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+/* -----------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
+Forschung e.V. All rights reserved.
+
+ 1. INTRODUCTION
+The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
+that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
+scheme for digital audio. This FDK AAC Codec software is intended to be used on
+a wide variety of Android devices.
+
+AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
+general perceptual audio codecs. AAC-ELD is considered the best-performing
+full-bandwidth communications codec by independent studies and is widely
+deployed. AAC has been standardized by ISO and IEC as part of the MPEG
+specifications.
+
+Patent licenses for necessary patent claims for the FDK AAC Codec (including
+those of Fraunhofer) may be obtained through Via Licensing
+(www.vialicensing.com) or through the respective patent owners individually for
+the purpose of encoding or decoding bit streams in products that are compliant
+with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
+Android devices already license these patent claims through Via Licensing or
+directly from the patent owners, and therefore FDK AAC Codec software may
+already be covered under those patent licenses when it is used for those
+licensed purposes only.
+
+Commercially-licensed AAC software libraries, including floating-point versions
+with enhanced sound quality, are also available from Fraunhofer. Users are
+encouraged to check the Fraunhofer website for additional applications
+information and documentation.
+
+2. COPYRIGHT LICENSE
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted without payment of copyright license fees provided that you
+satisfy the following conditions:
+
+You must retain the complete text of this software license in redistributions of
+the FDK AAC Codec or your modifications thereto in source code form.
+
+You must retain the complete text of this software license in the documentation
+and/or other materials provided with redistributions of the FDK AAC Codec or
+your modifications thereto in binary form. You must make available free of
+charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived
+from this library without prior written permission.
+
+You may not charge copyright license fees for anyone to use, copy or distribute
+the FDK AAC Codec software or your modifications thereto.
+
+Your modified versions of the FDK AAC Codec must carry prominent notices stating
+that you changed the software and the date of any change. For modified versions
+of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
+must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
+AAC Codec Library for Android."
+
+3. NO PATENT LICENSE
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
+limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
+Fraunhofer provides no warranty of patent non-infringement with respect to this
+software.
+
+You may use this FDK AAC Codec software or modifications thereto only for
+purposes that are authorized by appropriate patent licenses.
+
+4. DISCLAIMER
+
+This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
+holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
+including but not limited to the implied warranties of merchantability and
+fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
+or consequential damages, including but not limited to procurement of substitute
+goods or services; loss of use, data, or profits, or business interruption,
+however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of
+this software, even if advised of the possibility of such damage.
+
+5. CONTACT INFORMATION
+
+Fraunhofer Institute for Integrated Circuits IIS
+Attention: Audio and Multimedia Departments - FDK AAC LL
+Am Wolfsmantel 33
+91058 Erlangen, Germany
+
+www.iis.fraunhofer.de/amm
+amm-info@iis.fraunhofer.de
+----------------------------------------------------------------------------- */
+
+/**************************** SBR decoder library ******************************
+
+ Author(s): Oliver Moser, Manuel Jander, Matthias Hildenbrand
+
+ Description: QMF frequency pre-whitening for SBR.
+ In the documentation the terms "scale factor" and "exponent"
+ mean the same. Variables containing such information have
+ the suffix "_sf".
+
+*******************************************************************************/
+
+#include "HFgen_preFlat.h"
+
+#define POLY_ORDER 3
+#define MAXLOWBANDS 32
+#define LOG10FAC 0.752574989159953f /* == 10/log2(10) * 2^-2 */
+#define LOG10FAC_INV 0.664385618977472f /* == log2(10)/20 * 2^2 */
+
+#define FIXP_CHB FIXP_SGL /* STB sinus Tab used in transformation */
+#define CHC(a) (FX_DBL2FXCONST_SGL(a))
+#define FX_CHB2FX_DBL(a) FX_SGL2FX_DBL(a)
+
+typedef struct backsubst_data {
+ FIXP_CHB Lnorm1d[3]; /*!< Normalized L matrix */
+ SCHAR Lnorm1d_sf[3];
+ FIXP_CHB Lnormii
+ [3]; /*!< The diagonal data points [i][i] of the normalized L matrix */
+ SCHAR Lnormii_sf[3];
+ FIXP_CHB Bmul0
+ [4]; /*!< To normalize L*x=b, Bmul0 is what we need to multiply b with. */
+ SCHAR Bmul0_sf[4];
+ FIXP_CHB LnormInv1d[6]; /*!< Normalized inverted L matrix (L') */
+ SCHAR LnormInv1d_sf[6];
+ FIXP_CHB
+ Bmul1[4]; /*!< To normalize L'*x=b, Bmul1 is what we need to multiply b
+ with. */
+ SCHAR Bmul1_sf[4];
+} backsubst_data;
+
+/* for each element n do, f(n) = trunc(log2(n))+1 */
+const UCHAR getLog2[32] = {0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
+ 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5};
+
+/** \def BSD_IDX_OFFSET
+ *
+ * bsd[] begins at index 0 with data for numBands=5. The correct bsd[] is
+ * indexed like bsd[numBands-BSD_IDX_OFFSET].
