AC-3 decoder, soc revision 9, Jun 14 03:52:02 2006 UTC by cloud9

initial commit
NOTE: This and all subsequent ac3dec.c revisions from the soc repository
violate the GPL. This will be fixed after all soc revisions are imported.
This file is not compiled yet, so the license compliance of any builds in
the meantime will not be affected.

Originally committed as revision 9651 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3dec.c

+/* AC3 Audio Decoder.
+ *
+ * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <math.h>
+#include <inttypes.h>
+#include <string.h>
+
+#define ALT_BITSTREAM_READER
+#include "ac3_decoder.h"
+#include "avcodec.h"
+#include "bitstream.h"
+#include "dsputil.h"
+#include "avutil.h"
+
+static const int sampling_rates[3] = { 32000, 44100, 48000 };
+
+static const struct
+{
+  int bit_rate;
+  int frame_sizes[3];
+} frame_size_table[38] = {
+  { 32, { 96, 69, 64 } },
+  { 32, { 96, 70, 64 } },
+  { 40, { 120, 87, 80 } },
+  { 40, { 120, 88, 80 } },
+  { 48, { 144, 104, 96 } },
+  { 48, { 144, 105, 96 } },
+  { 56, { 168, 121, 112 } },
+  { 56, { 168, 122, 112 } },
+  { 64, { 192, 139, 128 } },
+  { 64, { 192, 140, 128 } },
+  { 80, { 240, 174, 160 } },
+  { 80, { 240, 175, 160 } },
+  { 96, { 288, 208, 192 } },
+  { 96, { 288, 209, 192 } },
+  { 112, { 336, 243, 224 } },
+  { 112, { 336, 244, 224 } },
+  { 128, { 384, 278, 256 } },
+  { 128, { 384, 279, 256 } },
+  { 160, { 480, 348, 320 } },
+  { 160, { 480, 349, 320 } },
+  { 192, { 576, 417, 384 } },
+  { 192, { 576, 418, 384 } },
+  { 224, { 672, 487, 448 } },
+  { 224, { 672, 488, 448 } },
+  { 256, { 768, 557, 512 } },
+  { 256, { 768, 558, 512 } },
+  { 320, { 960, 696, 640 } },
+  { 320, { 960, 697, 640 } },
+  { 384, { 1152, 835, 768 } },
+  { 384, { 1152, 836, 768 } },
+  { 448, { 1344, 975, 896 } },
+  { 448, { 1344, 976, 896 } },
+  { 512, { 1536, 1114, 1024 } },
+  { 512, { 1536, 1115, 1024 } },
+  { 576, { 1728, 1253, 1152 } },
+  { 576, { 1728, 1254, 1152 } },
+  { 640, { 1920, 1393, 1280 } }
+};
+
+static int
+ac3_decode_init (AVCodecContext * avctx)
+{
+  AC3DecodeContext *ctx = avctx->priv_data;
+
+  ff_mdct_init (&ctx->mdct_ctx_256, 8, 1);
+  ff_mdct_init (&ctx->mdct_ctx_512, 9, 1);
+  ctx->samples = av_mallocz (6 * 6 * 256 * sizeof (float));
+  if (!(ctx->samples))
+    return -1;
+
+  return 0;
+}
+
+static int
+ac3_synchronize (uint8_t * buf, int buf_size)
+{
+  int i;
+
+  for (i = 0; i < buf_size - 1; i++)
+    if (buf[i] == 0x0b && buf[i + 1] == 0x77)
+      return i;
+
+  return -1;
+}
+
+//Returns -1 when 'fscod' is not valid;
+static int
+ac3_parse_sync_info (AC3DecodeContext * ctx)
+{
+  ac3_sync_info *sync_info = &ctx->sync_info;
+  GetBitContext *gb = &ctx->gb;
+
+  sync_info->sync_word = get_bits_long (gb, 16);
+  sync_info->crc1 = get_bits_long (gb, 16);
+  sync_info->fscod = get_bits_long (gb, 2);
+  if (sync_info->fscod == 0x03)
+    return -1;
+  sync_info->frmsizecod = get_bits_long (gb, 6);
+  if (sync_info->frmsizecod >= 0x38)
+    return -1;
+  sync_info->sampling_rate = sampling_rates[sync_info->fscod];
+  sync_info->bit_rate = frame_size_table[sync_info->frmsizecod].bit_rate;
+  sync_info->frame_size = frame_size_table[sync_info->frmsizecod].frame_sizes[sync_info->fscod];
+
+  return 0;
+}
+
+static const int nfchans_tbl[8] = { 2, 1, 2, 3, 3, 4, 4, 5 };
+
+//Returns -1 when
+static int
+ac3_parse_bsi (AC3DecodeContext * ctx)
+{
+  ac3_bsi *bsi = &ctx->bsi;
+  uint32_t *flags = &bsi->flags;
+  GetBitContext *gb = &ctx->gb;
+
+  *flags = 0;
+  bsi->cmixlev = 0;
+  bsi->surmixlev = 0;
+  bsi->dsurmod = 0;
+
+  bsi->bsid = get_bits_long (gb, 5);
+  if (bsi->bsid > 0x08)
+    return -1;
+  bsi->bsmod = get_bits_long (gb, 3);
+  bsi->acmod = get_bits_long (gb, 3);
+  if (bsi->acmod & 0x01 && bsi->acmod != 0x01)
+    bsi->cmixlev = get_bits_long (gb, 2);
+  if (bsi->acmod & 0x04)
+    bsi->surmixlev = get_bits_long (gb, 2);
+  if (bsi->acmod == 0x02)
+    bsi->dsurmod = get_bits_long (gb, 2);
+  if (get_bits_long (gb, 1))
+    *flags |= AC3_BSI_LFEON;
+  bsi->dialnorm = get_bits_long (gb, 5);
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_COMPRE;
+    bsi->compr = get_bits_long (gb, 5);
+  }
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_LANGCODE;
+    bsi->langcod = get_bits_long (gb, 8);
+  }
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_AUDPRODIE;
+    bsi->mixlevel = get_bits_long (gb, 5);
+    bsi->roomtyp = get_bits_long (gb, 2);
+  }
+  if (bsi->acmod == 0x00) {
+    bsi->dialnorm2 = get_bits_long (gb, 5);
+    if (get_bits_long (gb, 1)) {
+      *flags |= AC3_BSI_COMPR2E;
+      bsi->compr2 = get_bits_long (gb, 5);
+    }
+    if (get_bits_long (gb, 1)) {
+      *flags |= AC3_BSI_LANGCOD2E;
+      bsi->langcod2 = get_bits_long (gb, 8);
+    }
+    if (get_bits_long (gb, 1)) {
+      *flags |= AC3_BSI_AUDPRODIE;
+      bsi->mixlevel2 = get_bits_long (gb, 5);
+      bsi->roomtyp2 = get_bits_long (gb, 2);
+    }
+  }
+  if (get_bits_long (gb, 1))
+    *flags |= AC3_BSI_COPYRIGHTB;
+  if (get_bits_long (gb, 1))
+    *flags |= AC3_BSI_ORIGBS;
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_TIMECOD1E;
+    bsi->timecod1 = get_bits_long (gb, 14);
+  }
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_TIMECOD2E;
+    bsi->timecod2 = get_bits_long (gb, 14);
+  }
+  if (get_bits_long (gb, 1)) {
+    *flags |= AC3_BSI_ADDBSIE;
+    bsi->addbsil = get_bits_long (gb, 6);
+    do {
+      get_bits_long (gb, 8);
+    } while (bsi->addbsil--);
+  }
+
+  bsi->nfchans = nfchans_tbl[bsi->acmod];
+  return 0;
+}
+
+static int bands[16] =
+{ 31, 35, 37, 39, 41, 42, 43, 44,
+  45, 45, 46, 46, 47, 47, 48, 48 };
+
+static const int diff_exps_M1[128] =
+  { -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+     25, 25, 25 };
+
+static const int diff_exps_M2[128] =
+  { -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+    -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+    -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+    -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+    -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+    25, 25, 25 };
+
+static const int diff_exps_M3[128] =
+  { -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2,
+    -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2,
+    -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2,
+    -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2,
+    -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2, -2, -1, 0, 1, 2,
+    25, 25, 25 };
+
+/* Decodes the grouped exponents (gexps) and stores them
+ * in decoded exponents (dexps).
