1 /*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 ** http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17 /***********************************************************************
18 * File: pred_lt4.c *
19 * *
20 * Description: Compute the result of long term prediction with *
21 * fractional interpolation of resolution 1/4 *
22 * on return exc[0..L_subr-1] contains the interpolated signal *
23 * (adaptive codebook excitation) *
24 * *
25 ************************************************************************/
26
27 #include "typedef.h"
28 #include "basic_op.h"
29
30 #define UP_SAMP 4
31 #define L_INTERPOL2 16
32
33 /* 1/4 resolution interpolation filter (-3 dB at 0.856*fs/2) in Q14 */
34
35 Word16 inter4_2[4][32] =
36 {
37 {0,-2,4,-2,-10,38,-88,165,-275,424,-619,871,-1207,1699,-2598,5531,14031,-2147,780,-249,
38 -16,153,-213,226,-209,175,-133,91,-55,28,-10,2},
39
40 {1,-7,19,-33,47,-52,43,-9,-60,175,-355,626,-1044,1749,-3267,10359,10359,-3267,1749,-1044,
41 626,-355,175,-60,-9,43,-52,47,-33,19, -7, 1},
42
43 {2,-10,28,-55,91,-133,175,-209,226,-213,153,-16,-249,780,-2147,14031,5531,-2598,1699,-1207,
44 871,-619,424,-275,165,-88,38,-10,-2,4,-2,0},
45
46 {1,-7,22,-49,92,-153,231,-325,431,-544,656,-762,853,-923,968,15401,968,-923,853,-762,
47 656,-544,431,-325,231,-153,92,-49,22,-7, 1, 0}
48
49 };
50
Pred_lt4(Word16 exc[],Word16 T0,Word16 frac,Word16 L_subfr)51 void Pred_lt4(
52 Word16 exc[], /* in/out: excitation buffer */
53 Word16 T0, /* input : integer pitch lag */
54 Word16 frac, /* input : fraction of lag */
55 Word16 L_subfr /* input : subframe size */
56 )
57 {
58 Word16 j, k, *x;
59 Word32 L_sum;
60 Word16 *ptr, *ptr1;
61 Word16 *ptr2;
62
63 x = exc - T0;
64 frac = -frac;
65 if (frac < 0)
66 {
67 frac += UP_SAMP;
68 x--;
69 }
70 x -= 15; /* x = L_INTERPOL2 - 1 */
71 k = 3 - frac; /* k = UP_SAMP - 1 - frac */
72
73 ptr2 = &(inter4_2[k][0]);
74 for (j = 0; j < L_subfr; j++)
75 {
76 ptr = ptr2;
77 ptr1 = x;
78 L_sum = vo_mult32((*ptr1++), (*ptr++));
79 L_sum += vo_mult32((*ptr1++), (*ptr++));
80 L_sum += vo_mult32((*ptr1++), (*ptr++));
81 L_sum += vo_mult32((*ptr1++), (*ptr++));
82 L_sum += vo_mult32((*ptr1++), (*ptr++));
83 L_sum += vo_mult32((*ptr1++), (*ptr++));
84 L_sum += vo_mult32((*ptr1++), (*ptr++));
85 L_sum += vo_mult32((*ptr1++), (*ptr++));
86 L_sum += vo_mult32((*ptr1++), (*ptr++));
87 L_sum += vo_mult32((*ptr1++), (*ptr++));
88 L_sum += vo_mult32((*ptr1++), (*ptr++));
89 L_sum += vo_mult32((*ptr1++), (*ptr++));
90 L_sum += vo_mult32((*ptr1++), (*ptr++));
91 L_sum += vo_mult32((*ptr1++), (*ptr++));
92 L_sum += vo_mult32((*ptr1++), (*ptr++));
93 L_sum += vo_mult32((*ptr1++), (*ptr++));
94 L_sum += vo_mult32((*ptr1++), (*ptr++));
95 L_sum += vo_mult32((*ptr1++), (*ptr++));
96 L_sum += vo_mult32((*ptr1++), (*ptr++));
97 L_sum += vo_mult32((*ptr1++), (*ptr++));
98 L_sum += vo_mult32((*ptr1++), (*ptr++));
99 L_sum += vo_mult32((*ptr1++), (*ptr++));
100 L_sum += vo_mult32((*ptr1++), (*ptr++));
101 L_sum += vo_mult32((*ptr1++), (*ptr++));
102 L_sum += vo_mult32((*ptr1++), (*ptr++));
103 L_sum += vo_mult32((*ptr1++), (*ptr++));
104 L_sum += vo_mult32((*ptr1++), (*ptr++));
105 L_sum += vo_mult32((*ptr1++), (*ptr++));
106 L_sum += vo_mult32((*ptr1++), (*ptr++));
107 L_sum += vo_mult32((*ptr1++), (*ptr++));
108 L_sum += vo_mult32((*ptr1++), (*ptr++));
109 L_sum += vo_mult32((*ptr1++), (*ptr++));
110
111 L_sum = L_shl2(L_sum, 2);
112 exc[j] = extract_h(L_add(L_sum, 0x8000));
113 x++;
114 }
115
116 return;
117 }
118
119
120
121