Line data Source code
1 : /***********************************************************************
2 : Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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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
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14 : permission.
15 : THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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17 : IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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19 : LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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22 : INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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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.h"
33 :
34 : #define OFFSET ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 )
35 : #define SCALE_Q16 ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) )
36 : #define INV_SCALE_Q16 ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) )
37 :
38 : /* Gain scalar quantization with hysteresis, uniform on log scale */
39 0 : void silk_gains_quant(
40 : opus_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */
41 : opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */
42 : opus_int8 *prev_ind, /* I/O last index in previous frame */
43 : const opus_int conditional, /* I first gain is delta coded if 1 */
44 : const opus_int nb_subfr /* I number of subframes */
45 : )
46 : {
47 : opus_int k, double_step_size_threshold;
48 :
49 0 : for( k = 0; k < nb_subfr; k++ ) {
50 : /* Convert to log scale, scale, floor() */
51 0 : ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET );
52 :
53 : /* Round towards previous quantized gain (hysteresis) */
54 0 : if( ind[ k ] < *prev_ind ) {
55 0 : ind[ k ]++;
56 : }
57 0 : ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
58 :
59 : /* Compute delta indices and limit */
60 0 : if( k == 0 && conditional == 0 ) {
61 : /* Full index */
62 0 : ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
63 0 : *prev_ind = ind[ k ];
64 : } else {
65 : /* Delta index */
66 0 : ind[ k ] = ind[ k ] - *prev_ind;
67 :
68 : /* Double the quantization step size for large gain increases, so that the max gain level can be reached */
69 0 : double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
70 0 : if( ind[ k ] > double_step_size_threshold ) {
71 0 : ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
72 : }
73 :
74 0 : ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
75 :
76 : /* Accumulate deltas */
77 0 : if( ind[ k ] > double_step_size_threshold ) {
78 0 : *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
79 0 : *prev_ind = silk_min_int( *prev_ind, N_LEVELS_QGAIN - 1 );
80 : } else {
81 0 : *prev_ind += ind[ k ];
82 : }
83 :
84 : /* Shift to make non-negative */
85 0 : ind[ k ] -= MIN_DELTA_GAIN_QUANT;
86 : }
87 :
88 : /* Scale and convert to linear scale */
89 0 : gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
90 : }
91 0 : }
92 :
93 : /* Gains scalar dequantization, uniform on log scale */
94 0 : void silk_gains_dequant(
95 : opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */
96 : const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
97 : opus_int8 *prev_ind, /* I/O last index in previous frame */
98 : const opus_int conditional, /* I first gain is delta coded if 1 */
99 : const opus_int nb_subfr /* I number of subframes */
100 : )
101 : {
102 : opus_int k, ind_tmp, double_step_size_threshold;
103 :
104 0 : for( k = 0; k < nb_subfr; k++ ) {
105 0 : if( k == 0 && conditional == 0 ) {
106 : /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */
107 0 : *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 );
108 : } else {
109 : /* Delta index */
110 0 : ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT;
111 :
112 : /* Accumulate deltas */
113 0 : double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
114 0 : if( ind_tmp > double_step_size_threshold ) {
115 0 : *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold;
116 : } else {
117 0 : *prev_ind += ind_tmp;
118 : }
119 : }
120 0 : *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 );
121 :
122 : /* Scale and convert to linear scale */
123 0 : gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
124 : }
125 0 : }
126 :
127 : /* Compute unique identifier of gain indices vector */
128 0 : opus_int32 silk_gains_ID( /* O returns unique identifier of gains */
129 : const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
130 : const opus_int nb_subfr /* I number of subframes */
131 : )
132 : {
133 : opus_int k;
134 : opus_int32 gainsID;
135 :
136 0 : gainsID = 0;
137 0 : for( k = 0; k < nb_subfr; k++ ) {
138 0 : gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
139 : }
140 :
141 0 : return gainsID;
142 : }
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