+ */
+#define BSD_IDX_OFFSET 5
+
+#define N_NUMBANDS \
+ MAXLOWBANDS - BSD_IDX_OFFSET + \
+ 1 /*!< Number of backsubst_data elements in bsd */
+
+const backsubst_data bsd[N_NUMBANDS] = {
+ {
+ /* numBands=5 */
+ {CHC(0x66c85a52), CHC(0x4278e587), CHC(0x697dcaff)},
+ {-1, 0, 0},
+ {CHC(0x66a61789), CHC(0x5253b8e3), CHC(0x5addad81)},
+ {3, 4, 1},
+ {CHC(0x7525ee90), CHC(0x6e2a1210), CHC(0x6523bb40), CHC(0x59822ead)},
+ {-6, -4, -2, 0},
+ {CHC(0x609e4cad), CHC(0x59c7e312), CHC(0x681eecac), CHC(0x440ea893),
+ CHC(0x4a214bb3), CHC(0x53c345a1)},
+ {1, 0, -1, -1, -3, -5},
+ {CHC(0x7525ee90), CHC(0x58587936), CHC(0x410d0b38), CHC(0x7f1519d6)},
+ {-6, -1, 2, 0},
+ },
+ {
+ /* numBands=6 */
+ {CHC(0x68943285), CHC(0x4841d2c3), CHC(0x6a6214c7)},
+ {-1, 0, 0},
+ {CHC(0x63c5923e), CHC(0x4e906e18), CHC(0x6285af8a)},
+ {3, 4, 1},
+ {CHC(0x7263940b), CHC(0x424a69a5), CHC(0x4ae8383a), CHC(0x517b7730)},
+ {-7, -4, -2, 0},
+ {CHC(0x518aee5f), CHC(0x4823a096), CHC(0x43764a39), CHC(0x6e6faf23),
+ CHC(0x61bba44f), CHC(0x59d8b132)},
+ {1, 0, -1, -2, -4, -6},
+ {CHC(0x7263940b), CHC(0x6757bff2), CHC(0x5bf40fe0), CHC(0x7d6f4292)},
+ {-7, -2, 1, 0},
+ },
+ {
+ /* numBands=7 */
+ {CHC(0x699b4c3c), CHC(0x4b8b702f), CHC(0x6ae51a4f)},
+ {-1, 0, 0},
+ {CHC(0x623a7f49), CHC(0x4ccc91fc), CHC(0x68f048dd)},
+ {3, 4, 1},
+ {CHC(0x7e6ebe18), CHC(0x5701daf2), CHC(0x74a8198b), CHC(0x4b399aa1)},
+ {-8, -5, -3, 0},
+ {CHC(0x464a64a6), CHC(0x78e42633), CHC(0x5ee174ba), CHC(0x5d0008c8),
+ CHC(0x455cff0f), CHC(0x6b9100e7)},
+ {1, -1, -2, -2, -4, -7},
+ {CHC(0x7e6ebe18), CHC(0x42c52efe), CHC(0x45fe401f), CHC(0x7b5808ef)},
+ {-8, -2, 1, 0},
+ },
+ {
+ /* numBands=8 */
+ {CHC(0x6a3fd9b4), CHC(0x4d99823f), CHC(0x6b372a94)},
+ {-1, 0, 0},
+ {CHC(0x614c6ef7), CHC(0x4bd06699), CHC(0x6e59cfca)},
+ {3, 4, 1},
+ {CHC(0x4c389cc5), CHC(0x79686681), CHC(0x5e2544c2), CHC(0x46305b43)},
+ {-8, -6, -3, 0},
+ {CHC(0x7b4ca7c6), CHC(0x68270ac5), CHC(0x467c644c), CHC(0x505c1b0f),
+ CHC(0x67a14778), CHC(0x45801767)},
+ {0, -1, -2, -2, -5, -7},
+ {CHC(0x4c389cc5), CHC(0x5c499ceb), CHC(0x6f863c9f), CHC(0x79059bfc)},
+ {-8, -3, 0, 0},
+ },
+ {
+ /* numBands=9 */
+ {CHC(0x6aad9988), CHC(0x4ef8ac18), CHC(0x6b6df116)},
+ {-1, 0, 0},
+ {CHC(0x60b159b0), CHC(0x4b33f772), CHC(0x72f5573d)},
+ {3, 4, 1},
+ {CHC(0x6206cb18), CHC(0x58a7d8dc), CHC(0x4e0b2d0b), CHC(0x4207ad84)},
+ {-9, -6, -3, 0},
+ {CHC(0x6dadadae), CHC(0x5b8b2cfc), CHC(0x6cf61db2), CHC(0x46c3c90b),
+ CHC(0x506314ea), CHC(0x5f034acd)},
+ {0, -1, -3, -2, -5, -8},
+ {CHC(0x6206cb18), CHC(0x42f8b8de), CHC(0x5bb4776f), CHC(0x769acc79)},
+ {-9, -3, 0, 0},
+ },
+ {
+ /* numBands=10 */
+ {CHC(0x6afa7252), CHC(0x4feed3ed), CHC(0x6b94504d)},
+ {-1, 0, 0},
+ {CHC(0x60467899), CHC(0x4acbafba), CHC(0x76eb327f)},
+ {3, 4, 1},
+ {CHC(0x42415b15), CHC(0x431080da), CHC(0x420f1c32), CHC(0x7d0c1aeb)},
+ {-9, -6, -3, -1},
+ {CHC(0x62b2c7a4), CHC(0x51b040a6), CHC(0x56caddb4), CHC(0x7e74a2c8),
+ CHC(0x4030adf5), CHC(0x43d1dc4f)},
+ {0, -1, -3, -3, -5, -8},
+ {CHC(0x42415b15), CHC(0x64e299b3), CHC(0x4d33b5e8), CHC(0x742cee5f)},
+ {-9, -4, 0, 0},
+ },
+ {
+ /* numBands=11 */
+ {CHC(0x6b3258bb), CHC(0x50a21233), CHC(0x6bb03c19)},
+ {-1, 0, 0},
+ {CHC(0x5ff997c6), CHC(0x4a82706e), CHC(0x7a5aae36)},
+ {3, 4, 1},
+ {CHC(0x5d2fb4fb), CHC(0x685bddd8), CHC(0x71b5e983), CHC(0x7708c90b)},
+ {-10, -7, -4, -1},
+ {CHC(0x59aceea2), CHC(0x49c428a0), CHC(0x46ca5527), CHC(0x724be884),
+ CHC(0x68e586da), CHC(0x643485b6)},
+ {0, -1, -3, -3, -6, -9},
+ {CHC(0x5d2fb4fb), CHC(0x4e3fad1a), CHC(0x42310ba2), CHC(0x71c8b3ce)},