+ */
+static int
+_decode_exponents (int expstr, int ngrps, uint8_t absexp, uint8_t * gexps, uint8_t * dexps)
+{
+  int i = 0, exp;
+  while (ngrps--) {
+    exp = gexps[i++];
+
+    absexp += diff_exps_M1[exp];
+    if (absexp > 24)
+      return -1;
+    if (expstr == AC3_EXPSTR_D45) {
+      *(dexps++) = absexp;
+      *(dexps++) = absexp;
+    }
+    else if (expstr == AC3_EXPSTR_D25)
+      *(dexps++) = absexp;
+    else
+      *(dexps++) = absexp;
+
+    absexp += diff_exps_M2[exp];
+    if (absexp > 24)
+      return -1;
+    if (expstr == AC3_EXPSTR_D45) {
+      *(dexps++) = absexp;
+      *(dexps++) = absexp;
+    }
+    else if (expstr == AC3_EXPSTR_D25)
+      *(dexps++) = absexp;
+    else
+      *(dexps++) = absexp;
+
+    absexp += diff_exps_M3[exp];
+    if (absexp > 24)
+      return -1;
+    if (expstr == AC3_EXPSTR_D45) {
+      *(dexps++) = absexp;
+      *(dexps++) = absexp;
+    }
+    else if (expstr == AC3_EXPSTR_D25)
+      *(dexps++) = absexp;
+    else
+      *(dexps++) = absexp;
+  }
+
+  return 0;
+}
+
+static int
+decode_exponents (AC3DecodeContext * ctx)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  int i;
+  uint8_t *exps;
+  uint8_t *dexps;
+
+  if (ab->flags & AC3_AB_CPLINU && ab->cplexpstr != AC3_EXPSTR_REUSE)
+    if (_decode_exponents (ab->cplexpstr, ab->ncplgrps, ab->cplabsexp,
+                           ab->cplexps, ab->dcplexps + ab->cplstrtmant))
+      return -1;
+  for (i = 0; i < ctx->bsi.nfchans; i++)
+    if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) {
+      exps = ab->exps[i];
+      dexps = ab->dexps[i];
+      if (_decode_exponents (ab->chexpstr[i], ab->nchgrps[i], exps[0], exps + 1, dexps + 1))
+        return -1;
+    }
+  if (ctx->bsi.flags & AC3_BSI_LFEON && ab->lfeexpstr != AC3_EXPSTR_REUSE)
+    if (_decode_exponents (ab->lfeexpstr, 2, ab->lfeexps[0], ab->lfeexps + 1, ab->dlfeexps))
+      return -1;
+  return 0;
+}
+
+static const int16_t slowdec[4] = { 0x0f, 0x11, 0x13, 0x15 }; /* slow decay table */
+static const int16_t fastdec[4] = { 0x3f, 0x53, 0x67, 0x7b }; /* fast decay table */
+static const int16_t slowgain[4] = { 0x540, 0x4d8, 0x478, 0x410 };   /* slow gain table */
+static const int16_t dbpbtab[4] = { 0x000, 0x700, 0x900, 0xb00 };    /* dB/bit table */
+
+static const int16_t floortab[8] =  /* floor table */
+{ 0x2f0, 0x2b0, 0x270, 0x230,
+  0x1f0, 0x170, 0x0f0, 0xf800 };
+
+static const int16_t fastgain[8] = /* fast gain table */
+{ 0x080, 0x100, 0x180, 0x200,
+  0x280, 0x300, 0x380, 0x400 };
+
+static const int16_t bndtab[50] = /* start band table */
+{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
+  27, 28, 31, 34, 37, 40, 43, 46, 49, 55, 61, 67, 73, 79, 85, 97, 109, 121, 133, 157, 181, 205, 229 };
+
+static const int16_t bndsz[50] = /* band size table */
+{ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 24, 24, 24, 24, 24 };
+
+static const int16_t masktab[256] = /* masking table */
+{  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+  25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34, 35,
+  35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36, 37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38, 39, 39,
+  39, 39, 39, 39, 40, 40, 40, 40, 40, 40, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 42, 42, 42,
+  42, 42, 42, 42, 42, 42, 42, 42, 42, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 44, 44, 44, 44,
+  44, 44, 44, 44, 44, 44, 44, 44, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
+  45, 45, 45, 45, 45, 45, 45, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
+  46, 46, 46, 46, 46, 46, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
+  47, 47, 47, 47, 47, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
+  48, 48, 48, 48, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49,
