave, Cambridge, MA 02139, USA. $Id$ ____________________________________________________________________________*/ /**** cup.c *************************************************** MPEG audio decoder Layer I/II mpeg1 and mpeg2 should be portable ANSI C, should be endian independent mod 2/21/95 2/21/95 add bit skip, sb limiting mods 11/15/95 for Layer I ******************************************************************/ /****************************************************************** MPEG audio software decoder portable ANSI c. Decodes all Layer I/II to 16 bit linear pcm. Optional stereo to mono conversion. Optional output sample rate conversion to half or quarter of native mpeg rate. dec8.c adds oupuut conversion features. ------------------------------------- int audio_decode_init(MPEG *m, MPEG_HEAD *h, int framebytes_arg, int reduction_code, int transform_code, int convert_code, int freq_limit) initilize decoder: return 0 = fail, not 0 = success MPEG *m input, mpeg structure for multiple streams MPEG_HEAD *h input, mpeg header info (returned by call to head_info) framebytes input, mpeg frame size (returned by call to head_info) reduction_code input, sample rate reduction code 0 = full rate 1 = half rate 2 = quarter rate transform_code input, ignored convert_code input, channel conversion convert_code: 0 = two chan output 1 = convert two chan to mono 2 = convert two chan to left chan 3 = convert two chan to right chan freq_limit input, limits bandwidth of pcm output to specified frequency. Special use. Set to 24000 for normal use. --------------------------------- void audio_decode_info( MPEG *m, DEC_INFO *info) MPEG *m input, mpeg structure for multiple streams information return: Call after audio_decode_init. See mhead.h for information returned in DEC_INFO structure. --------------------------------- IN_OUT audio_decode(unsigned char *bs, void *pcmbuf) decode one mpeg audio frame: bs input, mpeg bitstream, must start with sync word. Caution: may read up to 3 bytes beyond end of frame. pcmbuf output, pcm samples. IN_OUT structure returns: Number bytes conceptually removed from mpeg bitstream. Returns 0 if sync loss. Number bytes of pcm output. *******************************************************************/ #include #include #include #include #include "L3.h" #include "mhead.h" /* mpeg header structure */ #ifdef _MSC_VER #pragma warning(disable: 4709) #endif /*------------------------------------------------------- NOTE: Decoder may read up to three bytes beyond end of frame. Calling application must ensure that this does not cause a memory access violation (protection fault) ---------------------------------------------------------*/ /*====================================================================*/ /*----------------*/ /* Read Only */ static int look_joint[16] = { /* lookup stereo sb's by mode+ext */ 64, 64, 64, 64, /* stereo */ 2 * 4, 2 * 8, 2 * 12, 2 * 16, /* joint */ 64, 64, 64, 64, /* dual */ 32, 32, 32, 32, /* mono */ }; /* Okay to be global */ /* Read Only */ static int bat_bit_master[] = { 0, 5, 7, 9, 10, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48}; void sbt_mono(MPEG *m, float *sample, short *pcm, int n); void sbt_dual(MPEG *m, float *sample, short *pcm, int n); IN_OUT L2audio_decode(void *mv, unsigned char *bs, signed short *pcm); /*======================================================================*/ /*======================================================================*/ /*------------- initialize bit getter -------------*/ static void load_init(MPEG *m, unsigned char *buf) { m->cup.bs_ptr = buf; m->cup.bits = 0; m->cup.bitbuf = 0; } /*------------- get n bits from bitstream -------------*/ static long load(MPEG *m, int n) { unsigned long x; if (m->cup.bits < n) { /* refill bit buf if necessary */ while (m->cup.bits <= 24) { m->cup.bitbuf = (m->cup.bitbuf << 8) | *m->cup.bs_ptr++; m->cup.bits += 8; } } m->cup.bits -= n; x = m->cup.bitbuf >> m->cup.bits; m->cup.bitbuf -= x << m->cup.bits; return x; } /*------------- skip over n bits in bitstream -------------*/ static void skip(MPEG *m, int n) { int k; if (m->cup.bits < n) { n -= m->cup.bits; k = n >> 3; /*--- bytes = n/8 --*/ m->cup.bs_ptr += k; n -= k << 3; m->cup.bitbuf = *m->cup.bs_ptr++; m->cup.bits = 8; } m->cup.bits -= n; m->cup.bitbuf -= (m->cup.bitbuf >> m->cup.bits) << m->cup.bits; } /*--------------------------------------------------------------*/ #define mac_load_check(n) if( m->cup.bits < (n) ) { \ while( m->cup.bits <= 24 ) { \ m->cup.bitbuf = (m->cup.bitbuf << 8) | *m->cup.bs_ptr++; \ m->cup.bits += 8; \ } \ } /*--------------------------------------------------------------*/ #define mac_load(n) ( m->cup.bits -= n, \ m->cup.bitval = m->cup.bitbuf >> m->cup.bits, \ m->cup.bitbuf -= m->cup.bitval << m->cup.bits, \ m->cup.bitval ) /*======================================================================*/ static void unpack_ba(MPEG *m) { int i, j, k; /* Read Only */ static int nbit[4] = {4, 4, 3, 2}; int nstereo; m->cup.bit_skip = 0; nstereo = m->cup.stereo_sb; k = 0; for (i = 0; i < 4; i++) { for (j = 0; j < m->cup.nbat[i]; j++, k++) { mac_load_check(4); m->cup.ballo[k] = m->cup.samp_dispatch[k] = m->cup.bat[i][mac_load(nbit[i])]; if (k >= m->cup.nsb_limit) m->cup.bit_skip += bat_bit_master[m->cup.samp_dispatch[k]]; m->cup.c_value[k] = m->cup.look_c_value[m->cup.samp_dispatch[k]]; if (--nstereo < 0) { m->cup.ballo[k + 1] = m->cup.ballo[k]; m->cup.samp_dispatch[k] += 18; /* flag as joint */ m->cup.samp_dispatch[k + 1] = m->cup.samp_dispatch[k]; /* flag for sf */ m->cup.c_value[k + 1] = m->cup.c_value[k]; k++; j++; } } } m->cup.samp_dispatch[m->cup.nsb_limit] = 37; /* terminate the dispatcher with skip */ m->cup.samp_dispatch[k] = 36; /* terminate the dispatcher */ } /*-------------------------------------------------------------------------*/ static void unpack_sfs(MPEG *m) /* unpack scale factor selectors */ { int i; for (i = 0; i < m->cup.max_sb; i++) { mac_load_check(2); if (m->cup.ballo[i]) m->cup.sf_dispatch[i] = mac_load(2); else m->cup.sf_dispatch[i] = 4; /* no allo */ } m->cup.sf_dispatch[i] = 5; /* terminate dispatcher */ } /*-------------------------------------------------------------------------*/ static void unpack_sf(MPEG *m) /* unpack scale factor */ { /* combine dequant and scale factors */ int i; i = -1; dispatch:switch (m->cup.sf_dispatch[++i]) { case 0: /* 3 factors 012 */ mac_load_check(18); m->cup.cs_factor[0][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; m->cup.cs_factor[1][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; m->cup.cs_factor[2][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; goto dispatch; case 1: /* 2 factors 002 */ mac_load_check(12); m->cup.cs_factor[1][i] = m->cup.cs_factor[0][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; m->cup.cs_factor[2][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; goto dispatch; case 2: /* 1 factor 000 */ mac_load_check(6); m->cup.cs_factor[2][i] = m->cup.cs_factor[1][i] = m->cup.cs_factor[0][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; goto