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: decim54.c *
19 * *
20 * Description:Decimation of 16kHz signal to 12.8kHz *
21 * *
22 ************************************************************************/
23
24 #include "typedef.h"
25 #include "basic_op.h"
26 #include "acelp.h"
27 #include "cnst.h"
28
29 #define FAC5 5
30 #define DOWN_FAC 26215 /* 4/5 in Q15 */
31
32 #define NB_COEF_DOWN 15
33
34 /* Local functions */
35 static void Down_samp(
36 Word16 * sig, /* input: signal to downsampling */
37 Word16 * sig_d, /* output: downsampled signal */
38 Word16 L_frame_d /* input: length of output */
39 );
40
41 /* 1/5 resolution interpolation filter (in Q14) */
42 /* -1.5dB @ 6kHz, -6dB @ 6.4kHz, -10dB @ 6.6kHz, -20dB @ 6.9kHz, -25dB @ 7kHz, -55dB @ 8kHz */
43
44 static Word16 fir_down1[4][30] =
45 {
46 {-5, 24, -50, 54, 0, -128, 294, -408, 344, 0, -647, 1505, -2379, 3034, 13107, 3034, -2379, 1505, -647, 0, 344, -408,
47 294, -128, 0, 54, -50, 24, -5, 0},
48
49 {-6, 19, -26, 0, 77, -188, 270, -233, 0, 434, -964, 1366, -1293, 0, 12254, 6575, -2746, 1030, 0, -507, 601, -441,
50 198, 0, -95, 99, -58, 18, 0, -1},
51
52 {-3, 9, 0, -41, 111, -170, 153, 0, -295, 649, -888, 770, 0, -1997, 9894, 9894, -1997, 0, 770, -888, 649, -295, 0,
53 153, -170, 111, -41, 0, 9, -3},
54
55 {-1, 0, 18, -58, 99, -95, 0, 198, -441, 601, -507, 0, 1030, -2746, 6575, 12254, 0, -1293, 1366, -964, 434, 0,
56 -233, 270, -188, 77, 0, -26, 19, -6}
57 };
58
Init_Decim_12k8(Word16 mem[])59 void Init_Decim_12k8(
60 Word16 mem[] /* output: memory (2*NB_COEF_DOWN) set to zeros */
61 )
62 {
63 Set_zero(mem, 2 * NB_COEF_DOWN);
64 return;
65 }
66
Decim_12k8(Word16 sig16k[],Word16 lg,Word16 sig12k8[],Word16 mem[])67 void Decim_12k8(
68 Word16 sig16k[], /* input: signal to downsampling */
69 Word16 lg, /* input: length of input */
70 Word16 sig12k8[], /* output: decimated signal */
71 Word16 mem[] /* in/out: memory (2*NB_COEF_DOWN) */
72 )
73 {
74 Word16 lg_down;
75 Word16 signal[L_FRAME16k + (2 * NB_COEF_DOWN)];
76
77 Copy(mem, signal, 2 * NB_COEF_DOWN);
78
79 Copy(sig16k, signal + (2 * NB_COEF_DOWN), lg);
80
81 lg_down = (lg * DOWN_FAC)>>15;
82
83 Down_samp(signal + NB_COEF_DOWN, sig12k8, lg_down);
84
85 Copy(signal + lg, mem, 2 * NB_COEF_DOWN);
86
87 return;
88 }
89
Down_samp(Word16 * sig,Word16 * sig_d,Word16 L_frame_d)90 static void Down_samp(
91 Word16 * sig, /* input: signal to downsampling */
92 Word16 * sig_d, /* output: downsampled signal */
93 Word16 L_frame_d /* input: length of output */
94 )
95 {
96 Word32 i, j, frac, pos;
97 Word16 *x, *y;
98 Word32 L_sum;
99
100 pos = 0; /* position is in Q2 -> 1/4 resolution */
101 for (j = 0; j < L_frame_d; j++)
102 {
103 i = (pos >> 2); /* integer part */
104 frac = pos & 3; /* fractional part */
105 x = sig + i - NB_COEF_DOWN + 1;
106 y = (Word16 *)(fir_down1 + frac);
107
108 L_sum = vo_mult32((*x++),(*y++));
109 L_sum += vo_mult32((*x++),(*y++));
110 L_sum += vo_mult32((*x++),(*y++));
111 L_sum += vo_mult32((*x++),(*y++));
112 L_sum += vo_mult32((*x++),(*y++));
113 L_sum += vo_mult32((*x++),(*y++));
114 L_sum += vo_mult32((*x++),(*y++));
115 L_sum += vo_mult32((*x++),(*y++));
116 L_sum += vo_mult32((*x++),(*y++));
117 L_sum += vo_mult32((*x++),(*y++));
118 L_sum += vo_mult32((*x++),(*y++));
119 L_sum += vo_mult32((*x++),(*y++));
120 L_sum += vo_mult32((*x++),(*y++));
121 L_sum += vo_mult32((*x++),(*y++));
122 L_sum += vo_mult32((*x++),(*y++));
123 L_sum += vo_mult32((*x++),(*y++));
124 L_sum += vo_mult32((*x++),(*y++));
125 L_sum += vo_mult32((*x++),(*y++));
126 L_sum += vo_mult32((*x++),(*y++));
127 L_sum += vo_mult32((*x++),(*y++));
128 L_sum += vo_mult32((*x++),(*y++));
129 L_sum += vo_mult32((*x++),(*y++));
130 L_sum += vo_mult32((*x++),(*y++));
131 L_sum += vo_mult32((*x++),(*y++));
132 L_sum += vo_mult32((*x++),(*y++));
133 L_sum += vo_mult32((*x++),(*y++));
134 L_sum += vo_mult32((*x++),(*y++));
135 L_sum += vo_mult32((*x++),(*y++));
136 L_sum += vo_mult32((*x++),(*y++));
137 L_sum += vo_mult32((*x),(*y));
138
139 L_sum = L_shl2(L_sum, 2);
140 sig_d[j] = extract_h(L_add(L_sum, 0x8000));
141 pos += FAC5; /* pos + 5/4 */
142 }
143 return;
144 }
145
146
147