+ {-10, -4, 0, 0},
+ },
+ {
+ /* numBands=12 */
+ {CHC(0x6b5c4726), CHC(0x5128a4a8), CHC(0x6bc52ee1)},
+ {-1, 0, 0},
+ {CHC(0x5fc06618), CHC(0x4a4ce559), CHC(0x7d5c16e9)},
+ {3, 4, 1},
+ {CHC(0x43af8342), CHC(0x531533d3), CHC(0x633660a6), CHC(0x71ce6052)},
+ {-10, -7, -4, -1},
+ {CHC(0x522373d7), CHC(0x434150cb), CHC(0x75b58afc), CHC(0x68474f2d),
+ CHC(0x575348a5), CHC(0x4c20973f)},
+ {0, -1, -4, -3, -6, -9},
+ {CHC(0x43af8342), CHC(0x7c4d3d11), CHC(0x732e13db), CHC(0x6f756ac4)},
+ {-10, -5, -1, 0},
+ },
+ {
+ /* numBands=13 */
+ {CHC(0x6b7c8953), CHC(0x51903fcd), CHC(0x6bd54d2e)},
+ {-1, 0, 0},
+ {CHC(0x5f94abf0), CHC(0x4a2480fa), CHC(0x40013553)},
+ {3, 4, 2},
+ {CHC(0x6501236e), CHC(0x436b9c4e), CHC(0x578d7881), CHC(0x6d34f92e)},
+ {-11, -7, -4, -1},
+ {CHC(0x4bc0e2b2), CHC(0x7b9d12ac), CHC(0x636c1c1b), CHC(0x5fe15c2b),
+ CHC(0x49d54879), CHC(0x7662cfa5)},
+ {0, -2, -4, -3, -6, -10},
+ {CHC(0x6501236e), CHC(0x64b059fe), CHC(0x656d8359), CHC(0x6d370900)},
+ {-11, -5, -1, 0},
+ },
+ {
+ /* numBands=14 */
+ {CHC(0x6b95e276), CHC(0x51e1b637), CHC(0x6be1f7ed)},
+ {-1, 0, 0},
+ {CHC(0x5f727a1c), CHC(0x4a053e9c), CHC(0x412e528c)},
+ {3, 4, 2},
+ {CHC(0x4d178bd4), CHC(0x6f33b4e8), CHC(0x4e028f7f), CHC(0x691ee104)},
+ {-11, -8, -4, -1},
+ {CHC(0x46473d3f), CHC(0x725bd0a6), CHC(0x55199885), CHC(0x58bcc56b),
+ CHC(0x7e7e6288), CHC(0x5ddef6eb)},
+ {0, -2, -4, -3, -7, -10},
+ {CHC(0x4d178bd4), CHC(0x52ebd467), CHC(0x5a395a6e), CHC(0x6b0f724f)},
+ {-11, -5, -1, 0},
+ },
+ {
+ /* numBands=15 */
+ {CHC(0x6baa2a22), CHC(0x5222eb91), CHC(0x6bec1a86)},
+ {-1, 0, 0},
+ {CHC(0x5f57393b), CHC(0x49ec8934), CHC(0x423b5b58)},
+ {3, 4, 2},
+ {CHC(0x77fd2486), CHC(0x5cfbdf2c), CHC(0x46153bd1), CHC(0x65757ed9)},
+ {-12, -8, -4, -1},
+ {CHC(0x41888ee6), CHC(0x6a661db3), CHC(0x49abc8c8), CHC(0x52965848),
+ CHC(0x6d9301b7), CHC(0x4bb04721)},
+ {0, -2, -4, -3, -7, -10},
+ {CHC(0x77fd2486), CHC(0x45424c68), CHC(0x50f33cc6), CHC(0x68ff43f0)},
+ {-12, -5, -1, 0},
+ },
+ {
+ /* numBands=16 */
+ {CHC(0x6bbaa499), CHC(0x5257ed94), CHC(0x6bf456e4)},
+ {-1, 0, 0},
+ {CHC(0x5f412594), CHC(0x49d8a766), CHC(0x432d1dbd)},
+ {3, 4, 2},
+ {CHC(0x5ef5cfde), CHC(0x4eafcd2d), CHC(0x7ed36893), CHC(0x62274b45)},
+ {-12, -8, -5, -1},
+ {CHC(0x7ac438f5), CHC(0x637aab21), CHC(0x4067617a), CHC(0x4d3c6ec7),
+ CHC(0x5fd6e0dd), CHC(0x7bd5f024)},
+ {-1, -2, -4, -3, -7, -11},
+ {CHC(0x5ef5cfde), CHC(0x751d0d4f), CHC(0x492b3c41), CHC(0x67065409)},
+ {-12, -6, -1, 0},
+ },
+ {
+ /* numBands=17 */
+ {CHC(0x6bc836c9), CHC(0x5283997e), CHC(0x6bfb1f5e)},
+ {-1, 0, 0},
+ {CHC(0x5f2f02b6), CHC(0x49c868e9), CHC(0x44078151)},
+ {3, 4, 2},
+ {CHC(0x4c43b65a), CHC(0x4349dcf6), CHC(0x73799e2d), CHC(0x5f267274)},
+ {-12, -8, -5, -1},
+ {CHC(0x73726394), CHC(0x5d68511a), CHC(0x7191bbcc), CHC(0x48898c70),
+ CHC(0x548956e1), CHC(0x66981ce8)},
+ {-1, -2, -5, -3, -7, -11},
+ {CHC(0x4c43b65a), CHC(0x64131116), CHC(0x429028e2), CHC(0x65240211)},
+ {-12, -6, -1, 0},
+ },
+ {
+ /* numBands=18 */
+ {CHC(0x6bd3860d), CHC(0x52a80156), CHC(0x6c00c68d)},
+ {-1, 0, 0},
+ {CHC(0x5f1fed86), CHC(0x49baf636), CHC(0x44cdb9dc)},
+ {3, 4, 2},
+ {CHC(0x7c189389), CHC(0x742666d8), CHC(0x69b8c776), CHC(0x5c67e27d)},
+ {-13, -9, -5, -1},
+ {CHC(0x6cf1ea76), CHC(0x58095703), CHC(0x64e351a9), CHC(0x4460da90),
+ CHC(0x4b1f8083), CHC(0x55f2d3e1)},
+ {-1, -2, -5, -3, -7, -11},
+ {CHC(0x7c189389), CHC(0x5651792a), CHC(0x79cb9b3d), CHC(0x635769c0)},
+ {-13, -6, -2, 0},
+ },
+ {
+ /* numBands=19 */
+ {CHC(0x6bdd0c40), CHC(0x52c6abf6), CHC(0x6c058950)},