dispatch; case 3: /* 2 factors 022 */ mac_load_check(12); m->cup.cs_factor[0][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; m->cup.cs_factor[2][i] = m->cup.cs_factor[1][i] = m->cup.c_value[i] * m->cup.sf_table[mac_load(6)]; goto dispatch; case 4: /* no allo */ /*-- m->cup.cs_factor[2][i] = m->cup.cs_factor[1][i] = m->cup.cs_factor[0][i] = 0.0; --*/ goto dispatch; case 5: /* all done */ ; } /* end switch */ } /*-------------------------------------------------------------------------*/ #define UNPACK_N(n) s[k] = m->cup.cs_factor[i][k]*(load(m,n)-((1 << (n-1)) -1)); \ s[k+64] = m->cup.cs_factor[i][k]*(load(m,n)-((1 << (n-1)) -1)); \ s[k+128] = m->cup.cs_factor[i][k]*(load(m,n)-((1 << (n-1)) -1)); \ goto dispatch; #define UNPACK_N2(n) mac_load_check(3*n); \ s[k] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ s[k+64] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ s[k+128] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ goto dispatch; #define UNPACK_N3(n) mac_load_check(2*n); \ s[k] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ s[k+64] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ mac_load_check(n); \ s[k+128] = m->cup.cs_factor[i][k]*(mac_load(n)-((1 << (n-1)) -1)); \ goto dispatch; #define UNPACKJ_N(n) tmp = (load(m,n)-((1 << (n-1)) -1)); \ s[k] = m->cup.cs_factor[i][k]*tmp; \ s[k+1] = m->cup.cs_factor[i][k+1]*tmp; \ tmp = (load(m,n)-((1 << (n-1)) -1)); \ s[k+64] = m->cup.cs_factor[i][k]*tmp; \ s[k+64+1] = m->cup.cs_factor[i][k+1]*tmp; \ tmp = (load(m,n)-((1 << (n-1)) -1)); \ s[k+128] = m->cup.cs_factor[i][k]*tmp; \ s[k+128+1] = m->cup.cs_factor[i][k+1]*tmp; \ k++; /* skip right chan dispatch */ \ goto dispatch; /*-------------------------------------------------------------------------*/ static void unpack_samp(MPEG *m) /* unpack samples */ { int i, j, k; float *s; int n; long tmp; s = m->cup.sample; for (i = 0; i < 3; i++) { /* 3 groups of scale factors */ for (j = 0; j < 4; j++) { k = -1; dispatch:switch (m->cup.samp_dispatch[++k]) { case 0: s[k + 128] = s[k + 64] = s[k] = 0.0F; goto dispatch; case 1: /* 3 levels grouped 5 bits */ mac_load_check(5); n = mac_load(5); s[k] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][2]; goto dispatch; case 2: /* 5 levels grouped 7 bits */ mac_load_check(7); n = mac_load(7); s[k] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][2]; goto dispatch; case 3: UNPACK_N2(3) /* 7 levels */ case 4: /* 9 levels grouped 10 bits */ mac_load_check(10); n = mac_load(10); s[k] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][2]; goto dispatch; case 5: UNPACK_N2(4) /* 15 levels */ case 6: UNPACK_N2(5) /* 31 levels */ case 7: UNPACK_N2(6) /* 63 levels */ case 8: UNPACK_N2(7) /* 127 levels */ case 9: UNPACK_N2(8) /* 255 levels */ case 10: UNPACK_N3(9) /* 511 levels */ case 11: UNPACK_N3(10) /* 1023 levels */ case 12: UNPACK_N3(11) /* 2047 levels */ case 13: UNPACK_N3(12) /* 4095 levels */ case 14: UNPACK_N(13) /* 8191 levels */ case 15: UNPACK_N(14) /* 16383 levels */ case 16: UNPACK_N(15) /* 32767 levels */ case 17: UNPACK_N(16) /* 65535 levels */ /* -- joint ---- */ case 18 + 0: s[k + 128 + 1] = s[k + 128] = s[k + 64 + 1] = s[k + 64] = s[k + 1] = s[k] = 0.0F; k++; /* skip right chan dispatch */ goto dispatch; case 18 + 1: /* 3 levels grouped 5 bits */ n = load(m,5); s[k] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][0]; s[k + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group3_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][1]; s[k + 