From cc2160de5cc05dc3aa77f3a34358e66f6193c8c9 Mon Sep 17 00:00:00 2001
From: Michał Cichoń <michcic@gmail.com>
Date: Tue, 26 Jun 2012 20:35:30 +0200
Subject: Add support for AAC.

---
 faad2/src/libfaad/is.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 faad2/src/libfaad/is.c

(limited to 'faad2/src/libfaad/is.c')

diff --git a/faad2/src/libfaad/is.c b/faad2/src/libfaad/is.c
new file mode 100644
index 0000000..e6186a6
--- /dev/null
+++ b/faad2/src/libfaad/is.c
@@ -0,0 +1,109 @@
+/*
+** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
+** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+**
+** Any non-GPL usage of this software or parts of this software is strictly
+** forbidden.
+**
+** The "appropriate copyright message" mentioned in section 2c of the GPLv2
+** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
+**
+** Commercial non-GPL licensing of this software is possible.
+** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
+**
+** $Id: is.c,v 1.28 2007/11/01 12:33:31 menno Exp $
+**/
+
+#include "common.h"
+#include "structs.h"
+
+#include "syntax.h"
+#include "is.h"
+
+#ifdef FIXED_POINT
+static real_t pow05_table[] = {
+    COEF_CONST(1.68179283050743), /* 0.5^(-3/4) */
+    COEF_CONST(1.41421356237310), /* 0.5^(-2/4) */
+    COEF_CONST(1.18920711500272), /* 0.5^(-1/4) */
+    COEF_CONST(1.0),              /* 0.5^( 0/4) */
+    COEF_CONST(0.84089641525371), /* 0.5^(+1/4) */
+    COEF_CONST(0.70710678118655), /* 0.5^(+2/4) */
+    COEF_CONST(0.59460355750136)  /* 0.5^(+3/4) */
+};
+#endif
+
+void is_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
+               uint16_t frame_len)
+{
+    uint8_t g, sfb, b;
+    uint16_t i;
+#ifndef FIXED_POINT
+    real_t scale;
+#else
+    int32_t exp, frac;
+#endif
+
+    uint16_t nshort = frame_len/8;
+    uint8_t group = 0;
+
+    for (g = 0; g < icsr->num_window_groups; g++)
+    {
+        /* Do intensity stereo decoding */
+        for (b = 0; b < icsr->window_group_length[g]; b++)
+        {
+            for (sfb = 0; sfb < icsr->max_sfb; sfb++)
+            {
+                if (is_intensity(icsr, g, sfb))
+                {
+#ifdef MAIN_DEC
+                    /* For scalefactor bands coded in intensity stereo the
+                       corresponding predictors in the right channel are
+                       switched to "off".
+                     */
+                    ics->pred.prediction_used[sfb] = 0;
+                    icsr->pred.prediction_used[sfb] = 0;
+#endif
+
+#ifndef FIXED_POINT
+                    scale = (real_t)pow(0.5, (0.25*icsr->scale_factors[g][sfb]));
+#else
+                    exp = icsr->scale_factors[g][sfb] >> 2;
+                    frac = icsr->scale_factors[g][sfb] & 3;
+#endif
+
+                    /* Scale from left to right channel,
+                       do not touch left channel */
+                    for (i = icsr->swb_offset[sfb]; i < min(icsr->swb_offset[sfb+1], ics->swb_offset_max); i++)
+                    {
+#ifndef FIXED_POINT
+                        r_spec[(group*nshort)+i] = MUL_R(l_spec[(group*nshort)+i], scale);
+#else
+                        if (exp < 0)
+                            r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] << -exp;
+                        else
+                            r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] >> exp;
+                        r_spec[(group*nshort)+i] = MUL_C(r_spec[(group*nshort)+i], pow05_table[frac + 3]);
+#endif
+                        if (is_intensity(icsr, g, sfb) != invert_intensity(ics, g, sfb))
+                            r_spec[(group*nshort)+i] = -r_spec[(group*nshort)+i];
+                    }
+                }
+            }
+            group++;
+        }
+    }
+}
-- 
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