+  49, 49, 49, 0, 0, 0 };
+
+static const int16_t latab[256] = /* log addition table */
+{ 0x0040, 0x003f, 0x003e, 0x003d, 0x003c, 0x003b, 0x003a, 0x0039, 0x0038, 0x0037, 0x0036, 0x0035,
+  0x0034, 0x0034, 0x0033, 0x0032, 0x0031, 0x0030, 0x002f, 0x002f, 0x002e, 0x002d, 0x002c, 0x002c,
+  0x002b, 0x002a, 0x0029, 0x0029, 0x0028, 0x0027, 0x0026, 0x0026, 0x0025, 0x0024, 0x0024, 0x0023,
+  0x0023, 0x0022, 0x0021, 0x0021, 0x0020, 0x0020, 0x001f, 0x001e, 0x001e, 0x001d, 0x001d, 0x001c,
+  0x001c, 0x001b, 0x001b, 0x001a, 0x001a, 0x0019, 0x0019, 0x0018, 0x0018, 0x0017, 0x0017, 0x0016,
+  0x0016, 0x0015, 0x0015, 0x0015, 0x0014, 0x0014, 0x0013, 0x0013, 0x0013, 0x0012, 0x0012, 0x0012,
+  0x0011, 0x0011, 0x0011, 0x0010, 0x0010, 0x0010, 0x000f, 0x000f, 0x000f, 0x000e, 0x000e, 0x000e,
+  0x000d, 0x000d, 0x000d, 0x000d, 0x000c, 0x000c, 0x000c, 0x000c, 0x000b, 0x000b, 0x000b, 0x000b,
+  0x000a, 0x000a, 0x000a, 0x000a, 0x000a, 0x0009, 0x0009, 0x0009, 0x0009, 0x0009, 0x0008, 0x0008,
+  0x0008, 0x0008, 0x0008, 0x0008, 0x0007, 0x0007, 0x0007, 0x0007, 0x0007, 0x0007, 0x0006, 0x0006,
+  0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005,
+  0x0005, 0x0005, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004,
+  0x0004, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003,
+  0x0003, 0x0003, 0x0003, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002,
+  0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0001, 0x0001,
+  0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001,
+  0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001,
+  0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000 };
+
+static const int16_t hth[3][50] = /* hearing threshold table */
+{
+  {0x04d0, 0x04d0, 0x0440, 0x0400, 0x03e0, 0x03c0, 0x03b0, 0x03b0, 0x03a0, 0x03a0, 0x03a0, 0x03a0,
+   0x03a0, 0x0390, 0x0390, 0x0390, 0x0380, 0x0380, 0x0370, 0x0370, 0x0360, 0x0360, 0x0350, 0x0350,
+   0x0340, 0x0340, 0x0330, 0x0320, 0x0310, 0x0300, 0x02f0, 0x02f0, 0x02f0, 0x02f0, 0x0300, 0x0310,
+   0x0340, 0x0390, 0x03e0, 0x0420, 0x0460, 0x0490, 0x04a0, 0x0440, 0x0440, 0x0400, 0x0520, 0x0800,
+   0x0840, 0x0840},
+  {0x04f0, 0x04f0, 0x0460, 0x0410, 0x03e0, 0x03d0, 0x03c0, 0x03b0, 0x03b0, 0x03a0, 0x03a0, 0x03a0,
+   0x03a0, 0x03a0, 0x0390, 0x0390, 0x0390, 0x0380, 0x0380, 0x0380, 0x0370, 0x0370, 0x0360, 0x0360,
+   0x0350, 0x0350, 0x0340, 0x0340, 0x0320, 0x0310, 0x0300, 0x02f0, 0x02f0, 0x02f0, 0x02f0, 0x0300,
+   0x0320, 0x0350, 0x0390, 0x03e0, 0x0420, 0x0450, 0x04a0, 0x0490, 0x0460, 0x0440, 0x0480, 0x0630,
+   0x0840, 0x0840},
+  {0x0580, 0x0580, 0x04b0, 0x0450, 0x0420, 0x03f0, 0x03e0, 0x03d0, 0x03c0, 0x03b0, 0x03b0, 0x03b0,
+   0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x0390, 0x0390, 0x0390, 0x0390,
+   0x0380, 0x0380, 0x0380, 0x0370, 0x0360, 0x0350, 0x0340, 0x0330, 0x0320, 0x0310, 0x0300, 0x02f0,
+   0x02f0, 0x02f0, 0x0300, 0x0310, 0x0330, 0x0350, 0x03c0, 0x0410, 0x0470, 0x04a0, 0x0460, 0x0440,
+   0x0450, 0x04e0}
+};
+
+static const uint8_t baptab[64] = /* bit allocation pointer table */
+{ 0, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10,
+  10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15,
+  15, 15, 15, 15, 15, 15, 15, 15 };
+
+static inline int16_t
+logadd (int16_t a, int16_t b)
+{
+  int16_t c = a - b;
+  uint8_t address = FFMIN ((ABS (c) >> 1), 255);
+
+  return ((c >= 0) ? (a + latab[address]) : (b + latab[address]));
+}
+
+static inline int16_t
+calc_lowcomp (int16_t a, int16_t b0, int16_t b1, uint8_t bin)
+{
+  if (bin < 7) {
+    if ((b0 + 256) == b1)
+      a = 384;
+    else if (b0 > b1)
+      a = FFMAX (0, a - 64);
+  }
+  else if (bin < 20) {
+    if ((b0 + 256) == b1)
+      a = 320;
+    else if (b0 > b1)
+      a = FFMAX (0, a - 64);
+  }
+  else {
+    a = FFMAX (0, a - 128);
+  }
+
+  return a;
+}
+
+/* do the bit allocation for chnl.