+ {-1, 0, 0},
+ {CHC(0x5f133f88), CHC(0x49afb305), CHC(0x45826d73)},
+ {3, 4, 2},
+ {CHC(0x6621a164), CHC(0x6512528e), CHC(0x61449fc8), CHC(0x59e2a0c0)},
+ {-13, -9, -5, -1},
+ {CHC(0x6721cadb), CHC(0x53404cd4), CHC(0x5a389e91), CHC(0x40abcbd2),
+ CHC(0x43332f01), CHC(0x48b82e46)},
+ {-1, -2, -5, -3, -7, -11},
+ {CHC(0x6621a164), CHC(0x4b12cc28), CHC(0x6ffd4df8), CHC(0x619f835e)},
+ {-13, -6, -2, 0},
+ },
+ {
+ /* numBands=20 */
+ {CHC(0x6be524c5), CHC(0x52e0beb3), CHC(0x6c099552)},
+ {-1, 0, 0},
+ {CHC(0x5f087c68), CHC(0x49a62bb5), CHC(0x4627d175)},
+ {3, 4, 2},
+ {CHC(0x54ec6afe), CHC(0x58991a42), CHC(0x59e23e8c), CHC(0x578f4ef4)},
+ {-13, -9, -5, -1},
+ {CHC(0x61e78f6f), CHC(0x4ef5e1e9), CHC(0x5129c3b8), CHC(0x7ab0f7b2),
+ CHC(0x78efb076), CHC(0x7c2567ea)},
+ {-1, -2, -5, -4, -8, -12},
+ {CHC(0x54ec6afe), CHC(0x41c7812c), CHC(0x676f6f8d), CHC(0x5ffb383f)},
+ {-13, -6, -2, 0},
+ },
+ {
+ /* numBands=21 */
+ {CHC(0x6bec1542), CHC(0x52f71929), CHC(0x6c0d0d5e)},
+ {-1, 0, 0},
+ {CHC(0x5eff45c5), CHC(0x499e092d), CHC(0x46bfc0c9)},
+ {3, 4, 2},
+ {CHC(0x47457a78), CHC(0x4e2d99b3), CHC(0x53637ea5), CHC(0x5567d0e9)},
+ {-13, -9, -5, -1},
+ {CHC(0x5d2dc61b), CHC(0x4b1760c8), CHC(0x4967cf39), CHC(0x74b113d8),
+ CHC(0x6d6676b6), CHC(0x6ad114e9)},
+ {-1, -2, -5, -4, -8, -12},
+ {CHC(0x47457a78), CHC(0x740accaa), CHC(0x5feb6609), CHC(0x5e696f95)},
+ {-13, -7, -2, 0},
+ },
+ {
+ /* numBands=22 */
+ {CHC(0x6bf21387), CHC(0x530a683c), CHC(0x6c100c59)},
+ {-1, 0, 0},
+ {CHC(0x5ef752ea), CHC(0x499708c6), CHC(0x474bcd1b)},
+ {3, 4, 2},
+ {CHC(0x78a21ab7), CHC(0x45658aec), CHC(0x4da3c4fe), CHC(0x5367094b)},
+ {-14, -9, -5, -1},
+ {CHC(0x58e2df6a), CHC(0x4795990e), CHC(0x42b5e0f7), CHC(0x6f408c64),
+ CHC(0x6370bebf), CHC(0x5c91ca85)},
+ {-1, -2, -5, -4, -8, -12},
+ {CHC(0x78a21ab7), CHC(0x66f951d6), CHC(0x594605bb), CHC(0x5ce91657)},
+ {-14, -7, -2, 0},
+ },
+ {
+ /* numBands=23 */
+ {CHC(0x6bf749b2), CHC(0x531b3348), CHC(0x6c12a750)},
+ {-1, 0, 0},
+ {CHC(0x5ef06b17), CHC(0x4990f6c9), CHC(0x47cd4c5b)},
+ {3, 4, 2},
+ {CHC(0x66dede36), CHC(0x7bdf90a9), CHC(0x4885b2b9), CHC(0x5188a6b7)},
+ {-14, -10, -5, -1},
+ {CHC(0x54f85812), CHC(0x446414ae), CHC(0x79c8d519), CHC(0x6a4c2f31),
+ CHC(0x5ac8325f), CHC(0x50bf9200)},
+ {-1, -2, -6, -4, -8, -12},
+ {CHC(0x66dede36), CHC(0x5be0d90e), CHC(0x535cc453), CHC(0x5b7923f0)},
+ {-14, -7, -2, 0},
+ },
+ {
+ /* numBands=24 */
+ {CHC(0x6bfbd91d), CHC(0x5329e580), CHC(0x6c14eeed)},
+ {-1, 0, 0},
+ {CHC(0x5eea6179), CHC(0x498baa90), CHC(0x4845635d)},
+ {3, 4, 2},
+ {CHC(0x58559b7e), CHC(0x6f1b231f), CHC(0x43f1789b), CHC(0x4fc8fcb8)},
+ {-14, -10, -5, -1},
+ {CHC(0x51621775), CHC(0x417881a3), CHC(0x6f9ba9b6), CHC(0x65c412b2),
+ CHC(0x53352c61), CHC(0x46db9caf)},
+ {-1, -2, -6, -4, -8, -12},
+ {CHC(0x58559b7e), CHC(0x52636003), CHC(0x4e13b316), CHC(0x5a189cdf)},
+ {-14, -7, -2, 0},
+ },
+ {
+ /* numBands=25 */
+ {CHC(0x6bffdc73), CHC(0x5336d4af), CHC(0x6c16f084)},
+ {-1, 0, 0},
+ {CHC(0x5ee51249), CHC(0x498703cc), CHC(0x48b50e4f)},
+ {3, 4, 2},
+ {CHC(0x4c5616cf), CHC(0x641b9fad), CHC(0x7fa735e0), CHC(0x4e24e57a)},
+ {-14, -10, -6, -1},
+ {CHC(0x4e15f47a), CHC(0x7d9481d6), CHC(0x66a82f8a), CHC(0x619ae971),
+ CHC(0x4c8b2f5f), CHC(0x7d09ec11)},
+ {-1, -3, -6, -4, -8, -13},
+ {CHC(0x4c5616cf), CHC(0x4a3770fb), CHC(0x495402de), CHC(0x58c693fa)},
+ {-14, -7, -2, 0},
+ },
+ {
+ /* numBands=26 */
+ {CHC(0x6c036943), CHC(0x53424625), CHC(0x6c18b6dc)},
+ {-1, 0, 0},
+ {CHC(0x5ee060aa), CHC(0x4982e88a), CHC(0x491d277f)},
+ {3, 4, 2},
