Diff: layer12.cpp

Revision:

4:30b2cf4a8ee2

Parent:

3:6f07b5f52c38

Child:

5:50015f4868e2

--- a/layer12.cpp	Wed Dec 19 06:01:00 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,529 +0,0 @@
-/*
- * libmad - MPEG audio decoder library
- * Copyright (C) 2000-2004 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: layer12.c,v 1.1 2010/11/23 20:12:57 andy Exp $
- */
-
-#  include "config.h"
-
-# include "global.h"
-
-# 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 "layer12.h"
-
-/*
- * scalefactor table
- * used in both Layer I and Layer II decoding
- */
-# include "sf_table.h"
-
-/* --- Layer I ------------------------------------------------------------- */
-
-/* linear scaling table */
-static
-mad_fixed_t const linear_table[14] = {
-  MAD_F(0x15555555),  /* 2^2  / (2^2  - 1) == 1.33333333333333 */
-  MAD_F(0x12492492),  /* 2^3  / (2^3  - 1) == 1.14285714285714 */
-  MAD_F(0x11111111),  /* 2^4  / (2^4  - 1) == 1.06666666666667 */
-  MAD_F(0x10842108),  /* 2^5  / (2^5  - 1) == 1.03225806451613 */
-  MAD_F(0x10410410),  /* 2^6  / (2^6  - 1) == 1.01587301587302 */
-  MAD_F(0x10204081),  /* 2^7  / (2^7  - 1) == 1.00787401574803 */
-  MAD_F(0x10101010),  /* 2^8  / (2^8  - 1) == 1.00392156862745 */
-  MAD_F(0x10080402),  /* 2^9  / (2^9  - 1) == 1.00195694716243 */
-  MAD_F(0x10040100),  /* 2^10 / (2^10 - 1) == 1.00097751710655 */
-  MAD_F(0x10020040),  /* 2^11 / (2^11 - 1) == 1.00048851978505 */
-  MAD_F(0x10010010),  /* 2^12 / (2^12 - 1) == 1.00024420024420 */
-  MAD_F(0x10008004),  /* 2^13 / (2^13 - 1) == 1.00012208521548 */
-  MAD_F(0x10004001),  /* 2^14 / (2^14 - 1) == 1.00006103888177 */
-  MAD_F(0x10002000)   /* 2^15 / (2^15 - 1) == 1.00003051850948 */
-};
-
-/*
- * NAME:    I_sample()
- * DESCRIPTION:    decode one requantized Layer I sample from a bitstream
- */
-static
-mad_fixed_t I_sample(struct mad_bitptr *ptr, unsigned int nb)
-{
-  mad_fixed_t sample;
-
-  sample = mad_bit_read(ptr, nb);
-
-  /* invert most significant bit, extend sign, then scale to fixed format */
-
-  sample ^= 1 << (nb - 1);
-  sample |= -(sample & (1 << (nb - 1)));
-
-  sample <<= MAD_F_FRACBITS - (nb - 1);
-
-  /* requantize the sample */
-
-  /* s'' = (2^nb / (2^nb - 1)) * (s''' + 2^(-nb + 1)) */
-
-  sample += MAD_F_ONE >> (nb - 1);
-
-  return mad_f_mul(sample, linear_table[nb - 2]);
-
-  /* s' = factor * s'' */
-  /* (to be performed by caller) */
-}
-
-/*
- * NAME:    layer->I()
- * DESCRIPTION:    decode a single Layer I frame
- */
-int mad_layer_I(struct mad_stream *stream, struct mad_frame *frame)
-{
-  struct mad_header *header = &frame->header;
-  unsigned int nch, bound, ch, s, sb, nb;
-  unsigned char allocation[2][32], scalefactor[2][32];
-
-  nch = MAD_NCHANNELS(header);
-
-  bound = 32;
-  if (header->mode == MAD_MODE_JOINT_STEREO) {
-    header->flags |= MAD_FLAG_I_STEREO;
-    bound = 4 + header->mode_extension * 4;
-  }
-
-  /* check CRC word */
-
-  if (header->flags & MAD_FLAG_PROTECTION) {
-    header->crc_check =
-      mad_bit_crc(stream->ptr, 4 * (bound * nch + (32 - bound)),
-          header->crc_check);
-
-    if (header->crc_check != header->crc_target &&
-    !(frame->options & MAD_OPTION_IGNORECRC)) {
-      stream->error = MAD_ERROR_BADCRC;
-      return -1;
-    }
-  }
-
-  /* decode bit allocations */
-
-  for (sb = 0; sb < bound; ++sb) {
-    for (ch = 0; ch < nch; ++ch) {
-      nb = mad_bit_read(&stream->ptr, 4);
-
-      if (nb == 15) {
-    stream->error = MAD_ERROR_BADBITALLOC;
