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Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/NLSF_stabilize.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/NLSF_stabilize.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/NLSF_stabilize.c b/lib/rbcodec/codecs/libopus/silk/NLSF_stabilize.c new file mode 100644 index 0000000000..25ec49f4c1 --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/NLSF_stabilize.c | |||
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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 "opus_config.h" | ||
30 | #endif | ||
31 | |||
32 | /* NLSF stabilizer: */ | ||
33 | /* */ | ||
34 | /* - Moves NLSFs futher apart if they are too close */ | ||
35 | /* - Moves NLSFs away from borders if they are too close */ | ||
36 | /* - High effort to achieve a modification with minimum */ | ||
37 | /* Euclidean distance to input vector */ | ||
38 | /* - Output are sorted NLSF coefficients */ | ||
39 | /* */ | ||
40 | |||
41 | #include "SigProc_FIX.h" | ||
42 | |||
43 | /* Constant Definitions */ | ||
44 | #define MAX_LOOPS 20 | ||
45 | |||
46 | /* NLSF stabilizer, for a single input data vector */ | ||
47 | void silk_NLSF_stabilize( | ||
48 | opus_int16 *NLSF_Q15, /* I/O Unstable/stabilized normalized LSF vector in Q15 [L] */ | ||
49 | const opus_int16 *NDeltaMin_Q15, /* I Min distance vector, NDeltaMin_Q15[L] must be >= 1 [L+1] */ | ||
50 | const opus_int L /* I Number of NLSF parameters in the input vector */ | ||
51 | ) | ||
52 | { | ||
53 | opus_int i, I=0, k, loops; | ||
54 | opus_int16 center_freq_Q15; | ||
55 | opus_int32 diff_Q15, min_diff_Q15, min_center_Q15, max_center_Q15; | ||
56 | |||
57 | /* This is necessary to ensure an output within range of a opus_int16 */ | ||
58 | silk_assert( NDeltaMin_Q15[L] >= 1 ); | ||
59 | |||
60 | for( loops = 0; loops < MAX_LOOPS; loops++ ) { | ||
61 | /**************************/ | ||
62 | /* Find smallest distance */ | ||
63 | /**************************/ | ||
64 | /* First element */ | ||
65 | min_diff_Q15 = NLSF_Q15[0] - NDeltaMin_Q15[0]; | ||
66 | I = 0; | ||
67 | /* Middle elements */ | ||
68 | for( i = 1; i <= L-1; i++ ) { | ||
69 | diff_Q15 = NLSF_Q15[i] - ( NLSF_Q15[i-1] + NDeltaMin_Q15[i] ); | ||
70 | if( diff_Q15 < min_diff_Q15 ) { | ||
71 | min_diff_Q15 = diff_Q15; | ||
72 | I = i; | ||
73 | } | ||
74 | } | ||
75 | /* Last element */ | ||
76 | diff_Q15 = ( 1 << 15 ) - ( NLSF_Q15[L-1] + NDeltaMin_Q15[L] ); | ||
77 | if( diff_Q15 < min_diff_Q15 ) { | ||
78 | min_diff_Q15 = diff_Q15; | ||
79 | I = L; | ||
80 | } | ||
81 | |||
82 | /***************************************************/ | ||
83 | /* Now check if the smallest distance non-negative */ | ||
84 | /***************************************************/ | ||
85 | if( min_diff_Q15 >= 0 ) { | ||
86 | return; | ||
87 | } | ||
88 | |||
89 | if( I == 0 ) { | ||
90 | /* Move away from lower limit */ | ||
91 | NLSF_Q15[0] = NDeltaMin_Q15[0]; | ||
92 | |||
93 | } else if( I == L) { | ||
94 | /* Move away from higher limit */ | ||
95 | NLSF_Q15[L-1] = ( 1 << 15 ) - NDeltaMin_Q15[L]; | ||
96 | |||
97 | } else { | ||
98 | /* Find the lower extreme for the location of the current center frequency */ | ||
99 | min_center_Q15 = 0; | ||
100 | for( k = 0; k < I; k++ ) { | ||
101 | min_center_Q15 += NDeltaMin_Q15[k]; | ||
102 | } | ||
103 | min_center_Q15 += silk_RSHIFT( NDeltaMin_Q15[I], 1 ); | ||
104 | |||
105 | /* Find the upper extreme for the location of the current center frequency */ | ||
106 | max_center_Q15 = 1 << 15; | ||
107 | for( k = L; k > I; k-- ) { | ||
108 | max_center_Q15 -= NDeltaMin_Q15[k]; | ||
109 | } | ||
110 | max_center_Q15 -= silk_RSHIFT( NDeltaMin_Q15[I], 1 ); | ||
111 | |||
112 | /* Move apart, sorted by value, keeping the same center frequency */ | ||
113 | center_freq_Q15 = (opus_int16)silk_LIMIT_32( silk_RSHIFT_ROUND( (opus_int32)NLSF_Q15[I-1] + (opus_int32)NLSF_Q15[I], 1 ), | ||
114 | min_center_Q15, max_center_Q15 ); | ||
115 | NLSF_Q15[I-1] = center_freq_Q15 - silk_RSHIFT( NDeltaMin_Q15[I], 1 ); | ||
116 | NLSF_Q15[I] = NLSF_Q15[I-1] + NDeltaMin_Q15[I]; | ||
117 | } | ||
118 | } | ||
119 | |||
120 | /* Safe and simple fall back method, which is less ideal than the above */ | ||
121 | if( loops == MAX_LOOPS ) | ||
122 | { | ||
123 | /* Insertion sort (fast for already almost sorted arrays): */ | ||
124 | /* Best case: O(n) for an already sorted array */ | ||
125 | /* Worst case: O(n^2) for an inversely sorted array */ | ||
126 | silk_insertion_sort_increasing_all_values_int16( &NLSF_Q15[0], L ); | ||
127 | |||
128 | /* First NLSF should be no less than NDeltaMin[0] */ | ||
129 | NLSF_Q15[0] = silk_max_int( NLSF_Q15[0], NDeltaMin_Q15[0] ); | ||
130 | |||
131 | /* Keep delta_min distance between the NLSFs */ | ||
132 | for( i = 1; i < L; i++ ) | ||
133 | NLSF_Q15[i] = silk_max_int( NLSF_Q15[i], NLSF_Q15[i-1] + NDeltaMin_Q15[i] ); | ||
134 | |||
135 | /* Last NLSF should be no higher than 1 - NDeltaMin[L] */ | ||
136 | NLSF_Q15[L-1] = silk_min_int( NLSF_Q15[L-1], (1<<15) - NDeltaMin_Q15[L] ); | ||
137 | |||
138 | /* Keep NDeltaMin distance between the NLSFs */ | ||
139 | for( i = L-2; i >= 0; i-- ) | ||
140 | NLSF_Q15[i] = silk_min_int( NLSF_Q15[i], NLSF_Q15[i+1] - NDeltaMin_Q15[i+1] ); | ||
141 | } | ||
142 | } | ||