1 /*
2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11
12 /*
13 * This file contains the function WebRtcSpl_GetHanningWindow().
14 * The description header can be found in signal_processing_library.h
15 *
16 */
17
18 #include "common_audio/signal_processing/include/signal_processing_library.h"
19
20 // Hanning table with 256 entries
21 static const int16_t kHanningTable[] = {
22 1, 2, 6, 10, 15, 22, 30, 39,
23 50, 62, 75, 89, 104, 121, 138, 157,
24 178, 199, 222, 246, 271, 297, 324, 353,
25 383, 413, 446, 479, 513, 549, 586, 624,
26 663, 703, 744, 787, 830, 875, 920, 967,
27 1015, 1064, 1114, 1165, 1218, 1271, 1325, 1381,
28 1437, 1494, 1553, 1612, 1673, 1734, 1796, 1859,
29 1924, 1989, 2055, 2122, 2190, 2259, 2329, 2399,
30 2471, 2543, 2617, 2691, 2765, 2841, 2918, 2995,
31 3073, 3152, 3232, 3312, 3393, 3475, 3558, 3641,
32 3725, 3809, 3895, 3980, 4067, 4154, 4242, 4330,
33 4419, 4509, 4599, 4689, 4781, 4872, 4964, 5057,
34 5150, 5244, 5338, 5432, 5527, 5622, 5718, 5814,
35 5910, 6007, 6104, 6202, 6299, 6397, 6495, 6594,
36 6693, 6791, 6891, 6990, 7090, 7189, 7289, 7389,
37 7489, 7589, 7690, 7790, 7890, 7991, 8091, 8192,
38 8293, 8393, 8494, 8594, 8694, 8795, 8895, 8995,
39 9095, 9195, 9294, 9394, 9493, 9593, 9691, 9790,
40 9889, 9987, 10085, 10182, 10280, 10377, 10474, 10570,
41 10666, 10762, 10857, 10952, 11046, 11140, 11234, 11327,
42 11420, 11512, 11603, 11695, 11785, 11875, 11965, 12054,
43 12142, 12230, 12317, 12404, 12489, 12575, 12659, 12743,
44 12826, 12909, 12991, 13072, 13152, 13232, 13311, 13389,
45 13466, 13543, 13619, 13693, 13767, 13841, 13913, 13985,
46 14055, 14125, 14194, 14262, 14329, 14395, 14460, 14525,
47 14588, 14650, 14711, 14772, 14831, 14890, 14947, 15003,
48 15059, 15113, 15166, 15219, 15270, 15320, 15369, 15417,
49 15464, 15509, 15554, 15597, 15640, 15681, 15721, 15760,
50 15798, 15835, 15871, 15905, 15938, 15971, 16001, 16031,
51 16060, 16087, 16113, 16138, 16162, 16185, 16206, 16227,
52 16246, 16263, 16280, 16295, 16309, 16322, 16334, 16345,
53 16354, 16362, 16369, 16374, 16378, 16382, 16383, 16384
54 };
55
WebRtcSpl_GetHanningWindow(int16_t * v,size_t size)56 void WebRtcSpl_GetHanningWindow(int16_t *v, size_t size)
57 {
58 size_t jj;
59 int16_t *vptr1;
60
61 int32_t index;
62 int32_t factor = ((int32_t)0x40000000);
63
64 factor = WebRtcSpl_DivW32W16(factor, (int16_t)size);
65 if (size < 513)
66 index = (int32_t)-0x200000;
67 else
68 index = (int32_t)-0x100000;
69 vptr1 = v;
70
71 for (jj = 0; jj < size; jj++)
72 {
73 index += factor;
74 (*vptr1++) = kHanningTable[index >> 22];
75 }
76
77 }
78