+ * chnl = 0 to 4 - fbw channel
+ * chnl = 5 coupling channel
+ * chnl = 6 lfe channel
+ */
+static int
+_do_bit_allocation (AC3DecodeContext * ctx, int chnl)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  int16_t sdecay, fdecay, sgain, dbknee, floor;
+  int16_t lowcomp, fgain, snroffset, fastleak, slowleak;
+  int16_t psd[256], bndpsd[50], excite[50], mask[50], delta;
+  uint8_t start, end, bin, i, j, k, lastbin, bndstrt, bndend, begin, deltnseg, band, seg, address;
+  uint8_t fscod = ctx->sync_info.fscod;
+  uint8_t *exps, *deltoffst, *deltlen, *deltba;
+  uint8_t *baps;
+  int do_delta = 0;
+
+  /* initialization */
+  sdecay = slowdec[ab->sdcycod];
+  fdecay = fastdec[ab->fdcycod];
+  sgain = slowgain[ab->sgaincod];
+  dbknee = dbpbtab[ab->dbpbcod];
+  floor = dbpbtab[ab->floorcod];
+
+  if (chnl == 5) {
+    start = ab->cplstrtmant;
+    end = ab->cplendmant;
+    fgain = fastgain[ab->cplfgaincod];
+    snroffset = (((ab->csnroffst - 15) << 4) + ab->cplfsnroffst) << 2;
+    fastleak = (ab->cplfleak << 8) + 768;
+    slowleak = (ab->cplsleak << 8) + 768;
+    exps = ab->dcplexps;
+    baps = ab->cplbap;
+    if (ab->cpldeltbae == 0 || ab->cpldeltbae == 1) {
+      do_delta = 1;
+      deltnseg = ab->cpldeltnseg;
+      deltoffst = ab->cpldeltoffst;
+      deltlen = ab->cpldeltlen;
+      deltba = ab->cpldeltba;
+    }
+  }
+  else if (chnl == 6) {
+    start = 0;
+    end = 7;
+    lowcomp = 0;
+    fgain = fastgain[ab->lfefgaincod];
+    snroffset = (((ab->csnroffst - 15) << 4) + ab->lfefsnroffst) << 2;
+    exps = ab->dlfeexps;
+    baps = ab->lfebap;
+  }
+  else {
+    start = 0;
+    end = ab->endmant[chnl];
+    lowcomp = 0;
+    fgain = fastgain[ab->fgaincod[chnl]];
+    snroffset = (((ab->csnroffst - 15) << 4) + ab->fsnroffst[chnl]) << 2;
+    exps = ab->dexps[chnl];
+    baps = ab->bap[chnl];
+    if (ab->deltbae[chnl] == 0 || ab->deltbae[chnl] == 1) {
+      do_delta = 1;
+      deltnseg = ab->deltnseg[chnl];
+      deltoffst = ab->deltoffst[chnl];
+      deltlen = ab->deltlen[chnl];
+      deltba = ab->deltba[chnl];
+    }
+  }
+
+  for (bin = start; bin < end; bin++) /* exponent mapping into psd */
+    psd[bin] = (3072 - ((int16_t) (exps[bin] << 7)));
+
+  /* psd integration */
+  j = start;
+  k = masktab[start];
+  do {
+    lastbin = FFMIN (bndtab[k] + bndsz[k], end);
+    bndpsd[k] = psd[j];
+    j++;
+    for (i = j; i < lastbin; i++) {
+      bndpsd[k] = logadd (bndpsd[k], psd[j]);
+      j++;
+    }
+    k++;
+  } while (end > lastbin);
+
+  /* compute the excite function */
+  bndstrt = masktab[start];
+  bndend = masktab[end - 1] + 1;
+  if (bndstrt == 0) {
+    lowcomp = calc_lowcomp (lowcomp, bndpsd[0], bndpsd[1], 0);
+    excite[0] = bndpsd[0] - fgain - lowcomp;
+    lowcomp = calc_lowcomp (lowcomp, bndpsd[1], bndpsd[2], 1);
+    excite[1] = bndpsd[1] - fgain - lowcomp;
+    begin = 7;
+    for (bin = 2; bin < 7; bin++) {
+      if (bndend != 7 || bin != 6)
+        lowcomp = calc_lowcomp (lowcomp, bndpsd[bin], bndpsd[bin + 1], bin);
+      fastleak = bndpsd[bin] - fgain;
+      slowleak = bndpsd[bin] - sgain;
+      excite[bin] = fastleak - lowcomp;
+      if (bndend != 7 || bin != 6)
+        if (bndpsd[bin] <= bndpsd[bin + 1]) {
+          begin = bin + 1;
+          break;
+        }
+    }
+    for (bin = begin; bin < (FFMIN (bndend, 22)); bin++) {
+      if (bndend != 7 || bin != 6)
+        lowcomp = calc_lowcomp (lowcomp, bndpsd[bin], bndpsd[bin + 1], bin);
+      fastleak -= fdecay;
+      fastleak = FFMAX (fastleak, bndpsd[bin] - fgain);
+      slowleak -= sdecay;
+      slowleak = FFMAX (slowleak, bndpsd[bin] - sgain);
+      excite[bin] = FFMAX (fastleak - lowcomp, slowleak);
+    }
+    begin = 22;
+  }
+  else {
+    begin = bndstrt;
+  }
+  for (bin = begin; bin < bndend; bin++) {
+    fastleak -= fdecay;
+    fastleak = FFMAX (fastleak, bndpsd[bin] - fgain);
+    slowleak -= sdecay;
+    slowleak = FFMAX (slowleak, bndpsd[bin] - sgain);
+    excite[bin] = FFMAX (fastleak, slowleak);
+  }
+
+  /* compute the masking curve */
+  for (bin = bndstrt; bin < bndend; bin++) {
+    if (bndpsd[bin] < dbknee)
+      excite[bin] += ((dbknee - bndpsd[bin]) >> 2);
+    mask[bin] = FFMAX (excite[bin], hth[fscod][bin]);
+  }
+
+  /* apply the delta bit allocation */
+  if (do_delta) {
+    band = 0;
+    for (seg = 0; seg < deltnseg + 1; seg++) {
+      band += deltoffst[seg];
+      if (deltba[seg] >= 4)
+        delta = (deltba[seg] - 3) << 7;
+      else
+        delta = (deltba[seg] - 4) << 7;
+      for (k = 0; k < deltlen[seg]; k++) {
+        mask[band] += delta;
+        band++;
+      }
+    }
+  }
+
+  /*compute the bit allocation */
+  i = start;
+  j = masktab[start];
+  do {
+    lastbin = FFMIN (bndtab[j] + bndsz[j], end);
+    mask[j] -= snroffset;
+    mask[j] -= floor;
+    if (mask[j] < 0)
+      mask[j] = 0;
+    mask[j] &= 0x1fe0;
+    mask[j] += floor;
+    for (k = i; k < lastbin; k++) {
+      address = (psd[i] - mask[j]) >> 5;
