1 
2 /* -----------------------------------------------------------------------------------------------------------
3 Software License for The Fraunhofer FDK AAC Codec Library for Android
4 
5 � Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.
6   All rights reserved.
7 
8  1.    INTRODUCTION
9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
12 
13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
16 of the MPEG specifications.
17 
18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
20 individually for the purpose of encoding or decoding bit streams in products that are compliant with
21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
23 software may already be covered under those patent licenses when it is used for those licensed purposes only.
24 
25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
27 applications information and documentation.
28 
29 2.    COPYRIGHT LICENSE
30 
31 Redistribution and use in source and binary forms, with or without modification, are permitted without
32 payment of copyright license fees provided that you satisfy the following conditions:
33 
34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
35 your modifications thereto in source code form.
36 
37 You must retain the complete text of this software license in the documentation and/or other materials
38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
40 modifications thereto to recipients of copies in binary form.
41 
42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without
43 prior written permission.
44 
45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
46 software or your modifications thereto.
47 
48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
49 and the date of any change. For modified versions of the FDK AAC Codec, the term
50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
52 
53 3.    NO PATENT LICENSE
54 
55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
57 respect to this software.
58 
59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
60 by appropriate patent licenses.
61 
62 4.    DISCLAIMER
63 
64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
69 or business interruption, however caused and on any theory of liability, whether in contract, strict
70 liability, or tort (including negligence), arising in any way out of the use of this software, even if
71 advised of the possibility of such damage.
72 
73 5.    CONTACT INFORMATION
74 
75 Fraunhofer Institute for Integrated Circuits IIS
76 Attention: Audio and Multimedia Departments - FDK AAC LL
77 Am Wolfsmantel 33
78 91058 Erlangen, Germany
79 
80 www.iis.fraunhofer.de/amm
81 amm-info@iis.fraunhofer.de
82 ----------------------------------------------------------------------------------------------------------- */
83 
84 /***************************************************************************\
85 *
86  *   filename: ldfiltbank.c
87  *   project : MPEG-4 Audio Decoder
88  *   contents/description: low delay filterbank
89  *
90 \***************************************************************************/
91 
92 #include "ldfiltbank.h"
93 
94 
95 #include "aac_rom.h"
96 #include "dct.h"
97 #include "FDK_tools_rom.h"
98 #include "mdct.h"
99 
100 #define LDFB_HEADROOM 2
101 
multE2_DinvF_fdk(INT_PCM * output,FIXP_DBL * x,const FIXP_WTB * fb,FIXP_DBL * z,const int N,const int stride)102 static void multE2_DinvF_fdk(INT_PCM *output, FIXP_DBL* x, const FIXP_WTB* fb, FIXP_DBL* z, const int N, const int  stride)
103 {
104   int i, scale;
105 
106   /*  scale for FIXP_DBL -> INT_PCM conversion. */
107   scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM;
108 
109   for(i=0;i<N/4;i++)
110   {
111     FIXP_DBL z0, z2, tmp;
112 
113     z2 = x[N/2+i];
114     z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) );
115 
116     z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) );
117 
118     tmp = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ;
119 
120 #if (SAMPLE_BITS <= 16)
121     FDK_ASSERT( (-WTS1-1 + scale) >= 0);
122     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp, -WTS1-1 + scale, SAMPLE_BITS);
123 #else
124     FDK_ASSERT( (WTS1+1 - scale) >= 0);
125     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1+1 - scale, SAMPLE_BITS);
126 #endif
127 
128     z[i] = z0;
129     z[N + i] = z2;
130   }
131 
132   for(i=N/4;i<N/2;i++)
133   {
134     FIXP_DBL z0, z2, tmp0, tmp1;
135 
136     z2 = x[N/2+i];
137     z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) );
138 
139     z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) );
140 
141     tmp0 = ( fMultDiv2(z[N/2+i], fb[N/2-1-i])   + fMultDiv2(z[i], fb[N/2+i])   ) ;
142     tmp1 = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ;
143 
144 #if (SAMPLE_BITS <= 16)
145     FDK_ASSERT( (-WTS0-1 + scale) >= 0);
146     output[(i-N/4)*stride]     = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS);
147     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp1, -WTS1-1 + scale, SAMPLE_BITS);
148 #else
149     FDK_ASSERT( (WTS0+1 - scale) >= 0);
150     output[(i-N/4)*stride]     = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS);
151     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1+1 - scale, SAMPLE_BITS);
152 #endif
153     z[i] = z0;
154     z[N + i] = z2;
155   }
156 
157   /* Exchange quarter parts of x to bring them in the "right" order */
158   for(i=0;i<N/4;i++)
159   {
160     FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N/2+i]);
161 
162 #if (SAMPLE_BITS <= 16)
163     FDK_ASSERT( (-WTS0-1 + scale) >= 0);
164     output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS);
165 #else
166     FDK_ASSERT( (WTS0+1 - scale) >= 0);
167     output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS);
168 #endif
169   }
170 }
171 
InvMdctTransformLowDelay_fdk(FIXP_DBL * mdctData,const int mdctData_e,INT_PCM * output,FIXP_DBL * fs_buffer,const int stride,const int N)172 int InvMdctTransformLowDelay_fdk (FIXP_DBL *mdctData, const int mdctData_e, INT_PCM *output, FIXP_DBL *fs_buffer, const int stride, const int N) {
173 
174   const FIXP_WTB *coef;
175   FIXP_DBL gain = (FIXP_DBL)0;
176   int scale = mdctData_e + MDCT_OUT_HEADROOM - LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside multE2_DinvF_fdk() below */
177 
178   /* Select LD window slope */
179   if (N == 512)
180     coef = (FIXP_WTB*)LowDelaySynthesis512;
181   else
182     coef = (FIXP_WTB*)LowDelaySynthesis480;
183 
184   /*
185      Apply exponent and 1/N factor.
186      Note: "scale" is off by one because for LD_MDCT the window length is twice
187      the window length of a regular MDCT. This is corrected inside multE2_DinvF_fdk().
188      Refer to ISO/IEC 14496-3:2009 page 277, chapter 4.6.20.2 "Low Delay Window".
189    */
190   imdct_gain(&gain, &scale, N);
191 
192   dct_IV(mdctData, N, &scale);
193 
194   if (gain != (FIXP_DBL)0) {
195     scaleValuesWithFactor(mdctData, gain, N, scale);
196   } else {
197     scaleValues(mdctData, N, scale);
198   }
199 
200   /* Since all exponent and factors have been applied, current exponent is zero. */
201   multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N, stride);
202 
203   return (1);
204 }
205 
206 
207 
208 
209