-    return -1;
-      }
-
-      allocation[ch][sb] = nb ? nb + 1 : 0;
-    }
-  }
-
-  for (sb = bound; sb < 32; ++sb) {
-    nb = mad_bit_read(&stream->ptr, 4);
-
-    if (nb == 15) {
-      stream->error = MAD_ERROR_BADBITALLOC;
-      return -1;
-    }
-
-    allocation[0][sb] =
-    allocation[1][sb] = nb ? nb + 1 : 0;
-  }
-
-  /* decode scalefactors */
-
-  for (sb = 0; sb < 32; ++sb) {
-    for (ch = 0; ch < nch; ++ch) {
-      if (allocation[ch][sb]) {
-    scalefactor[ch][sb] = mad_bit_read(&stream->ptr, 6);
-
-# if defined(OPT_STRICT)
-    /*
-     * Scalefactor index 63 does not appear in Table B.1 of
-     * ISO/IEC 11172-3. Nonetheless, other implementations accept it,
-     * so we only reject it if OPT_STRICT is defined.
-     */
-    if (scalefactor[ch][sb] == 63) {
-      stream->error = MAD_ERROR_BADSCALEFACTOR;
-      return -1;
-    }
-# endif
-      }
-    }
-  }
-
-  /* decode samples */
-
-  for (s = 0; s < 12; ++s) {
-    for (sb = 0; sb < bound; ++sb) {
-      for (ch = 0; ch < nch; ++ch) {
-    nb = allocation[ch][sb];
-    frame->sbsample[ch][s][sb] = nb ?
-      mad_f_mul(I_sample(&stream->ptr, nb),
-            sf_table[scalefactor[ch][sb]]) : 0;
-      }
-    }
-
-    for (sb = bound; sb < 32; ++sb) {
-      if ((nb = allocation[0][sb]) != 0) {
-    mad_fixed_t sample;
-
-    sample = I_sample(&stream->ptr, nb);
-
-    for (ch = 0; ch < nch; ++ch) {
-      frame->sbsample[ch][s][sb] =
-        mad_f_mul(sample, sf_table[scalefactor[ch][sb]]);
-    }
-      }
-      else {
-    for (ch = 0; ch < nch; ++ch)
-      frame->sbsample[ch][s][sb] = 0;
-      }
-    }
-  }
-
-  return 0;
-}
-
-/* --- Layer II ------------------------------------------------------------ */
-
-/* possible quantization per subband table */
-static
-const struct {
-  unsigned int sblimit;
-  unsigned char offsets[30];
-} sbquant_table[5] = {
-  /* ISO/IEC 11172-3 Table B.2a */
-  { 27, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3,    /* 0 */
-      3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 } },
-  /* ISO/IEC 11172-3 Table B.2b */
-  { 30, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3,    /* 1 */
-      3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0 } },
-  /* ISO/IEC 11172-3 Table B.2c */
-  {  8, { 5, 5, 2, 2, 2, 2, 2, 2 } },                /* 2 */
-  /* ISO/IEC 11172-3 Table B.2d */
-  { 12, { 5, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 } },        /* 3 */
-  /* ISO/IEC 13818-3 Table B.1 */
-  { 30, { 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1,    /* 4 */
-      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } }
-};
-
-/* bit allocation table */
-static
-struct {
-  unsigned short nbal;
-  unsigned short offset;
-} const bitalloc_table[8] = {
-  { 2, 0 },  /* 0 */
-  { 2, 3 },  /* 1 */
-  { 3, 3 },  /* 2 */
-  { 3, 1 },  /* 3 */
-  { 4, 2 },  /* 4 */
-  { 4, 3 },  /* 5 */
-  { 4, 4 },  /* 6 */
-  { 4, 5 }   /* 7 */
-};
-
-/* offsets into quantization class table */
-static
-unsigned char const offset_table[6][15] = {
-  { 0, 1, 16                                             },  /* 0 */
-  { 0, 1,  2, 3, 4, 5, 16                                },  /* 1 */
-  { 0, 1,  2, 3, 4, 5,  6, 7,  8,  9, 10, 11, 12, 13, 14 },  /* 2 */
-  { 0, 1,  3, 4, 5, 6,  7, 8,  9, 10, 11, 12, 13, 14, 15 },  /* 3 */
-  { 0, 1,  2, 3, 4, 5,  6, 7,  8,  9, 10, 11, 12, 13, 16 },  /* 4 */
-  { 0, 2,  4, 5, 6, 7,  8, 9, 10, 11, 12, 13, 14, 15, 16 }   /* 5 */
