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comparison: media/libopus/silk/gain_quant.c
media/libopus/silk/gain_quant.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 "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 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 for( k = 0; k < nb_subfr; k++ ) { | |
| 50 /* Convert to log scale, scale, floor() */ | |
| 51 ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET ); | |
| 52 | |
| 53 /* Round towards previous quantized gain (hysteresis) */ | |
| 54 if( ind[ k ] < *prev_ind ) { | |
| 55 ind[ k ]++; | |
| 56 } | |
| 57 ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 ); | |
| 58 | |
| 59 /* Compute delta indices and limit */ | |
| 60 if( k == 0 && conditional == 0 ) { | |
| 61 /* Full index */ | |
| 62 ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 ); | |
| 63 *prev_ind = ind[ k ]; | |
| 64 } else { | |
| 65 /* Delta index */ | |
| 66 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 double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind; | |
| 70 if( ind[ k ] > double_step_size_threshold ) { | |
| 71 ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 ); | |
| 72 } | |
| 73 | |
| 74 ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT ); | |
| 75 | |
| 76 /* Accumulate deltas */ | |
| 77 if( ind[ k ] > double_step_size_threshold ) { | |
| 78 *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold; | |
| 79 } else { | |
| 80 *prev_ind += ind[ k ]; | |
| 81 } | |
| 82 | |
| 83 /* Shift to make non-negative */ | |
| 84 ind[ k ] -= MIN_DELTA_GAIN_QUANT; | |
| 85 } | |
| 86 | |
| 87 /* Scale and convert to linear scale */ | |
| 88 gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */ | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 /* Gains scalar dequantization, uniform on log scale */ | |
| 93 void silk_gains_dequant( | |
| 94 opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */ | |
| 95 const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */ | |
| 96 opus_int8 *prev_ind, /* I/O last index in previous frame */ | |
| 97 const opus_int conditional, /* I first gain is delta coded if 1 */ | |
| 98 const opus_int nb_subfr /* I number of subframes */ | |
| 99 ) | |
| 100 { | |
| 101 opus_int k, ind_tmp, double_step_size_threshold; | |
| 102 | |
| 103 for( k = 0; k < nb_subfr; k++ ) { | |
| 104 if( k == 0 && conditional == 0 ) { | |
| 105 /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */ | |
| 106 *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 ); | |
| 107 } else { | |
| 108 /* Delta index */ | |
| 109 ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT; | |
| 110 | |
| 111 /* Accumulate deltas */ | |
| 112 double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind; | |
| 113 if( ind_tmp > double_step_size_threshold ) { | |
| 114 *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold; | |
| 115 } else { | |
| 116 *prev_ind += ind_tmp; | |
| 117 } | |
| 118 } | |
| 119 *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 ); | |
| 120 | |
| 121 /* Scale and convert to linear scale */ | |
| 122 gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */ | |
| 123 } | |
| 124 } | |
| 125 | |
| 126 /* Compute unique identifier of gain indices vector */ | |
| 127 opus_int32 silk_gains_ID( /* O returns unique identifier of gains */ | |
| 128 const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */ | |
| 129 const opus_int nb_subfr /* I number of subframes */ | |
| 130 ) | |
| 131 { | |
| 132 opus_int k; | |
| 133 opus_int32 gainsID; | |
| 134 | |
| 135 gainsID = 0; | |
| 136 for( k = 0; k < nb_subfr; k++ ) { | |
| 137 gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 ); | |
| 138 } | |
| 139 | |
| 140 return gainsID; | |
| 141 } |
