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1 /* -----------------------------------------------------------------------------
2 Software License for The Fraunhofer FDK AAC Codec Library for Android
3 
4 © Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
5 Forschung e.V. All rights reserved.
6 
7  1.    INTRODUCTION
8 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
9 that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
10 scheme for digital audio. This FDK AAC Codec software is intended to be used on
11 a wide variety of Android devices.
12 
13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
14 general perceptual audio codecs. AAC-ELD is considered the best-performing
15 full-bandwidth communications codec by independent studies and is widely
16 deployed. AAC has been standardized by ISO and IEC as part of the MPEG
17 specifications.
18 
19 Patent licenses for necessary patent claims for the FDK AAC Codec (including
20 those of Fraunhofer) may be obtained through Via Licensing
21 (www.vialicensing.com) or through the respective patent owners individually for
22 the purpose of encoding or decoding bit streams in products that are compliant
23 with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
24 Android devices already license these patent claims through Via Licensing or
25 directly from the patent owners, and therefore FDK AAC Codec software may
26 already be covered under those patent licenses when it is used for those
27 licensed purposes only.
28 
29 Commercially-licensed AAC software libraries, including floating-point versions
30 with enhanced sound quality, are also available from Fraunhofer. Users are
31 encouraged to check the Fraunhofer website for additional applications
32 information and documentation.
33 
34 2.    COPYRIGHT LICENSE
35 
36 Redistribution and use in source and binary forms, with or without modification,
37 are permitted without payment of copyright license fees provided that you
38 satisfy the following conditions:
39 
40 You must retain the complete text of this software license in redistributions of
41 the FDK AAC Codec or your modifications thereto in source code form.
42 
43 You must retain the complete text of this software license in the documentation
44 and/or other materials provided with redistributions of the FDK AAC Codec or
45 your modifications thereto in binary form. You must make available free of
46 charge copies of the complete source code of the FDK AAC Codec and your
47 modifications thereto to recipients of copies in binary form.
48 
49 The name of Fraunhofer may not be used to endorse or promote products derived
50 from this library without prior written permission.
51 
52 You may not charge copyright license fees for anyone to use, copy or distribute
53 the FDK AAC Codec software or your modifications thereto.
54 
55 Your modified versions of the FDK AAC Codec must carry prominent notices stating
56 that you changed the software and the date of any change. For modified versions
57 of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
58 must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
59 AAC Codec Library for Android."
60 
61 3.    NO PATENT LICENSE
62 
63 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
64 limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
65 Fraunhofer provides no warranty of patent non-infringement with respect to this
66 software.
67 
68 You may use this FDK AAC Codec software or modifications thereto only for
69 purposes that are authorized by appropriate patent licenses.
70 
71 4.    DISCLAIMER
72 
73 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
74 holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
75 including but not limited to the implied warranties of merchantability and
76 fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
77 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
78 or consequential damages, including but not limited to procurement of substitute
79 goods or services; loss of use, data, or profits, or business interruption,
80 however caused and on any theory of liability, whether in contract, strict
81 liability, or tort (including negligence), arising in any way out of the use of
82 this software, even if advised of the possibility of such damage.
83 
84 5.    CONTACT INFORMATION
85 
86 Fraunhofer Institute for Integrated Circuits IIS
87 Attention: Audio and Multimedia Departments - FDK AAC LL
88 Am Wolfsmantel 33
89 91058 Erlangen, Germany
90 
91 www.iis.fraunhofer.de/amm
92 amm-info@iis.fraunhofer.de
93 ----------------------------------------------------------------------------- */
94 
95 /**************************** AAC decoder library ******************************
96 
97    Author(s):
98 
99    Description: low delay filterbank
100 
101 *******************************************************************************/
102 
103 #include "ldfiltbank.h"
104 
105 #include "aac_rom.h"
106 #include "dct.h"
107 #include "FDK_tools_rom.h"
108 #include "mdct.h"
109 
110 #define LDFB_HEADROOM 2
111 
112 #if defined(__arm__)
113 #endif
114 
multE2_DinvF_fdk(FIXP_PCM * output,FIXP_DBL * x,const FIXP_WTB * fb,FIXP_DBL * z,const int N)115 static void multE2_DinvF_fdk(FIXP_PCM *output, FIXP_DBL *x, const FIXP_WTB *fb,
116                              FIXP_DBL *z, const int N) {
117   int i;
118 
119   /*  scale for FIXP_DBL -> INT_PCM conversion. */
120   const int scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM;
121 #if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
122   FIXP_DBL rnd_val_wts0 = (FIXP_DBL)0;
123   FIXP_DBL rnd_val_wts1 = (FIXP_DBL)0;
124   if (-WTS0 - 1 + scale)
125     rnd_val_wts0 = (FIXP_DBL)(1 << (-WTS0 - 1 + scale - 1));
