diff options
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/LP_variable_cutoff.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/LP_variable_cutoff.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/LP_variable_cutoff.c b/lib/rbcodec/codecs/libopus/silk/LP_variable_cutoff.c new file mode 100644 index 0000000000..79112ad354 --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/LP_variable_cutoff.c | |||
@@ -0,0 +1,135 @@ | |||
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 | /* | ||
33 | Elliptic/Cauer filters designed with 0.1 dB passband ripple, | ||
34 | 80 dB minimum stopband attenuation, and | ||
35 | [0.95 : 0.15 : 0.35] normalized cut off frequencies. | ||
36 | */ | ||
37 | |||
38 | #include "main.h" | ||
39 | |||
40 | /* Helper function, interpolates the filter taps */ | ||
41 | static OPUS_INLINE void silk_LP_interpolate_filter_taps( | ||
42 | opus_int32 B_Q28[ TRANSITION_NB ], | ||
43 | opus_int32 A_Q28[ TRANSITION_NA ], | ||
44 | const opus_int ind, | ||
45 | const opus_int32 fac_Q16 | ||
46 | ) | ||
47 | { | ||
48 | opus_int nb, na; | ||
49 | |||
50 | if( ind < TRANSITION_INT_NUM - 1 ) { | ||
51 | if( fac_Q16 > 0 ) { | ||
52 | if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */ | ||
53 | /* Piece-wise linear interpolation of B and A */ | ||
54 | for( nb = 0; nb < TRANSITION_NB; nb++ ) { | ||
55 | B_Q28[ nb ] = silk_SMLAWB( | ||
56 | silk_Transition_LP_B_Q28[ ind ][ nb ], | ||
57 | silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - | ||
58 | silk_Transition_LP_B_Q28[ ind ][ nb ], | ||
59 | fac_Q16 ); | ||
60 | } | ||
61 | for( na = 0; na < TRANSITION_NA; na++ ) { | ||
62 | A_Q28[ na ] = silk_SMLAWB( | ||
63 | silk_Transition_LP_A_Q28[ ind ][ na ], | ||
64 | silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - | ||
65 | silk_Transition_LP_A_Q28[ ind ][ na ], | ||
66 | fac_Q16 ); | ||
67 | } | ||
68 | } else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */ | ||
69 | silk_assert( fac_Q16 - ( 1 << 16 ) == silk_SAT16( fac_Q16 - ( 1 << 16 ) ) ); | ||
70 | /* Piece-wise linear interpolation of B and A */ | ||
71 | for( nb = 0; nb < TRANSITION_NB; nb++ ) { | ||
72 | B_Q28[ nb ] = silk_SMLAWB( | ||
73 | silk_Transition_LP_B_Q28[ ind + 1 ][ nb ], | ||
74 | silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - | ||
75 | silk_Transition_LP_B_Q28[ ind ][ nb ], | ||
76 | fac_Q16 - ( (opus_int32)1 << 16 ) ); | ||
77 | } | ||
78 | for( na = 0; na < TRANSITION_NA; na++ ) { | ||
79 | A_Q28[ na ] = silk_SMLAWB( | ||
80 | silk_Transition_LP_A_Q28[ ind + 1 ][ na ], | ||
81 | silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - | ||
82 | silk_Transition_LP_A_Q28[ ind ][ na ], | ||
83 | fac_Q16 - ( (opus_int32)1 << 16 ) ); | ||
84 | } | ||
85 | } | ||
86 | } else { | ||
87 | silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( opus_int32 ) ); | ||
88 | silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( opus_int32 ) ); | ||
89 | } | ||
90 | } else { | ||
91 | silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( opus_int32 ) ); | ||
92 | silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( opus_int32 ) ); | ||
93 | } | ||
94 | } | ||
95 | |||
96 | /* Low-pass filter with variable cutoff frequency based on */ | ||
97 | /* piece-wise linear interpolation between elliptic filters */ | ||
98 | /* Start by setting psEncC->mode <> 0; */ | ||
99 | /* Deactivate by setting psEncC->mode = 0; */ | ||
100 | void silk_LP_variable_cutoff( | ||
101 | silk_LP_state *psLP, /* I/O LP filter state */ | ||
102 | opus_int16 *frame, /* I/O Low-pass filtered output signal */ | ||
103 | const opus_int frame_length /* I Frame length */ | ||
104 | ) | ||
105 | { | ||
106 | opus_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0; | ||
107 | opus_int ind = 0; | ||
108 | |||
109 | silk_assert( psLP->transition_frame_no >= 0 && psLP->transition_frame_no <= TRANSITION_FRAMES ); | ||
110 | |||
111 | /* Run filter if needed */ | ||
112 | if( psLP->mode != 0 ) { | ||
113 | /* Calculate index and interpolation factor for interpolation */ | ||
114 | #if( TRANSITION_INT_STEPS == 64 ) | ||
115 | fac_Q16 = silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 - 6 ); | ||
116 | #else | ||
117 | fac_Q16 = silk_DIV32_16( silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 ), TRANSITION_FRAMES ); | ||
118 | #endif | ||
119 | ind = silk_RSHIFT( fac_Q16, 16 ); | ||
120 | fac_Q16 -= silk_LSHIFT( ind, 16 ); | ||
121 | |||
122 | silk_assert( ind >= 0 ); | ||
123 | silk_assert( ind < TRANSITION_INT_NUM ); | ||
124 | |||
125 | /* Interpolate filter coefficients */ | ||
126 | silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 ); | ||
127 | |||
128 | /* Update transition frame number for next frame */ | ||
129 | psLP->transition_frame_no = silk_LIMIT( psLP->transition_frame_no + psLP->mode, 0, TRANSITION_FRAMES ); | ||
130 | |||
131 | /* ARMA low-pass filtering */ | ||
132 | silk_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 ); | ||
133 | silk_biquad_alt_stride1( frame, B_Q28, A_Q28, psLP->In_LP_State, frame, frame_length); | ||
134 | } | ||
135 | } | ||