+ {CHC(0x425ada5b), CHC(0x5a9368ac), CHC(0x78380a42), CHC(0x4c99aa05)},
+ {-14, -10, -6, -1},
+ {CHC(0x4b0b569c), CHC(0x78a420da), CHC(0x5ebdf203), CHC(0x5dc57e63),
+ CHC(0x46a650ff), CHC(0x6ee13fb8)},
+ {-1, -3, -6, -4, -8, -13},
+ {CHC(0x425ada5b), CHC(0x4323073c), CHC(0x450ae92b), CHC(0x57822ad5)},
+ {-14, -7, -2, 0},
+ },
+ {
+ /* numBands=27 */
+ {CHC(0x6c06911a), CHC(0x534c7261), CHC(0x6c1a4aba)},
+ {-1, 0, 0},
+ {CHC(0x5edc3524), CHC(0x497f43c0), CHC(0x497e6cd8)},
+ {3, 4, 2},
+ {CHC(0x73fb550e), CHC(0x5244894f), CHC(0x717aad78), CHC(0x4b24ef6c)},
+ {-15, -10, -6, -1},
+ {CHC(0x483aebe4), CHC(0x74139116), CHC(0x57b58037), CHC(0x5a3a4f3c),
+ CHC(0x416950fe), CHC(0x62c7f4f2)},
+ {-1, -3, -6, -4, -8, -13},
+ {CHC(0x73fb550e), CHC(0x79efb994), CHC(0x4128cab7), CHC(0x564a919a)},
+ {-15, -8, -2, 0},
+ },
+ {
+ /* numBands=28 */
+ {CHC(0x6c096264), CHC(0x535587cd), CHC(0x6c1bb355)},
+ {-1, 0, 0},
+ {CHC(0x5ed87c76), CHC(0x497c0439), CHC(0x49d98452)},
+ {3, 4, 2},
+ {CHC(0x65dec5bf), CHC(0x4afd1ba3), CHC(0x6b58b4b3), CHC(0x49c4a7b0)},
+ {-15, -10, -6, -1},
+ {CHC(0x459e6eb1), CHC(0x6fd850b7), CHC(0x516e7be9), CHC(0x56f13d05),
+ CHC(0x79785594), CHC(0x58617de7)},
+ {-1, -3, -6, -4, -9, -13},
+ {CHC(0x65dec5bf), CHC(0x6f2168aa), CHC(0x7b41310f), CHC(0x551f0692)},
+ {-15, -8, -3, 0},
+ },
+ {
+ /* numBands=29 */
+ {CHC(0x6c0be913), CHC(0x535dacd5), CHC(0x6c1cf6a3)},
+ {-1, 0, 0},
+ {CHC(0x5ed526b4), CHC(0x49791bc5), CHC(0x4a2eff99)},
+ {3, 4, 2},
+ {CHC(0x59e44afe), CHC(0x44949ada), CHC(0x65bf36f5), CHC(0x487705a0)},
+ {-15, -10, -6, -1},
+ {CHC(0x43307779), CHC(0x6be959c4), CHC(0x4bce2122), CHC(0x53e34d89),
+ CHC(0x7115ff82), CHC(0x4f6421a1)},
+ {-1, -3, -6, -4, -9, -13},
+ {CHC(0x59e44afe), CHC(0x659eab7d), CHC(0x74cea459), CHC(0x53fed574)},
+ {-15, -8, -3, 0},
+ },
+ {
+ /* numBands=30 */
+ {CHC(0x6c0e2f17), CHC(0x53650181), CHC(0x6c1e199d)},
+ {-1, 0, 0},
+ {CHC(0x5ed2269f), CHC(0x49767e9e), CHC(0x4a7f5f0b)},
+ {3, 4, 2},
+ {CHC(0x4faa4ae6), CHC(0x7dd3bf11), CHC(0x609e2732), CHC(0x473a72e9)},
+ {-15, -11, -6, -1},
+ {CHC(0x40ec57c6), CHC(0x683ee147), CHC(0x46be261d), CHC(0x510a7983),
+ CHC(0x698a84cb), CHC(0x4794a927)},
+ {-1, -3, -6, -4, -9, -13},
+ {CHC(0x4faa4ae6), CHC(0x5d3615ad), CHC(0x6ee74773), CHC(0x52e956a1)},
+ {-15, -8, -3, 0},
+ },
+ {
+ /* numBands=31 */
+ {CHC(0x6c103cc9), CHC(0x536ba0ac), CHC(0x6c1f2070)},
+ {-1, 0, 0},
+ {CHC(0x5ecf711e), CHC(0x497422ea), CHC(0x4acb1438)},
+ {3, 4, 2},
+ {CHC(0x46e322ad), CHC(0x73c32f3c), CHC(0x5be7d172), CHC(0x460d8800)},
+ {-15, -11, -6, -1},
+ {CHC(0x7d9bf8ad), CHC(0x64d22351), CHC(0x422bdc81), CHC(0x4e6184aa),
+ CHC(0x62ba2375), CHC(0x40c325de)},
+ {-2, -3, -6, -4, -9, -13},
+ {CHC(0x46e322ad), CHC(0x55bef2a3), CHC(0x697b3135), CHC(0x51ddee4d)},
+ {-15, -8, -3, 0},
+ },
+ {
+ // numBands=32
+ {CHC(0x6c121933), CHC(0x5371a104), CHC(0x6c200ea0)},
+ {-1, 0, 0},
+ {CHC(0x5eccfcd3), CHC(0x49720060), CHC(0x4b1283f0)},
+ {3, 4, 2},
+ {CHC(0x7ea12a52), CHC(0x6aca3303), CHC(0x579072bf), CHC(0x44ef056e)},
+ {-16, -11, -6, -1},
+ {CHC(0x79a3a9ab), CHC(0x619d38fc), CHC(0x7c0f0734), CHC(0x4be3dd5d),
+ CHC(0x5c8d7163), CHC(0x7591065f)},
+ {-2, -3, -7, -4, -9, -14},
+ {CHC(0x7ea12a52), CHC(0x4f1782a6), CHC(0x647cbcb2), CHC(0x50dc0bb1)},
+ {-16, -8, -3, 0},
+ },
+};
+
+/** \def SUM_SAFETY
+ *
+ * SUM_SAFTEY defines the bits needed to right-shift every summand in
+ * order to be overflow-safe. In the two backsubst functions we sum up 4
+ * values. Since one of which is definitely not MAXVAL_DBL (the L[x][y]),
+ * we spare just 2 safety bits instead of 3.