-};
-
-/* quantization class table */
-static
-struct quantclass {
-  unsigned short nlevels;
-  unsigned char group;
-  unsigned char bits;
-  mad_fixed_t C;
-  mad_fixed_t D;
-} const qc_table[17] = {
-# include "qc_table.h"
-};
-
-/*
- * NAME:    II_samples()
- * DESCRIPTION:    decode three requantized Layer II samples from a bitstream
- */
-static
-void II_samples(struct mad_bitptr *ptr,
-        struct quantclass const *quantclass,
-        mad_fixed_t output[3])
-{
-  unsigned int nb, s, sample[3];
-
-  if ((nb = quantclass->group) != 0) {
-    unsigned int c, nlevels;
-
-    /* degrouping */
-    c = mad_bit_read(ptr, quantclass->bits);
-    nlevels = quantclass->nlevels;
-
-    for (s = 0; s < 3; ++s) {
-      sample[s] = c % nlevels;
-      c /= nlevels;
-    }
-  }
-  else {
-    nb = quantclass->bits;
-
-    for (s = 0; s < 3; ++s)
-      sample[s] = mad_bit_read(ptr, nb);
-  }
-
-  for (s = 0; s < 3; ++s) {
-    mad_fixed_t requantized;
-
-    /* invert most significant bit, extend sign, then scale to fixed format */
-
-    requantized  = sample[s] ^ (1 << (nb - 1));
-    requantized |= -(requantized & (1 << (nb - 1)));
-
-    requantized <<= MAD_F_FRACBITS - (nb - 1);
-
-    /* requantize the sample */
-
-    /* s'' = C * (s''' + D) */
-
-    output[s] = mad_f_mul(requantized + quantclass->D, quantclass->C);
-
-    /* s' = factor * s'' */
-    /* (to be performed by caller) */
-  }
-}
-
-/*
- * NAME:    layer->II()
- * DESCRIPTION:    decode a single Layer II frame
- */
-int mad_layer_II(struct mad_stream *stream, struct mad_frame *frame)
-{
-  struct mad_header *header = &frame->header;
-  struct mad_bitptr start;
-  unsigned int index, sblimit, nbal, nch, bound, gr, ch, s, sb;
-  unsigned char const *offsets;
-  unsigned char allocation[2][32], scfsi[2][32], scalefactor[2][32][3];
-  mad_fixed_t samples[3];
-
-  nch = MAD_NCHANNELS(header);
-
-  if (header->flags & MAD_FLAG_LSF_EXT)
-    index = 4;
-  else if (header->flags & MAD_FLAG_FREEFORMAT)
-    goto freeformat;
-  else {
-    unsigned long bitrate_per_channel;
-
-    bitrate_per_channel = header->bitrate;
-    if (nch == 2) {
-      bitrate_per_channel /= 2;
-
-# if defined(OPT_STRICT)
-      /*
-       * ISO/IEC 11172-3 allows only single channel mode for 32, 48, 56, and
-       * 80 kbps bitrates in Layer II, but some encoders ignore this
-       * restriction. We enforce it if OPT_STRICT is defined.
-       */
-      if (bitrate_per_channel <= 28000 || bitrate_per_channel == 40000) {
-    stream->error = MAD_ERROR_BADMODE;
-    return -1;
-      }
-# endif
-    }
-    else {  /* nch == 1 */
-      if (bitrate_per_channel > 192000) {
-    /*
-     * ISO/IEC 11172-3 does not allow single channel mode for 224, 256,
-     * 320, or 384 kbps bitrates in Layer II.
-     */
-    stream->error = MAD_ERROR_BADMODE;
-    return -1;
-      }
-    }
-
-    if (bitrate_per_channel <= 48000)
-      index = (header->samplerate == 32000) ? 3 : 2;
-    else if (bitrate_per_channel <= 80000)
-      index = 0;
-    else {
-    freeformat:
-      index = (header->samplerate == 48000) ? 0 : 1;
-    }
-  }
-
-  sblimit = sbquant_table[index].sblimit;
-  offsets = sbquant_table[index].offsets;
-
-  bound = 32;
-  if (header->mode == MAD_MODE_JOINT_STEREO) {
-    header->flags |= MAD_FLAG_I_STEREO;
-    bound = 4 + header->mode_extension * 4;
-  }
-
-  if (bound > sblimit)
-    bound = sblimit;
-
-  start = stream->ptr;
-