64 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group3_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group3_table[n][2]; s[k + 128 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group3_table[n][2]; k++; /* skip right chan dispatch */ goto dispatch; case 18 + 2: /* 5 levels grouped 7 bits */ n = load(m,7); s[k] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][0]; s[k + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group5_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][1]; s[k + 64 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group5_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group5_table[n][2]; s[k + 128 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group5_table[n][2]; k++; /* skip right chan dispatch */ goto dispatch; case 18 + 3: UNPACKJ_N(3) /* 7 levels */ case 18 + 4: /* 9 levels grouped 10 bits */ n = load(m,10); s[k] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][0]; s[k + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group9_table[n][0]; s[k + 64] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][1]; s[k + 64 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group9_table[n][1]; s[k + 128] = m->cup.cs_factor[i][k] * m->cup.group9_table[n][2]; s[k + 128 + 1] = m->cup.cs_factor[i][k + 1] * m->cup.group9_table[n][2]; k++; /* skip right chan dispatch */ goto dispatch; case 18 + 5: UNPACKJ_N(4) /* 15 levels */ case 18 + 6: UNPACKJ_N(5) /* 31 levels */ case 18 + 7: UNPACKJ_N(6) /* 63 levels */ case 18 + 8: UNPACKJ_N(7) /* 127 levels */ case 18 + 9: UNPACKJ_N(8) /* 255 levels */ case 18 + 10: UNPACKJ_N(9) /* 511 levels */ case 18 + 11: UNPACKJ_N(10) /* 1023 levels */ case 18 + 12: UNPACKJ_N(11) /* 2047 levels */ case 18 + 13: UNPACKJ_N(12) /* 4095 levels */ case 18 + 14: UNPACKJ_N(13) /* 8191 levels */ case 18 + 15: UNPACKJ_N(14) /* 16383 levels */ case 18 + 16: UNPACKJ_N(15) /* 32767 levels */ case 18 + 17: UNPACKJ_N(16) /* 65535 levels */ /* -- end of dispatch -- */ case 37: skip(m, m->cup.bit_skip); case 36: s += 3 * 64; } /* end switch */ } /* end j loop */ } /* end i loop */ } /*-------------------------------------------------------------------------*/ IN_OUT audio_decode(MPEG *m, unsigned char *bs, signed short *pcm) { return m->cup.audio_decode_routine(m, bs, pcm); } /*-------------------------------------------------------------------------*/ IN_OUT L2audio_decode(void *mv, unsigned char *bs, signed short *pcm) { MPEG *m = mv; int sync, prot; IN_OUT in_out; load_init(m, bs); /* initialize bit getter */ /* test sync */ in_out.in_bytes = 0; /* assume fail */ in_out.out_bytes = 0; sync = load(m,12); if (sync != 0xFFF) return in_out; /* sync fail */ load(m,3); /* skip id and option (checked by init) */ prot = load(m,1); /* load prot bit */ load(m,6); /* skip to pad */ m->cup.pad = load(m,1); load(m,1); /* skip to mode */ m->cup.stereo_sb = look_joint[load(m,4)]; if (prot) load(m,4); /* skip to data */ else load(m,20); /* skip crc */ unpack_ba(m); /* unpack bit allocation */ unpack_sfs(m); /* unpack scale factor selectors */ unpack_sf(m); /* unpack scale factor */ unpack_samp(m); /* unpack samples */ m->cup.sbt(m, m->cup.sample, pcm, 36); /*-----------*/ in_out.in_bytes = m->cup.framebytes + m->cup.pad; in_out.out_bytes = m->cup.outbytes; return in_out; } /*-------------------------------------------------------------------------*/ #include "cupini.c" /* initialization */ #include "cupL1.c" /* Layer I */ /*-------------------------------------------------------------------------*/