1 /* -----------------------------------------------------------------------------
2 Software License for The Fraunhofer FDK AAC Codec Library for Android
3
4 © Copyright 1995 - 2019 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 [email protected]
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(PCM_DEC * output,FIXP_DBL * x,const FIXP_WTB * fb,FIXP_DBL * z,const int N)115 static void multE2_DinvF_fdk(PCM_DEC *output, FIXP_DBL *x, const FIXP_WTB *fb,
116 FIXP_DBL *z, const int N) {
117 int i;
118
119 /* scale for FIXP_DBL -> PCM_DEC conversion: */
120 const int scale = (DFRACT_BITS - PCM_OUT_BITS) - LDFB_HEADROOM + (3);
121
122 #if ((DFRACT_BITS - PCM_OUT_BITS - LDFB_HEADROOM + (3) - 1) > 0)
123 FIXP_DBL rnd_val_wts0 = (FIXP_DBL)0;
124 FIXP_DBL rnd_val_wts1 = (FIXP_DBL)0;
125 #if ((DFRACT_BITS - PCM_OUT_BITS - LDFB_HEADROOM + (3) - WTS0 - 1) > 0)
126 if (-WTS0 - 1 + scale)
127 rnd_val_wts0 = (FIXP_DBL)(1 << (-WTS0 - 1 + scale - 1));
128 #endif
129 if (-WTS1 - 1 + scale)
130 rnd_val_wts1 = (FIXP_DBL)(1 << (-WTS1 - 1 + scale - 1));
131 #endif
132
133 for (i = 0; i < N / 4; i++) {
134 FIXP_DBL z0, z2, tmp;
135
136 z2 = x[N / 2 + i];
137 z0 = fAddSaturate(z2,
138 (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1)));
139
140 z[N / 2 + i] = fAddSaturate(
141 x[N / 2 - 1 - i],
142 (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1)));
143
144 tmp = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
145 fMultDiv2(z[i], fb[N + N / 2 + i]));
146
147 #if ((DFRACT_BITS - PCM_OUT_BITS - LDFB_HEADROOM + (3) - 1) > 0)
148 FDK_ASSERT((-WTS1 - 1 + scale) >= 0);
149 FDK_ASSERT(tmp <= ((FIXP_DBL)0x7FFFFFFF -
150 rnd_val_wts1)); /* rounding must not cause overflow */
151 output[(N * 3 / 4 - 1 - i)] = (PCM_DEC)SATURATE_RIGHT_SHIFT(
152 tmp + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
153 #else
154 FDK_ASSERT((WTS1 + 1 - scale) >= 0);
155 output[(N * 3 / 4 - 1 - i)] =
156 (PCM_DEC)SATURATE_LEFT_SHIFT(tmp, WTS1 + 1 - scale, PCM_OUT_BITS);
157 #endif
158
159 z[i] = z0;
160 z[N + i] = z2;
161 }
162
163 for (i = N / 4; i < N / 2; i++) {
164 FIXP_DBL z0, z2, tmp0, tmp1;
165
166 z2 = x[N / 2 + i];
167 z0 = fAddSaturate(z2,
168 (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1)));
169
170 z[N / 2 + i] = fAddSaturate(
171 x[N / 2 - 1 - i],
172 (fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1)));
173
174 tmp0 = (fMultDiv2(z[N / 2 + i], fb[N / 2 - 1 - i]) +
175 fMultDiv2(z[i], fb[N / 2 + i]));
176 tmp1 = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) +
177 fMultDiv2(z[i], fb[N + N / 2 + i]));
178
179 #if ((DFRACT_BITS - PCM_OUT_BITS - LDFB_HEADROOM + (3) - 1) > 0)
180 FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
181 FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
182 rnd_val_wts0)); /* rounding must not cause overflow */
183 FDK_ASSERT(tmp1 <= ((FIXP_DBL)0x7FFFFFFF -
184 rnd_val_wts1)); /* rounding must not cause overflow */
185 output[(i - N / 4)] = (PCM_DEC)SATURATE_RIGHT_SHIFT(