+      address = FFMIN (63, (FFMAX (0, address)));
+      baps[i] = baptab[address];
+      i++;
+    }
+    j++;
+  } while (end > lastbin);
+
+  return 0;
+}
+
+static int
+do_bit_allocation (AC3DecodeContext * ctx, int flags)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  int i, snroffst = 0;
+
+  if (!flags) /* bit allocation is not required */
+    return 0;
+
+  if (ab->flags & AC3_AB_SNROFFSTE) { /* check whether snroffsts are zero */
+    snroffst += ab->csnroffst;
+    if (ab->flags & AC3_AB_CPLINU)
+      snroffst += ab->cplfsnroffst;
+    for (i = 0; i < ctx->bsi.nfchans; i++)
+      snroffst += ab->fsnroffst[i];
+    if (ctx->bsi.flags & AC3_BSI_LFEON)
+      snroffst += ab->lfefsnroffst;
+    if (!snroffst) {
+      memset (ab->cplbap, 0, sizeof (ab->cplbap));
+      for (i = 0; i < ctx->bsi.nfchans; i++)
+        memset (ab->bap[i], 0, sizeof (ab->bap[i]));
+      memset (ab->lfebap, 0, sizeof (ab->lfebap));
+
+      return 0;
+    }
+  }
+
+  /* perform bit allocation */
+  if ((ab->flags & AC3_AB_CPLINU) && (flags & 64))
+    if (_do_bit_allocation (ctx, 5))
+      return -1;
+  for (i = 0; i < ctx->bsi.nfchans; i++)
+    if (flags & (1 << i))
+      if (_do_bit_allocation (ctx, i))
+        return -1;
+  if ((ctx->bsi.flags & AC3_BSI_LFEON) && (flags & 32))
+    if (_do_bit_allocation (ctx, 6))
+      return -1;
+
+  return 0;
+}
+
+/* table for exponent to scale_factor mapping
+ * scale_factor[i] = 2 ^ -(i + 15)
+ */
+static const float scale_factors[25] = {
+  0.000030517578125000000000000000000000000,
+  0.000015258789062500000000000000000000000,
+  0.000007629394531250000000000000000000000,
+  0.000003814697265625000000000000000000000,
+  0.000001907348632812500000000000000000000,
+  0.000000953674316406250000000000000000000,
+  0.000000476837158203125000000000000000000,
+  0.000000238418579101562500000000000000000,
+  0.000000119209289550781250000000000000000,
+  0.000000059604644775390625000000000000000,
+  0.000000029802322387695312500000000000000,
+  0.000000014901161193847656250000000000000,
+  0.000000007450580596923828125000000000000,
+  0.000000003725290298461914062500000000000,
+  0.000000001862645149230957031250000000000,
+  0.000000000931322574615478515625000000000,
+  0.000000000465661287307739257812500000000,
+  0.000000000232830643653869628906250000000,
+  0.000000000116415321826934814453125000000,
+  0.000000000058207660913467407226562500000,
+  0.000000000029103830456733703613281250000,
+  0.000000000014551915228366851806640625000,
+  0.000000000007275957614183425903320312500,
+  0.000000000003637978807091712951660156250,
+  0.000000000001818989403545856475830078125
+};
+
+static const int16_t l3_q_tab[3] = { /* 3-level quantization table */
+  (-2 << 15) / 3, 0, (2 << 15) / 3
+};
+
+static const int16_t l5_q_tab[5] = { /* 5-level quantization table */
+  (-4 << 15) / 5, (-2 << 15) / 5, 0, (2 << 15) / 5, (4 << 15) / 5
+};
+
+static const int16_t l7_q_tab[7] = { /* 7-level quantization table */
+  (-6 << 15) / 7, (-4 << 15) / 7, (-2 << 15) / 7, 0,
+  (2 << 15) / 7, (4 << 15) / 7, (6 << 15) / 7
+};
+
+static const int16_t l11_q_tab[11] = { /* 11-level quantization table */
+  (-10 << 15) / 11, (-8 << 15) / 11, (-6 << 15) / 11, (-4 << 15) / 11, (-2 << 15) / 11, 0,
+  (2 << 15) / 11, (4 << 15) / 11, (6 << 15) / 11, (8 << 15) / 11, (10 << 15) / 11
+};
+
+static const int16_t l15_q_tab[15] = { /* 15-level quantization table */
+  (-14 << 15) / 15, (-12 << 15) / 15, (-10 << 15) / 15, (-8 << 15) / 15,
+  (-6 << 15) / 15, (-4 << 15) / 15, (-2 << 15) / 15, 0,
+  (2 << 15) / 15, (4 << 15) / 15, (6 << 15) / 15, (8 << 15) / 15,
+  (10 << 15) / 15, (12 << 15) / 15, (14 << 15) / 15
+};
+
+static const uint8_t qntztab[16] = { 0, 5, 7, 3, 7, 4, 5, 6, 7, 8, 9, 10, 12, 12, 14, 16 };
+
+static inline float
+to_float (uint8_t exp, int16_t mantissa)
+{
+  return ((float) (mantissa * scale_factors[exp]));
+}
+
+typedef struct
+{ /* grouped mantissas for 3-level 5-leve and 11-level quantization */
+  uint8_t gcodes[3];
+  uint8_t gcptr;
+} mant_group;
+
+/* Get the transform coefficients for particular channel */
+static int
+_get_transform_coeffs (uint8_t * exps, uint8_t * bap, float *samples,
+                       int start, int end, int dith_flag, GetBitContext * gb)
+{
+  int16_t mantissa;
+  int i;
+  int gcode;
+  mant_group l3_grp, l5_grp, l11_grp;
+
+  for (i = 0; i < 3; i++)
+    l3_grp.gcodes[i] = l5_grp.gcodes[i] = l11_grp.gcodes[i] = -1;
+  l3_grp.gcptr = l5_grp.gcptr = 3;
+  l11_grp.gcptr = 2;
+
+  i = 0;
+  while (i < start)
+    samples[i++] = 0;
+
+  for (i = start; i < end; i++) {
+    switch (bap[i]) {
+    case 0:
+      if (!dith_flag)
+        mantissa = 0;
+      else
+        mantissa = gen_dither ();
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+
+    case 1:
+      if (l3_grp.gcptr > 2) {
+        gcode = get_bits_long (gb, qntztab[1]);
+        if (gcode > 26)
+          return -1;