-  /* decode bit allocations */
-
-  for (sb = 0; sb < bound; ++sb) {
-    nbal = bitalloc_table[offsets[sb]].nbal;
-
-    for (ch = 0; ch < nch; ++ch)
-      allocation[ch][sb] = mad_bit_read(&stream->ptr, nbal);
-  }
-
-  for (sb = bound; sb < sblimit; ++sb) {
-    nbal = bitalloc_table[offsets[sb]].nbal;
-
-    allocation[0][sb] =
-    allocation[1][sb] = mad_bit_read(&stream->ptr, nbal);
-  }
-
-  /* decode scalefactor selection info */
-
-  for (sb = 0; sb < sblimit; ++sb) {
-    for (ch = 0; ch < nch; ++ch) {
-      if (allocation[ch][sb])
-    scfsi[ch][sb] = mad_bit_read(&stream->ptr, 2);
-    }
-  }
-
-  /* check CRC word */
-
-  if (header->flags & MAD_FLAG_PROTECTION) {
-    header->crc_check =
-      mad_bit_crc(start, mad_bit_length(&start, &stream->ptr),
-          header->crc_check);
-
-    if (header->crc_check != header->crc_target &&
-    !(frame->options & MAD_OPTION_IGNORECRC)) {
-      stream->error = MAD_ERROR_BADCRC;
-      return -1;
-    }
-  }
-
-  /* decode scalefactors */
-
-  for (sb = 0; sb < sblimit; ++sb) {
-    for (ch = 0; ch < nch; ++ch) {
-      if (allocation[ch][sb]) {
-    scalefactor[ch][sb][0] = mad_bit_read(&stream->ptr, 6);
-
-    switch (scfsi[ch][sb]) {
-    case 2:
-      scalefactor[ch][sb][2] =
-      scalefactor[ch][sb][1] =
-      scalefactor[ch][sb][0];
-      break;
-
-    case 0:
-      scalefactor[ch][sb][1] = mad_bit_read(&stream->ptr, 6);
-      /* fall through */
-
-    case 1:
-    case 3:
-      scalefactor[ch][sb][2] = mad_bit_read(&stream->ptr, 6);
-    }
-
-    if (scfsi[ch][sb] & 1)
-      scalefactor[ch][sb][1] = scalefactor[ch][sb][scfsi[ch][sb] - 1];
-
-# if defined(OPT_STRICT)
-    /*
-     * Scalefactor index 63 does not appear in Table B.1 of
-     * ISO/IEC 11172-3. Nonetheless, other implementations accept it,
-     * so we only reject it if OPT_STRICT is defined.
-     */
-    if (scalefactor[ch][sb][0] == 63 ||
-        scalefactor[ch][sb][1] == 63 ||
-        scalefactor[ch][sb][2] == 63) {
-      stream->error = MAD_ERROR_BADSCALEFACTOR;
-      return -1;
-    }
-# endif
-      }
-    }
-  }
-
-  /* decode samples */
-
-  for (gr = 0; gr < 12; ++gr) {
-    for (sb = 0; sb < bound; ++sb) {
-      for (ch = 0; ch < nch; ++ch) {
-    if ((index = allocation[ch][sb]) != 0) {
-      index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1];
-
-      II_samples(&stream->ptr, &qc_table[index], samples);
-
-      for (s = 0; s < 3; ++s) {
-        frame->sbsample[ch][3 * gr + s][sb] =
-          mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]);
-      }
-    }
-    else {
-      for (s = 0; s < 3; ++s)
-        frame->sbsample[ch][3 * gr + s][sb] = 0;
-    }
-      }
-    }
-
-    for (sb = bound; sb < sblimit; ++sb) {
-      if ((index = allocation[0][sb])!= 0) {
-    index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1];
-
-    II_samples(&stream->ptr, &qc_table[index], samples);
-
-    for (ch = 0; ch < nch; ++ch) {
-      for (s = 0; s < 3; ++s) {
-        frame->sbsample[ch][3 * gr + s][sb] =
-          mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]);
-      }
-    }
-      }
-      else {
-    for (ch = 0; ch < nch; ++ch) {
-      for (s = 0; s < 3; ++s)
-        frame->sbsample[ch][3 * gr + s][sb] = 0;
-    }
-      }
-    }
-
-    for (ch = 0; ch < nch; ++ch) {
-      for (s = 0; s < 3; ++s) {
-    for (sb = sblimit; sb < 32; ++sb)
-      frame->sbsample[ch][3 * gr + s][sb] = 0;
-      }
-    }
-  }
-
-  return 0;
-}