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media/libopus/silk/gain_quant.c@b8a032363ba2 (annotated)

media/libopus/silk/gain_quant.c

Thu, 22 Jan 2015 13:21:57 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Thu, 22 Jan 2015 13:21:57 +0100
branch
TOR_BUG_9701
changeset 15
b8a032363ba2
permissions
-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

michael@0 1 /***********************************************************************
michael@0 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0 3 Redistribution and use in source and binary forms, with or without
michael@0 4 modification, are permitted provided that the following conditions
michael@0 5 are met:
michael@0 6 - Redistributions of source code must retain the above copyright notice,
michael@0 7 this list of conditions and the following disclaimer.
michael@0 8 - Redistributions in binary form must reproduce the above copyright
michael@0 9 notice, this list of conditions and the following disclaimer in the
michael@0 10 documentation and/or other materials provided with the distribution.
michael@0 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0 12 names of specific contributors, may be used to endorse or promote
michael@0 13 products derived from this software without specific prior written
michael@0 14 permission.
michael@0 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0 25 POSSIBILITY OF SUCH DAMAGE.
michael@0 26 ***********************************************************************/
michael@0 27
michael@0 28 #ifdef HAVE_CONFIG_H
michael@0 29 #include "config.h"
michael@0 30 #endif
michael@0 31
michael@0 32 #include "main.h"
michael@0 33
michael@0 34 #define OFFSET ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 )
michael@0 35 #define SCALE_Q16 ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) )
michael@0 36 #define INV_SCALE_Q16 ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) )
michael@0 37
michael@0 38 /* Gain scalar quantization with hysteresis, uniform on log scale */
michael@0 39 void silk_gains_quant(
michael@0 40 opus_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */
michael@0 41 opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */
michael@0 42 opus_int8 *prev_ind, /* I/O last index in previous frame */
michael@0 43 const opus_int conditional, /* I first gain is delta coded if 1 */
michael@0 44 const opus_int nb_subfr /* I number of subframes */
michael@0 45 )
michael@0 46 {
michael@0 47 opus_int k, double_step_size_threshold;
michael@0 48
michael@0 49 for( k = 0; k < nb_subfr; k++ ) {
michael@0 50 /* Convert to log scale, scale, floor() */
michael@0 51 ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET );
michael@0 52
michael@0 53 /* Round towards previous quantized gain (hysteresis) */
michael@0 54 if( ind[ k ] < *prev_ind ) {
michael@0 55 ind[ k ]++;
michael@0 56 }
michael@0 57 ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
michael@0 58
michael@0 59 /* Compute delta indices and limit */
michael@0 60 if( k == 0 && conditional == 0 ) {
michael@0 61 /* Full index */
michael@0 62 ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
michael@0 63 *prev_ind = ind[ k ];
michael@0 64 } else {
michael@0 65 /* Delta index */
michael@0 66 ind[ k ] = ind[ k ] - *prev_ind;
michael@0 67
michael@0 68 /* Double the quantization step size for large gain increases, so that the max gain level can be reached */
michael@0 69 double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
michael@0 70 if( ind[ k ] > double_step_size_threshold ) {
michael@0 71 ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
michael@0 72 }
michael@0 73
michael@0 74 ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
michael@0 75
michael@0 76 /* Accumulate deltas */
michael@0 77 if( ind[ k ] > double_step_size_threshold ) {
michael@0 78 *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
michael@0 79 } else {
michael@0 80 *prev_ind += ind[ k ];
michael@0 81 }
michael@0 82
michael@0 83 /* Shift to make non-negative */
michael@0 84 ind[ k ] -= MIN_DELTA_GAIN_QUANT;
michael@0 85 }
michael@0 86
michael@0 87 /* Scale and convert to linear scale */
michael@0 88 gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
michael@0 89 }
michael@0 90 }
michael@0 91
michael@0 92 /* Gains scalar dequantization, uniform on log scale */
michael@0 93 void silk_gains_dequant(
michael@0 94 opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */
michael@0 95 const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
michael@0 96 opus_int8 *prev_ind, /* I/O last index in previous frame */
michael@0 97 const opus_int conditional, /* I first gain is delta coded if 1 */
michael@0 98 const opus_int nb_subfr /* I number of subframes */
michael@0 99 )
michael@0 100 {
michael@0 101 opus_int k, ind_tmp, double_step_size_threshold;
michael@0 102
michael@0 103 for( k = 0; k < nb_subfr; k++ ) {
michael@0 104 if( k == 0 && conditional == 0 ) {
michael@0 105 /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */
michael@0 106 *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 );
michael@0 107 } else {
michael@0 108 /* Delta index */
michael@0 109 ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT;
michael@0 110
michael@0 111 /* Accumulate deltas */
michael@0 112 double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
michael@0 113 if( ind_tmp > double_step_size_threshold ) {
michael@0 114 *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold;
michael@0 115 } else {
michael@0 116 *prev_ind += ind_tmp;
michael@0 117 }
michael@0 118 }
michael@0 119 *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 );
michael@0 120
michael@0 121 /* Scale and convert to linear scale */
michael@0 122 gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
michael@0 123 }
michael@0 124 }
michael@0 125
michael@0 126 /* Compute unique identifier of gain indices vector */
michael@0 127 opus_int32 silk_gains_ID( /* O returns unique identifier of gains */
michael@0 128 const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
michael@0 129 const opus_int nb_subfr /* I number of subframes */
michael@0 130 )
michael@0 131 {
michael@0 132 opus_int k;
michael@0 133 opus_int32 gainsID;
michael@0 134
michael@0 135 gainsID = 0;
michael@0 136 for( k = 0; k < nb_subfr; k++ ) {
michael@0 137 gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
michael@0 138 }
michael@0 139
michael@0 140 return gainsID;
michael@0 141 }

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