+        l3_grp.gcodes[0] = gcode / 9;
+        l3_grp.gcodes[1] = (gcode % 9) / 3;
+        l3_grp.gcodes[2] = (gcode % 9) % 3;
+        l3_grp.gcptr = 0;
+      }
+      mantissa = l3_q_tab[l3_grp.gcodes[l3_grp.gcptr++]];
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+
+    case 2:
+      if (l5_grp.gcptr > 2) {
+        gcode = get_bits_long (gb, qntztab[2]);
+        if (gcode > 124)
+          return -1;
+        l5_grp.gcodes[0] = gcode / 25;
+        l5_grp.gcodes[1] = (gcode % 25) / 5;
+        l5_grp.gcodes[2] = (gcode % 25) % 5;
+        l5_grp.gcptr = 0;
+      }
+      mantissa = l5_q_tab[l5_grp.gcodes[l5_grp.gcptr++]];
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+
+    case 3:
+      mantissa = get_bits_long (gb, qntztab[3]);
+      if (mantissa > 6)
+        return -1;
+      mantissa = l7_q_tab[mantissa];
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+
+    case 4:
+      if (l11_grp.gcptr > 1) {
+        gcode = get_bits_long (gb, qntztab[4]);
+        if (gcode > 120)
+          return -1;
+        l11_grp.gcodes[0] = gcode / 11;
+        l11_grp.gcodes[1] = gcode % 11;
+      }
+      mantissa = l11_q_tab[l11_grp.gcodes[l11_grp.gcptr++]];
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+
+    case 5:
+      mantissa = get_bits_long (gb, qntztab[5]);
+      if (mantissa > 14)
+        return -1;
+      mantissa = l15_q_tab[mantissa];
+      break;
+
+    default:
+      mantissa = get_bits_long (gb, qntztab[bap[i]]) << (16 - qntztab[bap[i]]);
+      samples[i] = to_float (exps[i], mantissa);
+      break;
+    }
+  }
+
+  i = end;
+  while (i < 256)
+    samples[i++] = 0;
+
+  return 0;
+}
+
+static int
+uncouple_channels (AC3DecodeContext * ctx)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  int ch, sbnd, bin;
+  int index;
+  float (*samples)[256];
+  int16_t mantissa;
+
+  samples = (float (*)[256]) (ab->ab_samples);
+  samples += (ctx->bsi.flags & AC3_BSI_LFEON) ? 256 : 0;
+
+  /* uncouple channels */
+  for (ch = 0; ch < ctx->bsi.nfchans; ch++)
+    if (ab->chincpl & (1 << ch))
+      for (sbnd = ab->cplbegf; sbnd < 3 + ab->cplendf; sbnd++)
+        for (bin = 0; bin < 12; bin++) {
+          index = sbnd * 12 + bin + 37;
+          samples[ch][index] = ab->cplcoeffs[index] * ab->cplco[ch][sbnd] * 8;
+        }
+
+  /* generate dither if required */
+  for (ch = 0; ch < ctx->bsi.nfchans; ch++)
+    if ((ab->chincpl & (1 << ch)) && (ab->dithflag & (1 << ch)))
+      for (index = 0; index < ab->endmant[ch]; index++)
+        if (!ab->bap[ch][index]) {
+          mantissa = gen_dither ();
+          samples[ch][index] = to_float (ab->dexps[ch][index], mantissa);
+        }
+
+  return 0;
+}
+
+static int
+get_transform_coeffs (AC3DecodeContext * ctx)
+{
+  int i;
+  ac3_audio_block *ab = &ctx->audio_block;
+  float *samples = ab->ab_samples;
+  int got_cplchan = 0;
+  int dithflag = 0;
+
+  samples += (ctx->bsi.flags & AC3_BSI_LFEON) ? 256 : 0;
+  for (i = 0; i < ctx->bsi.nfchans; i++) {
+    if ((ab->flags & AC3_AB_CPLINU) && (ab->chincpl & (1 << i)))
+      dithflag = 0; /* don't generate dither until channels are decoupled */
+    else
+      dithflag = ab->dithflag & (1 << i);
+    /* transform coefficients for individual channel */
+    if (_get_transform_coeffs (ab->dexps[i], ab->bap[i], samples + (i * 256),
+                               0, ab->endmant[i], dithflag, &ctx->gb))
+      return -1;
+    /* tranform coefficients for coupling channels */
+    if ((ab->flags & AC3_AB_CPLINU) && (ab->chincpl & (1 << i)) && !got_cplchan) {
+      if (_get_transform_coeffs (ab->dcplexps, ab->cplbap, ab->cplcoeffs,
+                                 ab->cplstrtmant, ab->cplendmant, 0, &ctx->gb))
+        return -1;
+      got_cplchan = 1;
+    }
+  }
+
+  /* uncouple the channels from the coupling channel */
+  if (ab->flags & AC3_AB_CPLINU)
+    if (uncouple_channels (ctx))
+      return -1;
+
+  return 0;
+}
+
+/* generate coupling co-ordinates for each coupling subband
+ * from coupling co-ordinates of each band and coupling band
+ * structure information
+ */
+static int
+generate_coupling_coordinates (AC3DecodeContext * ctx)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  uint8_t exp, mstrcplco;
+  int16_t mant;
+  uint32_t cplbndstrc = (1 << ab->ncplsubnd) >> 1;
+  int ch, bnd, sbnd;
+  float cplco;
+
+  if (ab->cplcoe)
+    for (ch = 0; ch < ctx->bsi.nfchans; ch++)
+      if (ab->cplcoe & (1 << ch)) {
+        mstrcplco = 3 * ab->mstrcplco[ch];
+        sbnd = ab->cplbegf;
+        for (bnd = 0; bnd < ab->ncplbnd; bnd++) {
+          exp = ab->cplcoexp[ch][bnd];
+          if (exp == 15)
+            mant = ab->cplcomant[ch][bnd] <<= 14;
+          else
+            mant = (ab->cplcomant[ch][bnd] | 0x10) << 13;
+          cplco = to_float (exp + mstrcplco, mant);
+          if (ctx->bsi.acmod == 0x02 && (ab->flags & AC3_AB_PHSFLGINU) && ch == 1
+              && (ab->phsflg & (1 << bnd)))
+            cplco = -cplco; /* invert the right channel */