126   if (-WTS1 - 1 + scale)
127     rnd_val_wts1 = (FIXP_DBL)(1 << (-WTS1 - 1 + scale - 1));
128 #endif
129 
130   for (i = 0; i < N / 4; i++) {
131     FIXP_DBL z0, z2, tmp;
132 
133     z2 = x[N / 2 + i];
134     z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1));
135 
136     z[N / 2 + i] = x[N / 2 - 1 - i] +
137                    (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1));
138 
139     tmp = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
140            fMultDiv2(z[i], fb[N + N / 2 + i]));
141 
142 #if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
143     FDK_ASSERT((-WTS1 - 1 + scale) >= 0);
144     FDK_ASSERT(tmp <= ((FIXP_DBL)0x7FFFFFFF -
145                        rnd_val_wts1)); /* rounding must not cause overflow */
146     output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
147         tmp + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
148 #else
149     FDK_ASSERT((WTS1 + 1 - scale) >= 0);
150     output[(N * 3 / 4 - 1 - i)] =
151         (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1 + 1 - scale, PCM_OUT_BITS);
152 #endif
153 
154     z[i] = z0;
155     z[N + i] = z2;
156   }
157 
158   for (i = N / 4; i < N / 2; i++) {
159     FIXP_DBL z0, z2, tmp0, tmp1;
160 
161     z2 = x[N / 2 + i];
162     z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1));
163 
164     z[N / 2 + i] = x[N / 2 - 1 - i] +
165                    (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1));
166 
167     tmp0 = (fMultDiv2(z[N / 2 + i], fb[N / 2 - 1 - i]) +
168             fMultDiv2(z[i], fb[N / 2 + i]));
169     tmp1 = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
170             fMultDiv2(z[i], fb[N + N / 2 + i]));
171 
172 #if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
173     FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
174     FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
175                         rnd_val_wts0)); /* rounding must not cause overflow */
176     FDK_ASSERT(tmp1 <= ((FIXP_DBL)0x7FFFFFFF -
177                         rnd_val_wts1)); /* rounding must not cause overflow */
178     output[(i - N / 4)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
179         tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
180     output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
181         tmp1 + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
182 #else
183     FDK_ASSERT((WTS0 + 1 - scale) >= 0);
184     output[(i - N / 4)] =
185         (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
186     output[(N * 3 / 4 - 1 - i)] =
187         (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1 + 1 - scale, PCM_OUT_BITS);
188 #endif
189     z[i] = z0;
190     z[N + i] = z2;
191   }
192 
193   /* Exchange quarter parts of x to bring them in the "right" order */
194   for (i = 0; i < N / 4; i++) {
195     FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N / 2 + i]);
196 
197 #if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0)
198     FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
199     FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
200                         rnd_val_wts0)); /* rounding must not cause overflow */
201     output[(N * 3 / 4 + i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT(
202         tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
203 #else
204     FDK_ASSERT((WTS0 + 1 - scale) >= 0);
205     output[(N * 3 / 4 + i)] =
206         (FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
207 #endif
208   }
209 }
210 
InvMdctTransformLowDelay_fdk(FIXP_DBL * mdctData,const int mdctData_e,FIXP_PCM * output,FIXP_DBL * fs_buffer,const int N)211 int InvMdctTransformLowDelay_fdk(FIXP_DBL *mdctData, const int mdctData_e,
212                                  FIXP_PCM *output, FIXP_DBL *fs_buffer,
213                                  const int N) {
214   const FIXP_WTB *coef;
215   FIXP_DBL gain = (FIXP_DBL)0;
216   int scale = mdctData_e + MDCT_OUT_HEADROOM -
217               LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside
218                                 multE2_DinvF_fdk() below */
219   int i;
220 
221   /* Select LD window slope */
222   switch (N) {
223     case 256:
224       coef = LowDelaySynthesis256;
225       break;
226     case 240:
227       coef = LowDelaySynthesis240;
228       break;
229     case 160:
230       coef = LowDelaySynthesis160;
231       break;
232     case 128:
233       coef = LowDelaySynthesis128;
234       break;
235     case 120:
236       coef = LowDelaySynthesis120;
237       break;
238     case 512:
239       coef = LowDelaySynthesis512;
240       break;
241     case 480:
242     default:
243       coef = LowDelaySynthesis480;
244       break;
245   }
246 
247   /*
248      Apply exponent and 1/N factor.
249      Note: "scale" is off by one because for LD_MDCT the window length is twice
250      the window length of a regular MDCT. This is corrected inside
251      multE2_DinvF_fdk(). Refer to ISO/IEC 14496-3:2009 page 277,
252      chapter 4.6.20.2 "Low Delay Window".
253    */
254   imdct_gain(&gain, &scale, N);
255 
256   dct_IV(mdctData, N, &scale);
257 
258   if (N == 256 || N == 240 || N == 160) {
259     scale -= 1;
260   } else if (N == 128 || N == 120) {
261     scale -= 2;
262   }
263 
264   if (gain != (FIXP_DBL)0) {
265     for (i = 0; i < N; i++) {
266       mdctData[i] = fMult(mdctData[i], gain);
267     }
268   }
269   scaleValuesSaturate(mdctData, N, scale);
270 
271   /* Since all exponent and factors have been applied, current exponent is zero.
272    */
273   multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N);
274 
275   return (1);
276 }
277