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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
+----------------------------------------------------------------------------- */
+
+/**************************** AAC decoder library ******************************
+
+ Author(s):
+
+ Description: low delay filterbank
+
+*******************************************************************************/
+
+#include "ldfiltbank.h"
+
+#include "aac_rom.h"
+#include "dct.h"
+#include "FDK_tools_rom.h"
+#include "mdct.h"
+
+#define LDFB_HEADROOM 2
+
+#if defined(__arm__)
+#endif
+
+static void multE2_DinvF_fdk(FIXP_PCM *output, FIXP_DBL *x, const FIXP_WTB *fb,
+ FIXP_DBL *z, const int N) {
+ int i;
+
+ /* scale for FIXP_DBL -> INT_PCM conversion. */
+ const int scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM;
+#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
+ FIXP_DBL rnd_val_wts0 = (FIXP_DBL)0;
+ FIXP_DBL rnd_val_wts1 = (FIXP_DBL)0;
+ if (-WTS0 - 1 + scale)
+ rnd_val_wts0 = (FIXP_DBL)(1 << (-WTS0 - 1 + scale - 1));
+ if (-WTS1 - 1 + scale)
+ rnd_val_wts1 = (FIXP_DBL)(1 << (-WTS1 - 1 + scale - 1));
+#endif
+
+ for (i = 0; i < N / 4; i++) {
+ FIXP_DBL z0, z2, tmp;
+
+ z2 = x[N / 2 + i];
+ z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1));
+
+ z[N / 2 + i] = x[N / 2 - 1 - i] +
+ (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1));
+
+ tmp = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
+ fMultDiv2(z[i], fb[N + N / 2 + i]));
+
+#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
+ FDK_ASSERT((-WTS1 - 1 + scale) >= 0);
+ FDK_ASSERT(tmp <= ((FIXP_DBL)0x7FFFFFFF -
+ rnd_val_wts1)); /* rounding must not cause overflow */
+ output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
+ tmp + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
+#else
+ FDK_ASSERT((WTS1 + 1 - scale) >= 0);
+ output[(N * 3 / 4 - 1 - i)] =
+ (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1 + 1 - scale, PCM_OUT_BITS);
+#endif
+
+ z[i] = z0;
+ z[N + i] = z2;
+ }
+
+ for (i = N / 4; i < N / 2; i++) {
+ FIXP_DBL z0, z2, tmp0, tmp1;
+
+ z2 = x[N / 2 + i];
+ z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1));
+
+ z[N / 2 + i] = x[N / 2 - 1 - i] +
+ (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1));
+
+ tmp0 = (fMultDiv2(z[N / 2 + i], fb[N / 2 - 1 - i]) +
+ fMultDiv2(z[i], fb[N / 2 + i]));
+ tmp1 = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
+ fMultDiv2(z[i], fb[N + N / 2 + i]));
+
+#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
+ FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
+ FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
+ rnd_val_wts0)); /* rounding must not cause overflow */
+ FDK_ASSERT(tmp1 <= ((FIXP_DBL)0x7FFFFFFF -
+ rnd_val_wts1)); /* rounding must not cause overflow */
+ output[(i - N / 4)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
+ tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
+ output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
+ tmp1 + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
+#else
+ FDK_ASSERT((WTS0 + 1 - scale) >= 0);
+ output[(i - N / 4)] =
+ (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
+ output[(N * 3 / 4 - 1 - i)] =
+ (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1 + 1 - scale, PCM_OUT_BITS);
+#endif
+ z[i] = z0;
+ z[N + i] = z2;
+ }
+
+ /* Exchange quarter parts of x to bring them in the "right" order */
+ for (i = 0; i < N / 4; i++) {
+ FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N / 2 + i]);
+
+#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
+ FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
+ FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
+ rnd_val_wts0)); /* rounding must not cause overflow */
+ output[(N * 3 / 4 + i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
+ tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
+#else
+ FDK_ASSERT((WTS0 + 1 - scale) >= 0);
+ output[(N * 3 / 4 + i)] =
+ (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
+#endif
+ }
+}
+
+int InvMdctTransformLowDelay_fdk(FIXP_DBL *mdctData, const int mdctData_e,
+ FIXP_PCM *output, FIXP_DBL *fs_buffer,
+ const int N) {
+ const FIXP_WTB *coef;
+ FIXP_DBL gain = (FIXP_DBL)0;
+ int scale = mdctData_e + MDCT_OUT_HEADROOM -
+ LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside
+ multE2_DinvF_fdk() below */
+ int i;
+
+ /* Select LD window slope */
+ switch (N) {
+ case 256:
+ coef = LowDelaySynthesis256;
+ break;
+ case 240:
+ coef = LowDelaySynthesis240;
+ break;
+ case 160:
+ coef = LowDelaySynthesis160;
+ break;
+ case 128:
+ coef = LowDelaySynthesis128;
+ break;
+ case 120:
+ coef = LowDelaySynthesis120;
+ break;
+ case 512:
+ coef = LowDelaySynthesis512;
+ break;
+ case 480:
+ default:
+ coef = LowDelaySynthesis480;
+ break;
+ }
+
+ /*
+ Apply exponent and 1/N factor.
+ Note: "scale" is off by one because for LD_MDCT the window length is twice
+ the window length of a regular MDCT. This is corrected inside
+ multE2_DinvF_fdk(). Refer to ISO/IEC 14496-3:2009 page 277,
+ chapter 4.6.20.2 "Low Delay Window".
+ */
+ imdct_gain(&gain, &scale, N);
+
+ dct_IV(mdctData, N, &scale);
+
+ if (N == 256 || N == 240 || N == 160) {
+ scale -= 1;
+ } else if (N == 128 || N == 120) {
+ scale -= 2;
+ }
+
+ if (gain != (FIXP_DBL)0) {
+ for (i = 0; i < N; i++) {
+ mdctData[i] = fMult(mdctData[i], gain);
+ }
+ }
+ scaleValuesSaturate(mdctData, N, scale);
+
+ /* Since all exponent and factors have been applied, current exponent is zero.
+ */
+ multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N);
+
+ return (1);
+}
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