+          ab->cplco[ch][sbnd++] = cplco;
+          while (cplbndstrc & ab->cplbndstrc) {
+            cplbndstrc >>= 1;
+            ab->cplco[ch][sbnd++] = cplco;
+          }
+          cplbndstrc >>= 1;
+        }
+      }
+
+  return 0;
+}
+
+static int
+ac3_parse_audio_block (AC3DecodeContext * ctx, int index)
+{
+  ac3_audio_block *ab = &ctx->audio_block;
+  int nfchans = ctx->bsi.nfchans;
+  int acmod = ctx->bsi.acmod;
+  int i, bnd, rbnd, grp, seg;
+  GetBitContext *gb = &ctx->gb;
+  uint32_t *flags = &ab->flags;
+  int bit_alloc_flags = 0;
+
+  *flags = 0;
+  ab->blksw = 0;
+  for (i = 0; i < nfchans; i++) /*block switch flag */
+    ab->blksw |= get_bits_long (gb, 1) << i;
+  ab->dithflag = 0;
+  for (i = 0; i < nfchans; i++) /* dithering flag */
+    ab->dithflag |= get_bits_long (gb, 1) << i;
+  if (get_bits_long (gb, 1)) { /* dynamic range */
+    *flags |= AC3_AB_DYNRNGE;
+    ab->dynrng = get_bits_long (gb, 8);
+  }
+  if (acmod == 0x00) { /* dynamic range 1+1 mode */
+    if (get_bits_long (gb, 1)) {
+      *flags |= AC3_AB_DYNRNG2E;
+      ab->dynrng2 = get_bits_long (gb, 8);
+    }
+  }
+  ab->chincpl = 0;
+  if (get_bits_long (gb, 1)) { /* coupling strategy */
+    *flags |= AC3_AB_CPLSTRE;
+    ab->cplbndstrc = 0;
+    if (get_bits_long (gb, 1)) { /* coupling in use */
+      *flags |= AC3_AB_CPLINU;
+    for (i = 0; i < nfchans; i++)
+      ab->chincpl |= get_bits_long (gb, 1) << i;
+    if (acmod == 0x02)
+      if (get_bits_long (gb, 1)) /* phase flag in use */
+        *flags |= AC3_AB_PHSFLGINU;
+    ab->cplbegf = get_bits_long (gb, 4);
+    ab->cplendf = get_bits_long (gb, 4);
+    if ((ab->ncplsubnd = 3 + ab->cplendf - ab->cplbegf) < 0)
+      return -1;
+    ab->ncplbnd = ab->ncplsubnd;
+    for (i = 0; i < ab->ncplsubnd - 1; i++) /* coupling band structure */
+      if (get_bits_long (gb, 1)) {
+        ab->cplbndstrc |= 1 << i;
+        ab->ncplbnd--;
+      }
+    }
+  }
+  if (*flags & AC3_AB_CPLINU) {
+    ab->cplcoe = 0;
+    for (i = 0; i < nfchans; i++)
+      if (ab->chincpl & (1 << i))
+        if (get_bits_long (gb, 1)) { /* coupling co-ordinates */
+          ab->cplcoe |= 1 << i;
+          ab->mstrcplco[i] = get_bits_long (gb, 2);
+          for (bnd = 0; bnd < ab->ncplbnd; bnd++) {
+            ab->cplcoexp[i][bnd] = get_bits_long (gb, 4);
+            ab->cplcomant[i][bnd] = get_bits_long (gb, 4);
+          }
+        }
+  }
+  ab->phsflg = 0;
+  if ((acmod == 0x02) && (*flags & AC3_AB_PHSFLGINU) && (ab->cplcoe & 1 || ab->cplcoe & (1 << 1))) {
+    for (bnd = 0; bnd < ab->ncplbnd; bnd++)
+      if (get_bits_long (gb, 1))
+        ab->phsflg |= 1 << bnd;
+  }
+  generate_coupling_coordinates (ctx);
+  ab->rematflg = 0;
+  if (acmod == 0x02) /* rematrixing */
+    if (get_bits_long (gb, 1)) {
+      *flags |= AC3_AB_REMATSTR;
+      if (ab->cplbegf > 2 || !(*flags & AC3_AB_CPLINU))
+        for (rbnd = 0; rbnd < 4; rbnd++)
+          ab->rematflg |= get_bits_long (gb, 1) << bnd;
+      else if (ab->cplbegf > 0 && ab->cplbegf <= 2 && *flags & AC3_AB_CPLINU)
+        for (rbnd = 0; rbnd < 3; rbnd++)
+          ab->rematflg |= get_bits_long (gb, 1) << bnd;
+      else if (!(ab->cplbegf) && *flags & AC3_AB_CPLINU)
+        for (rbnd = 0; rbnd < 2; rbnd++)
+          ab->rematflg |= get_bits_long (gb, 1) << bnd;
+    }
+  if (*flags & AC3_AB_CPLINU) /* coupling exponent strategy */
+    ab->cplexpstr = get_bits_long (gb, 2);
+  for (i = 0; i < nfchans; i++) /* channel exponent strategy */
+    ab->chexpstr[i] = get_bits_long (gb, 2);
+  if (ctx->bsi.flags & AC3_BSI_LFEON) /* lfe exponent strategy */
+    ab->lfeexpstr = get_bits_long (gb, 1);
+  for (i = 0; i < nfchans; i++) /* channel bandwidth code */
+    if (ab->chexpstr[i] != AC3_EXPSTR_REUSE)
+      if (!(ab->chincpl & (1 << i))) {
+        ab->chbwcod[i] = get_bits_long (gb, 6);
+        if (ab->chbwcod[i] > 60)
+          return -1;
+      }
+  if (*flags & AC3_AB_CPLINU)
+    if (ab->cplexpstr != AC3_EXPSTR_REUSE) {/* coupling exponents */
+      bit_alloc_flags |= 64;
+      ab->cplabsexp = get_bits_long (gb, 4) << 1;
+      ab->cplstrtmant = (ab->cplbegf * 12) + 37;
+      ab->cplendmant = ((ab->cplendmant + 3) * 12) + 37;
+      ab->ncplgrps = (ab->cplendmant - ab->cplstrtmant) / (3 << (ab->cplexpstr - 1));
+      for (grp = 0; grp < ab->ncplgrps; grp++)
+        ab->cplexps[grp] = get_bits_long (gb, 7);
+    }
+  for (i = 0; i < nfchans; i++) /* fbw channel exponents */
+    if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) {
+      bit_alloc_flags |= 1 << i;
+      if (ab->chincpl & (1 << i))
+        ab->endmant[i] = (ab->cplbegf * 12) + 37;
+      else
+        ab->endmant[i] = ((ab->chbwcod[i] + 3) * 12) + 37;
+      ab->nchgrps[i] =
+        (ab->endmant[i] + (3 << (ab->chexpstr[i] - 1)) - 4) / (3 << (ab->chexpstr[i] - 1));
+      ab->exps[i][0] = ab->dexps[i][0] = get_bits_long (gb, 4);
+      for (grp = 1; grp <= ab->nchgrps[i]; grp++)
