diff options
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/float/apply_sine_window_FLP.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/float/apply_sine_window_FLP.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/float/apply_sine_window_FLP.c b/lib/rbcodec/codecs/libopus/silk/float/apply_sine_window_FLP.c new file mode 100644 index 0000000000..e49e717991 --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/float/apply_sine_window_FLP.c | |||
@@ -0,0 +1,81 @@ | |||
1 | /*********************************************************************** | ||
2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. | ||
3 | Redistribution and use in source and binary forms, with or without | ||
4 | modification, are permitted provided that the following conditions | ||
5 | are met: | ||
6 | - Redistributions of source code must retain the above copyright notice, | ||
7 | this list of conditions and the following disclaimer. | ||
8 | - Redistributions in binary form must reproduce the above copyright | ||
9 | notice, this list of conditions and the following disclaimer in the | ||
10 | documentation and/or other materials provided with the distribution. | ||
11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the | ||
12 | names of specific contributors, may be used to endorse or promote | ||
13 | products derived from this software without specific prior written | ||
14 | permission. | ||
15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | ||
16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | ||
19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | ||
20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | ||
21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | ||
22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | ||
23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | ||
24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
25 | POSSIBILITY OF SUCH DAMAGE. | ||
26 | ***********************************************************************/ | ||
27 | |||
28 | #ifdef HAVE_CONFIG_H | ||
29 | #include "config.h" | ||
30 | #endif | ||
31 | |||
32 | #include "main_FLP.h" | ||
33 | |||
34 | /* Apply sine window to signal vector */ | ||
35 | /* Window types: */ | ||
36 | /* 1 -> sine window from 0 to pi/2 */ | ||
37 | /* 2 -> sine window from pi/2 to pi */ | ||
38 | void silk_apply_sine_window_FLP( | ||
39 | silk_float px_win[], /* O Pointer to windowed signal */ | ||
40 | const silk_float px[], /* I Pointer to input signal */ | ||
41 | const opus_int win_type, /* I Selects a window type */ | ||
42 | const opus_int length /* I Window length, multiple of 4 */ | ||
43 | ) | ||
44 | { | ||
45 | opus_int k; | ||
46 | silk_float freq, c, S0, S1; | ||
47 | |||
48 | celt_assert( win_type == 1 || win_type == 2 ); | ||
49 | |||
50 | /* Length must be multiple of 4 */ | ||
51 | celt_assert( ( length & 3 ) == 0 ); | ||
52 | |||
53 | freq = PI / ( length + 1 ); | ||
54 | |||
55 | /* Approximation of 2 * cos(f) */ | ||
56 | c = 2.0f - freq * freq; | ||
57 | |||
58 | /* Initialize state */ | ||
59 | if( win_type < 2 ) { | ||
60 | /* Start from 0 */ | ||
61 | S0 = 0.0f; | ||
62 | /* Approximation of sin(f) */ | ||
63 | S1 = freq; | ||
64 | } else { | ||
65 | /* Start from 1 */ | ||
66 | S0 = 1.0f; | ||
67 | /* Approximation of cos(f) */ | ||
68 | S1 = 0.5f * c; | ||
69 | } | ||
70 | |||
71 | /* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */ | ||
72 | /* 4 samples at a time */ | ||
73 | for( k = 0; k < length; k += 4 ) { | ||
74 | px_win[ k + 0 ] = px[ k + 0 ] * 0.5f * ( S0 + S1 ); | ||
75 | px_win[ k + 1 ] = px[ k + 1 ] * S1; | ||
76 | S0 = c * S1 - S0; | ||
77 | px_win[ k + 2 ] = px[ k + 2 ] * 0.5f * ( S1 + S0 ); | ||
78 | px_win[ k + 3 ] = px[ k + 3 ] * S0; | ||
79 | S1 = c * S0 - S1; | ||
80 | } | ||
81 | } | ||