186 tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
187 output[(N * 3 / 4 - 1 - i)] = (PCM_DEC)SATURATE_RIGHT_SHIFT(
188 tmp1 + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS);
189 #else
190 FDK_ASSERT((WTS0 + 1 - scale) >= 0);
191 output[(i - N / 4)] =
192 (PCM_DEC)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
193 output[(N * 3 / 4 - 1 - i)] =
194 (PCM_DEC)SATURATE_LEFT_SHIFT(tmp1, WTS1 + 1 - scale, PCM_OUT_BITS);
195 #endif
196 z[i] = z0;
197 z[N + i] = z2;
198 }
199
200 /* Exchange quarter parts of x to bring them in the "right" order */
201 for (i = 0; i < N / 4; i++) {
202 FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N / 2 + i]);
203
204 #if ((DFRACT_BITS - PCM_OUT_BITS - LDFB_HEADROOM + (3) - 1) > 0)
205 FDK_ASSERT((-WTS0 - 1 + scale) >= 0);
206 FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF -
207 rnd_val_wts0)); /* rounding must not cause overflow */
208 output[(N * 3 / 4 + i)] = (PCM_DEC)SATURATE_RIGHT_SHIFT(
209 tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS);
210 #else
211 FDK_ASSERT((WTS0 + 1 - scale) >= 0);
212 output[(N * 3 / 4 + i)] =
213 (PCM_DEC)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS);
214 #endif
215 }
216 }
217
InvMdctTransformLowDelay_fdk(FIXP_DBL * mdctData,const int mdctData_e,PCM_DEC * output,FIXP_DBL * fs_buffer,const int N)218 int InvMdctTransformLowDelay_fdk(FIXP_DBL *mdctData, const int mdctData_e,
219 PCM_DEC *output, FIXP_DBL *fs_buffer,
220 const int N) {
221 const FIXP_WTB *coef;
222 FIXP_DBL gain = (FIXP_DBL)0;
223 int scale = mdctData_e + MDCT_OUT_HEADROOM -
224 LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside
225 multE2_DinvF_fdk() below */
226 int i;
227
228 /* Select LD window slope */
229 switch (N) {
230 case 256:
231 coef = LowDelaySynthesis256;
232 break;
233 case 240:
234 coef = LowDelaySynthesis240;
235 break;
236 case 160:
237 coef = LowDelaySynthesis160;
238 break;
239 case 128:
240 coef = LowDelaySynthesis128;
241 break;
242 case 120:
243 coef = LowDelaySynthesis120;
244 break;
245 case 512:
246 coef = LowDelaySynthesis512;
247 break;
248 case 480:
249 default:
250 coef = LowDelaySynthesis480;
251 break;
252 }
253
254 /*
255 Apply exponent and 1/N factor.
256 Note: "scale" is off by one because for LD_MDCT the window length is twice
257 the window length of a regular MDCT. This is corrected inside
258 multE2_DinvF_fdk(). Refer to ISO/IEC 14496-3:2009 page 277,
259 chapter 4.6.20.2 "Low Delay Window".
260 */
261 imdct_gain(&gain, &scale, N);
262
263 dct_IV(mdctData, N, &scale);
264
265 if (N == 256 || N == 240 || N == 160) {
266 scale -= 1;
267 } else if (N == 128 || N == 120) {
268 scale -= 2;
269 }
270
271 if (gain != (FIXP_DBL)0) {
272 for (i = 0; i < N; i++) {
273 mdctData[i] = fMult(mdctData[i], gain);
274 }
275 }
276 scaleValuesSaturate(mdctData, N, scale);
277
278 /* Since all exponent and factors have been applied, current exponent is zero.
279 */
280 multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N);
281
282 return (1);
283 }
284