+        ab->exps[i][grp] = get_bits_long (gb, 7);
+      ab->gainrng[i] = get_bits_long (gb, 2);
+    }
+  if (ctx->bsi.flags & AC3_BSI_LFEON) /* lfe exponents */
+    if (ab->lfeexpstr != AC3_EXPSTR_REUSE) {
+      bit_alloc_flags |= 32;
+      ab->lfeexps[0] = ab->dlfeexps[0] = get_bits_long (gb, 4);
+      ab->lfeexps[1] = get_bits_long (gb, 7);
+      ab->lfeexps[2] = get_bits_long (gb, 7);
+    }
+  if (decode_exponents (ctx)) /* decode the exponents for this block */
+    return -1;
+  if (get_bits_long (gb, 1)) { /* bit allocation information */
+    *flags |= AC3_AB_BAIE;
+    bit_alloc_flags |= 127;
+    ab->sdcycod = get_bits_long (gb, 2);
+    ab->fdcycod = get_bits_long (gb, 2);
+    ab->sgaincod = get_bits_long (gb, 2);
+    ab->dbpbcod = get_bits_long (gb, 2);
+    ab->floorcod = get_bits_long (gb, 3);
+  }
+  if (get_bits_long (gb, 1)) { /* snroffset */
+    *flags |= AC3_AB_SNROFFSTE;
+    bit_alloc_flags |= 127;
+    ab->csnroffst = get_bits_long (gb, 6);
+    if (*flags & AC3_AB_CPLINU) { /* couling fine snr offset and fast gain code */
+      ab->cplfsnroffst = get_bits_long (gb, 4);
+      ab->cplfgaincod = get_bits_long (gb, 3);
+    }
+    for (i = 0; i < nfchans; i++) { /* channel fine snr offset and fast gain code */
+      ab->fsnroffst[i] = get_bits_long (gb, 4);
+      ab->fgaincod[i] = get_bits_long (gb, 3);
+    }
+    if (ctx->bsi.flags & AC3_BSI_LFEON) { /* lfe fine snr offset and fast gain code */
+      ab->lfefsnroffst = get_bits_long (gb, 4);
+      ab->lfefgaincod = get_bits_long (gb, 3);
+    }
+  }
+  if (*flags & AC3_AB_CPLINU)
+    if (get_bits_long (gb, 1)) { /* coupling leak information */
+      bit_alloc_flags |= 64;
+      *flags |= AC3_AB_CPLLEAKE;
+      ab->cplfleak = get_bits_long (gb, 3);
+      ab->cplsleak = get_bits_long (gb, 3);
+    }
+  if (get_bits_long (gb, 1)) { /* delta bit allocation information */
+    *flags |= AC3_AB_DELTBAIE;
+    bit_alloc_flags |= 127;
+    if (*flags & AC3_AB_CPLINU) {
+      ab->cpldeltbae = get_bits_long (gb, 2);
+      if (ab->cpldeltbae == AC3_DBASTR_RESERVED)
+        return -1;
+    }
+    for (i = 0; i < nfchans; i++) {
+      ab->deltbae[i] = get_bits_long (gb, 2);
+      if (ab->deltbae[i] == AC3_DBASTR_RESERVED)
+        return -1;
+    }
+    if (*flags & AC3_AB_CPLINU)
+      if (ab->cpldeltbae == AC3_DBASTR_NEW) { /*coupling delta offset, len and bit allocation */
+    ab->cpldeltnseg = get_bits_long (gb, 3);
+    for (seg = 0; seg <= ab->cpldeltnseg; seg++) {
+      ab->cpldeltoffst[seg] = get_bits_long (gb, 5);
+      ab->cpldeltlen[seg] = get_bits_long (gb, 4);
+      ab->cpldeltba[seg] = get_bits_long (gb, 3);
+    }
+      }
+    for (i = 0; i < nfchans; i++)
+      if (ab->deltbae[i] == AC3_DBASTR_NEW) {/*channel delta offset, len and bit allocation */
+    ab->deltnseg[i] = get_bits_long (gb, 3);
+    for (seg = 0; seg <= ab->deltnseg[i]; seg++) {
+      ab->deltoffst[i][seg] = get_bits_long (gb, 5);
+      ab->deltlen[i][seg] = get_bits_long (gb, 4);
+      ab->deltba[i][seg] = get_bits_long (gb, 3);
+    }
+      }
+  }
+  if (do_bit_allocation (ctx, bit_alloc_flags)) /* perform the bit allocation */
+    return -1;
+  if (get_bits_long (gb, 1)) { /* unused dummy data */
+    *flags |= AC3_AB_SKIPLE;
+    ab->skipl = get_bits_long (gb, 9);
+    while (ab->skipl) {
+      get_bits_long (gb, 8);
+      ab->skipl--;
+    }
+  }
+  /* point ab_samples to the right place within smaples */
+  if (!index)
+    ab->ab_samples = ctx->samples;
+  else {
+    ab->ab_samples = ctx->samples + (i * nfchans * 256);
+    ab->ab_samples += ((ctx->bsi.flags & AC3_BSI_LFEON) ? 256 : 0);
+  }
+  /* unpack the transform coefficients
+   * this also uncouples channels if coupling is in use.
+   */
+  if (get_transform_coeffs (ctx))
+    return -1;
+
+  return 0;
+}
+
+
+static int
+ac3_decode_frame (AVCodecContext * avctx, void *data, int *data_size, uint8_t * buf, int buf_size)
+{
+  AC3DecodeContext *ctx = avctx->priv_data;
+  int frame_start;
+  int i;
+
+  //Synchronize the frame.
+  frame_start = ac3_synchronize (buf, buf_size);
+  if (frame_start == -1) {
+    *data_size = 0;
+    return -1;
+  }
+
+  //Initialize the GetBitContext with the start of valid AC3 Frame.
+  init_get_bits (&(ctx->gb), buf + frame_start, (buf_size - frame_start) * 8);
+
+  //Parse the syncinfo.
+  //If 'fscod' is not valid the decoder shall mute as per the standard.
+  if (ac3_parse_sync_info (ctx)) {
+    *data_size = 0;
+    return -1;
+  }
+
+  //Check for the errors.
+  /*if (ac3_error_check(ctx))
+     {
+     *data_size = 0;
+     return -1;
+     } */
+
+  //Parse the BSI.
+  //If 'bsid' is not valid decoder shall not decode the audio as per the standard.
+  if (ac3_parse_bsi (ctx)) {
+    *data_size = 0;
+    return -1;
+  }
+
+  //Parse the Audio Blocks.
+  for (i = 0; i < 6; i++)
+    if (ac3_parse_audio_block (ctx, i)) {
+      *data_size = 0;
+      return -1;
+    }
+
+  return 0;
+}