+ */
+#define SUM_SAFETY 2
+
+/**
+ * \brief Solves L*x=b via backsubstitution according to the following
+ * structure:
+ *
+ * x[0] = b[0];
+ * x[1] = (b[1] - x[0]) / L[1][1];
+ * x[2] = (b[2] - x[1]*L[2][1] - x[0]) / L[2][2];
+ * x[3] = (b[3] - x[2]*L[3][2] - x[1]*L[3][1] - x[0]) / L[3][3];
+ *
+ * \param[in] numBands SBR crossover band index
+ * \param[in] b the b in L*x=b (one-dimensional)
+ * \param[out] x output polynomial coefficients (mantissa)
+ * \param[out] x_sf exponents of x[]
+ */
+static void backsubst_fw(const int numBands, const FIXP_DBL *const b,
+ FIXP_DBL *RESTRICT x, int *RESTRICT x_sf) {
+ int i, k;
+ int m; /* the trip counter that indexes incrementally through Lnorm1d[] */
+
+ const FIXP_CHB *RESTRICT pLnorm1d = bsd[numBands - BSD_IDX_OFFSET].Lnorm1d;
+ const SCHAR *RESTRICT pLnorm1d_sf = bsd[numBands - BSD_IDX_OFFSET].Lnorm1d_sf;
+ const FIXP_CHB *RESTRICT pLnormii = bsd[numBands - BSD_IDX_OFFSET].Lnormii;
+ const SCHAR *RESTRICT pLnormii_sf = bsd[numBands - BSD_IDX_OFFSET].Lnormii_sf;
+
+ x[0] = b[0];
+
+ for (i = 1, m = 0; i <= POLY_ORDER; ++i) {
+ FIXP_DBL sum = b[i] >> SUM_SAFETY;
+ int sum_sf = x_sf[i];
+ for (k = i - 1; k > 0; --k, ++m) {
+ int e;
+ FIXP_DBL mult = fMultNorm(FX_CHB2FX_DBL(pLnorm1d[m]), x[k], &e);
+ int mult_sf = pLnorm1d_sf[m] + x_sf[k] + e;
+
+ /* check if the new summand mult has a different sf than the sum currently
+ * has */
+ int diff = mult_sf - sum_sf;
+
+ if (diff > 0) {
+ /* yes, and it requires the sum to be adjusted (scaled down) */
+ sum >>= diff;
+ sum_sf = mult_sf;
+ } else if (diff < 0) {
+ /* yes, but here mult needs to be scaled down */
+ mult >>= -diff;
+ }
+ sum -= (mult >> SUM_SAFETY);
+ }
+
+ /* - x[0] */
+ if (x_sf[0] > sum_sf) {
+ sum >>= (x_sf[0] - sum_sf);
+ sum_sf = x_sf[0];
+ }
+ sum -= (x[0] >> (sum_sf - x_sf[0] + SUM_SAFETY));
+
+ /* instead of the division /L[i][i], we multiply by the inverse */
+ int e;
+ x[i] = fMultNorm(sum, FX_CHB2FX_DBL(pLnormii[i - 1]), &e);
+ x_sf[i] = sum_sf + pLnormii_sf[i - 1] + e + SUM_SAFETY;
+ }
+}
+
+/**
+ * \brief Solves L*x=b via backsubstitution according to the following
+ * structure:
+ *
+ * x[3] = b[3];
+ * x[2] = b[2] - L[2][3]*x[3];
+ * x[1] = b[1] - L[1][2]*x[2] - L[1][3]*x[3];
+ * x[0] = b[0] - L[0][1]*x[1] - L[0][2]*x[2] - L[0][3]*x[3];
+ *
+ * \param[in] numBands SBR crossover band index
+ * \param[in] b the b in L*x=b (one-dimensional)
+ * \param[out] x solution vector
+ * \param[out] x_sf exponents of x[]
+ */
+static void backsubst_bw(const int numBands, const FIXP_DBL *const b,
+ FIXP_DBL *RESTRICT x, int *RESTRICT x_sf) {
+ int i, k;
+ int m; /* the trip counter that indexes incrementally through LnormInv1d[] */
+
+ const FIXP_CHB *RESTRICT pLnormInv1d =
+ bsd[numBands - BSD_IDX_OFFSET].LnormInv1d;
+ const SCHAR *RESTRICT pLnormInv1d_sf =
+ bsd[numBands - BSD_IDX_OFFSET].LnormInv1d_sf;
+
+ x[POLY_ORDER] = b[POLY_ORDER];
+
+ for (i = POLY_ORDER - 1, m = 0; i >= 0; i--) {
+ FIXP_DBL sum = b[i] >> SUM_SAFETY;
+ int sum_sf = x_sf[i]; /* sum's sf but disregarding SUM_SAFETY (added at the
+ iteration's end) */
+
+ for (k = i + 1; k <= POLY_ORDER; ++k, ++m) {
+ int e;
+ FIXP_DBL mult = fMultNorm(FX_CHB2FX_DBL(pLnormInv1d[m]), x[k], &e);
+ int mult_sf = pLnormInv1d_sf[m] + x_sf[k] + e;
+
+ /* check if the new summand mult has a different sf than sum currently has
+ */
+ int diff = mult_sf - sum_sf;
+
+ if (diff > 0) {
+ /* yes, and it requires the sum v to be adjusted (scaled down) */
+ sum >>= diff;
+ sum_sf = mult_sf;
+ } else if (diff < 0) {
+ /* yes, but here mult needs to be scaled down */
+ mult >>= -diff;
+ }
+
+ /* mult has now the same sf than what it is about to be added to. */
+ /* scale mult down additionally so that building the sum is overflow-safe.
+ */
+ sum -= (mult >> SUM_SAFETY);
+ }
+
+ x_sf[i] = sum_sf + SUM_SAFETY;
+ x[i] = sum;
+ }
+}
+
+/**
+ * \brief Solves a system of linear equations (L*x=b) with the Cholesky
+ * algorithm.
+ *
+ * \param[in] numBands SBR crossover band index
+ * \param[in,out] b input: vector b, output: solution vector p.
+ * \param[in,out] b_sf input: exponent of b; output: exponent of solution
+ * p.
+ */
+static void choleskySolve(const int numBands, FIXP_DBL *RESTRICT b,
+ int *RESTRICT b_sf) {
+ int i, e;
+
+ const FIXP_CHB *RESTRICT pBmul0 = bsd[numBands - BSD_IDX_OFFSET].Bmul0;
+ const SCHAR *RESTRICT pBmul0_sf = bsd[numBands - BSD_IDX_OFFSET].Bmul0_sf;
+ const FIXP_CHB *RESTRICT pBmul1 = bsd[numBands - BSD_IDX_OFFSET].Bmul1;
+ const SCHAR *RESTRICT pBmul1_sf = bsd[numBands - BSD_IDX_OFFSET].Bmul1_sf;
+
+ /* normalize b */
+ FIXP_DBL bnormed[POLY_ORDER + 1];
+ for (i = 0; i <= POLY_ORDER; ++i) {
+ bnormed[i] = fMultNorm(b[i], FX_CHB2FX_DBL(pBmul0[i]), &e);
+ b_sf[i] += pBmul0_sf[i] + e;
+ }
+
+ backsubst_fw(numBands, bnormed, b, b_sf);
+
+ /* normalize b again */
+ for (i = 0; i <= POLY_ORDER; ++i) {
+ bnormed[i] = fMultNorm(b[i], FX_CHB2FX_DBL(pBmul1[i]), &e);
+ b_sf[i] += pBmul1_sf[i] + e;
+ }
+
+ backsubst_bw(numBands, bnormed, b, b_sf);
+}
+
+/**
+ * \brief Find polynomial approximation of vector y with implicit abscisas
+ * x=0,1,2,3..n-1
+ *
+ * The problem (V^T * V * p = V^T * y) is solved with Cholesky.
