1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/gain_quant.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,141 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "main.h"
1.36 +
1.37 +#define OFFSET ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 )
1.38 +#define SCALE_Q16 ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) )
1.39 +#define INV_SCALE_Q16 ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) )
1.40 +
1.41 +/* Gain scalar quantization with hysteresis, uniform on log scale */
1.42 +void silk_gains_quant(
1.43 + opus_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */
1.44 + opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */
1.45 + opus_int8 *prev_ind, /* I/O last index in previous frame */
1.46 + const opus_int conditional, /* I first gain is delta coded if 1 */
1.47 + const opus_int nb_subfr /* I number of subframes */
1.48 +)
1.49 +{
1.50 + opus_int k, double_step_size_threshold;
1.51 +
1.52 + for( k = 0; k < nb_subfr; k++ ) {
1.53 + /* Convert to log scale, scale, floor() */
1.54 + ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET );
1.55 +
1.56 + /* Round towards previous quantized gain (hysteresis) */
1.57 + if( ind[ k ] < *prev_ind ) {
1.58 + ind[ k ]++;
1.59 + }
1.60 + ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
1.61 +
1.62 + /* Compute delta indices and limit */
1.63 + if( k == 0 && conditional == 0 ) {
1.64 + /* Full index */
1.65 + ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
1.66 + *prev_ind = ind[ k ];
1.67 + } else {
1.68 + /* Delta index */
1.69 + ind[ k ] = ind[ k ] - *prev_ind;
1.70 +
1.71 + /* Double the quantization step size for large gain increases, so that the max gain level can be reached */
1.72 + double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
1.73 + if( ind[ k ] > double_step_size_threshold ) {
1.74 + ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
1.75 + }
1.76 +
1.77 + ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
1.78 +
1.79 + /* Accumulate deltas */
1.80 + if( ind[ k ] > double_step_size_threshold ) {
1.81 + *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
1.82 + } else {
1.83 + *prev_ind += ind[ k ];
1.84 + }
1.85 +
1.86 + /* Shift to make non-negative */
1.87 + ind[ k ] -= MIN_DELTA_GAIN_QUANT;
1.88 + }
1.89 +
1.90 + /* Scale and convert to linear scale */
1.91 + gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
1.92 + }
1.93 +}
1.94 +
1.95 +/* Gains scalar dequantization, uniform on log scale */
1.96 +void silk_gains_dequant(
1.97 + opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */
1.98 + const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
1.99 + opus_int8 *prev_ind, /* I/O last index in previous frame */
1.100 + const opus_int conditional, /* I first gain is delta coded if 1 */
1.101 + const opus_int nb_subfr /* I number of subframes */
1.102 +)
1.103 +{
1.104 + opus_int k, ind_tmp, double_step_size_threshold;
1.105 +
1.106 + for( k = 0; k < nb_subfr; k++ ) {
1.107 + if( k == 0 && conditional == 0 ) {
1.108 + /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */
1.109 + *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 );
1.110 + } else {
1.111 + /* Delta index */
1.112 + ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT;
1.113 +
1.114 + /* Accumulate deltas */
1.115 + double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
1.116 + if( ind_tmp > double_step_size_threshold ) {
1.117 + *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold;
1.118 + } else {
1.119 + *prev_ind += ind_tmp;
1.120 + }
1.121 + }
1.122 + *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 );
1.123 +
1.124 + /* Scale and convert to linear scale */
1.125 + gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
1.126 + }
1.127 +}
1.128 +
1.129 +/* Compute unique identifier of gain indices vector */
1.130 +opus_int32 silk_gains_ID( /* O returns unique identifier of gains */
1.131 + const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
1.132 + const opus_int nb_subfr /* I number of subframes */
1.133 +)
1.134 +{
1.135 + opus_int k;
1.136 + opus_int32 gainsID;
1.137 +
1.138 + gainsID = 0;
1.139 + for( k = 0; k < nb_subfr; k++ ) {
1.140 + gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
1.141 + }
1.142 +
1.143 + return gainsID;
1.144 +}
