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