+ * V is the Vandermode Matrix constructed with x = 0...n-1;
+ * A = V^T * V; b = V^T * y;
+ *
+ * \param[in] numBands SBR crossover band index (BSD_IDX_OFFSET <= numBands <=
+ * MAXLOWBANDS)
+ * \param[in] y input vector (mantissa)
+ * \param[in] y_sf exponents of y[]
+ * \param[out] p output polynomial coefficients (mantissa)
+ * \param[out] p_sf exponents of p[]
+ */
+static void polyfit(const int numBands, const FIXP_DBL *const y, const int y_sf,
+ FIXP_DBL *RESTRICT p, int *RESTRICT p_sf) {
+ int i, k;
+ LONG v[POLY_ORDER + 1];
+ int sum_saftey = getLog2[numBands - 1];
+
+ FDK_ASSERT((numBands >= BSD_IDX_OFFSET) && (numBands <= MAXLOWBANDS));
+
+ /* construct vector b[] temporarily stored in array p[] */
+ FDKmemclear(p, (POLY_ORDER + 1) * sizeof(FIXP_DBL));
+
+ /* p[] are the sums over n values and each p[i] has its own sf */
+ for (i = 0; i <= POLY_ORDER; ++i) p_sf[i] = 1 - DFRACT_BITS;
+
+ for (k = 0; k < numBands; k++) {
+ v[0] = (LONG)1;
+ for (i = 1; i <= POLY_ORDER; i++) {
+ v[i] = k * v[i - 1];
+ }
+
+ for (i = 0; i <= POLY_ORDER; i++) {
+ if (v[POLY_ORDER - i] != 0 && y[k] != FIXP_DBL(0)) {
+ int e;
+ FIXP_DBL mult = fMultNorm((FIXP_DBL)v[POLY_ORDER - i], y[k], &e);
+ int sf = DFRACT_BITS - 1 + y_sf + e;
+
+ /* check if the new summand has a different sf than the sum p[i]
+ * currently has */
+ int diff = sf - p_sf[i];
+
+ if (diff > 0) {
+ /* yes, and it requires the sum p[i] to be adjusted (scaled down) */
+ p[i] >>= fMin(DFRACT_BITS - 1, diff);
+ p_sf[i] = sf;
+ } else if (diff < 0) {
+ /* yes, but here mult needs to be scaled down */
+ mult >>= -diff;
+ }
+
+ /* mult has now the same sf than what it is about to be added to.
+ scale mult down additionally so that building the sum is
+ overflow-safe. */
+ p[i] += mult >> sum_saftey;
+ }
+ }
+ }
+
+ p_sf[0] += sum_saftey;
+ p_sf[1] += sum_saftey;
+ p_sf[2] += sum_saftey;
+ p_sf[3] += sum_saftey;
+
+ choleskySolve(numBands, p, p_sf);
+}
+
+/**
+ * \brief Calculates the output of a POLY_ORDER-degree polynomial function
+ * with Horner scheme:
+ *
+ * y(x) = p3 + p2*x + p1*x^2 + p0*x^3
+ * = p3 + x*(p2 + x*(p1 + x*p0))
+ *
+ * The for loop iterates through the mult/add parts in y(x) as above,
+ * during which regular upscaling ensures a stable exponent of the
+ * result.
+ *
+ * \param[in] p coefficients as in y(x)
+ * \param[in] p_sf exponents of p[]
+ * \param[in] x_int non-fractional integer representation of x as in y(x)
+ * \param[out] out_sf exponent of return value
+ *
+ * \return result y(x)
+ */
+static FIXP_DBL polyval(const FIXP_DBL *const p, const int *const p_sf,
+ const int x_int, int *out_sf) {
+ FDK_ASSERT(x_int <= 31); /* otherwise getLog2[] needs more elements */
+
+ int k, x_sf;
+ int result_sf; /* working space to compute return value *out_sf */
+ FIXP_DBL x; /* fractional value of x_int */
+ FIXP_DBL result; /* return value */
+
+ /* if x == 0, then y(x) is just p3 */
+ if (x_int != 0) {
+ x_sf = getLog2[x_int];
+ x = (FIXP_DBL)x_int << (DFRACT_BITS - 1 - x_sf);
+ } else {
+ *out_sf = p_sf[3];
+ return p[3];
+ }
+
+ result = p[0];
+ result_sf = p_sf[0];
+
+ for (k = 1; k <= POLY_ORDER; ++k) {
+ FIXP_DBL mult = fMult(x, result);
+ int mult_sf = x_sf + result_sf;
+
+ int room = CountLeadingBits(mult);
+ mult <<= room;
+ mult_sf -= room;
+
+ FIXP_DBL pp = p[k];
+ int pp_sf = p_sf[k];
+
+ /* equalize the shift factors of pp and mult so that we can sum them up */
+ int diff = pp_sf - mult_sf;
+
+ if (diff > 0) {
+ diff = fMin(diff, DFRACT_BITS - 1);
+ mult >>= diff;
+ } else if (diff < 0) {
+ diff = fMax(diff, 1 - DFRACT_BITS);
+ pp >>= -diff;
+ }
+
+ /* downshift by 1 to ensure safe summation */
+ mult >>= 1;
+ mult_sf++;
+ pp >>= 1;
+ pp_sf++;
+
+ result_sf = fMax(pp_sf, mult_sf);
+
+ result = mult + pp;
+ /* rarely, mult and pp happen to be almost equal except their sign,
+ and then upon summation, result becomes so small, that it is within
+ the inaccuracy range of a few bits, and then the relative error
+ produced by this function may become HUGE */
+ }
+
+ *out_sf = result_sf;
+ return result;
+}
+
+void sbrDecoder_calculateGainVec(FIXP_DBL **sourceBufferReal,
+ FIXP_DBL **sourceBufferImag,
+ int sourceBuf_e_overlap,
+ int sourceBuf_e_current, int overlap,
+ FIXP_DBL *RESTRICT GainVec, int *GainVec_exp,
+ int numBands, const int startSample,
+ const int stopSample) {
+ FIXP_DBL p[POLY_ORDER + 1];
+ FIXP_DBL meanNrg;
+ FIXP_DBL LowEnv[MAXLOWBANDS];
+ FIXP_DBL invNumBands = GetInvInt(numBands);
+ FIXP_DBL invNumSlots = GetInvInt(stopSample - startSample);
+ int i, loBand, exp, scale_nrg, scale_nrg_ov;
+ int sum_scale = 5, sum_scale_ov = 3;
+
+ if (overlap > 8) {
+ FDK_ASSERT(overlap <= 16);
+ sum_scale_ov += 1;
+ sum_scale += 1;
+ }
+
+ /* exponents of energy values */
+ sourceBuf_e_overlap = sourceBuf_e_overlap * 2 + sum_scale_ov;
+ sourceBuf_e_current = sourceBuf_e_current * 2 + sum_scale;
+ exp = fMax(sourceBuf_e_overlap, sourceBuf_e_current);
+ scale_nrg = sourceBuf_e_current - exp;
+ scale_nrg_ov = sourceBuf_e_overlap - exp;
+
+ meanNrg = (FIXP_DBL)0;
+ /* Calculate the spectral envelope in dB over the current copy-up frame. */
+ for (loBand = 0; loBand < numBands; loBand++) {
+ FIXP_DBL nrg_ov, nrg;
+ INT reserve = 0, exp_new;
+ FIXP_DBL maxVal = FL2FX_DBL(0.0f);
+
+ for (i = startSample; i < stopSample; i++) {
+ maxVal |=
+ (FIXP_DBL)((LONG)(sourceBufferReal[i][loBand]) ^
+ ((LONG)sourceBufferReal[i][loBand] >> (SAMPLE_BITS - 1)));
+ maxVal |=
+ (FIXP_DBL)((LONG)(sourceBufferImag[i][loBand]) ^
+ ((LONG)sourceBufferImag[i][loBand] >> (SAMPLE_BITS - 1)));
+ }
+
+ if (maxVal != FL2FX_DBL(0.0f)) {
+ reserve = fixMax(0, CntLeadingZeros(maxVal) - 2);
+ }
+
+ nrg_ov = nrg = (FIXP_DBL)0;
+ if (scale_nrg_ov > -31) {
+ for (i = startSample; i < overlap; i++) {
+ nrg_ov += (fPow2Div2(sourceBufferReal[i][loBand] << reserve) +
+ fPow2Div2(sourceBufferImag[i][loBand] << reserve)) >>
+ sum_scale_ov;
+ }
+ } else {
+ scale_nrg_ov = 0;
+ }
+ if (scale_nrg > -31) {
+ for (i = overlap; i < stopSample; i++) {
+ nrg += (fPow2Div2(sourceBufferReal[i][loBand] << reserve) +
+ fPow2Div2(sourceBufferImag[i][loBand] << reserve)) >>
+ sum_scale;
+ }
+ } else {
+ scale_nrg = 0;
+ }
+
+ nrg = (scaleValue(nrg_ov, scale_nrg_ov) >> 1) +
+ (scaleValue(nrg, scale_nrg) >> 1);
+ nrg = fMult(nrg, invNumSlots);
+
+ exp_new =
+ exp - (2 * reserve) +
+ 2; /* +1 for addition directly above, +1 for fPow2Div2 in loops above */
+
+ /* LowEnv = 10*log10(nrg) = log2(nrg) * 10/log2(10) */
+ /* exponent of logarithmic energy is 8 */
+ if (nrg > (FIXP_DBL)0) {
+ int exp_log2;
+ nrg = CalcLog2(nrg, exp_new, &exp_log2);
+ nrg = scaleValue(nrg, exp_log2 - 6);
+ nrg = fMult(FL2FXCONST_SGL(LOG10FAC), nrg);
+ } else {
+ nrg = (FIXP_DBL)0;
+ }
+ LowEnv[loBand] = nrg;
+ meanNrg += fMult(nrg, invNumBands);
+ }
+ exp = 6 + 2; /* exponent of LowEnv: +2 is exponent of LOG10FAC */
+
+ /* subtract mean before polynomial approximation to reduce dynamic of p[] */
+ for (loBand = 0; loBand < numBands; loBand++) {
+ LowEnv[loBand] = meanNrg - LowEnv[loBand];
+ }
+
+ /* For numBands < BSD_IDX_OFFSET (== POLY_ORDER+2) we dont get an
+ overdetermined equation system. The calculated polynomial will exactly fit
+ the input data and evaluating the polynomial will lead to the same vector
+ than the original input vector: lowEnvSlope[] == lowEnv[]
+ */
+ if (numBands > POLY_ORDER + 1) {
+ /* Find polynomial approximation of LowEnv */
+ int p_sf[POLY_ORDER + 1];
+
+ polyfit(numBands, LowEnv, exp, p, p_sf);
+
+ for (i = 0; i < numBands; i++) {
+ int sf;
+
+ /* lowBandEnvSlope[i] = tmp; */
+ FIXP_DBL tmp = polyval(p, p_sf, i, &sf);
+
+ /* GainVec = 10^((mean(y)-y)/20) = 2^( (mean(y)-y) * log2(10)/20 ) */
+ tmp = fMult(tmp, FL2FXCONST_SGL(LOG10FAC_INV));
+ GainVec[i] = f2Pow(tmp, sf - 2,
+ &GainVec_exp[i]); /* -2 is exponent of LOG10FAC_INV */
+ }
+ } else { /* numBands <= POLY_ORDER+1 */
+ for (i = 0; i < numBands; i++) {
+ int sf = exp; /* exponent of LowEnv[] */
+
+ /* lowBandEnvSlope[i] = LowEnv[i]; */
+ FIXP_DBL tmp = LowEnv[i];
+
+ /* GainVec = 10^((mean(y)-y)/20) = 2^( (mean(y)-y) * log2(10)/20 ) */
+ tmp = fMult(tmp, FL2FXCONST_SGL(LOG10FAC_INV));
+ GainVec[i] = f2Pow(tmp, sf - 2,
+ &GainVec_exp[i]); /* -2 is exponent of LOG10FAC_INV */
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 17:20:24 +0000