138 lines
6.7 KiB
C
138 lines
6.7 KiB
C
/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#include "opus/opus_config.h"
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#include "opus/silk/main.h"
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#define OFFSET ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 )
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#define SCALE_Q16 ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) )
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#define INV_SCALE_Q16 ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) )
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/* Gain scalar quantization with hysteresis, uniform on log scale */
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void silk_gains_quant(
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opus_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */
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opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */
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opus_int8 *prev_ind, /* I/O last index in previous frame */
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const opus_int conditional, /* I first gain is delta coded if 1 */
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const opus_int nb_subfr /* I number of subframes */
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)
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{
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opus_int k, double_step_size_threshold;
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for( k = 0; k < nb_subfr; k++ ) {
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/* Convert to log scale, scale, floor() */
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ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET );
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/* Round towards previous quantized gain (hysteresis) */
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if( ind[ k ] < *prev_ind ) {
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ind[ k ]++;
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}
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ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
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/* Compute delta indices and limit */
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if( k == 0 && conditional == 0 ) {
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/* Full index */
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ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
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*prev_ind = ind[ k ];
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} else {
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/* Delta index */
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ind[ k ] = ind[ k ] - *prev_ind;
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/* Double the quantization step size for large gain increases, so that the max gain level can be reached */
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double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
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if( ind[ k ] > double_step_size_threshold ) {
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ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
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}
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ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
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/* Accumulate deltas */
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if( ind[ k ] > double_step_size_threshold ) {
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*prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
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} else {
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*prev_ind += ind[ k ];
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}
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/* Shift to make non-negative */
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ind[ k ] -= MIN_DELTA_GAIN_QUANT;
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}
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/* Scale and convert to linear scale */
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gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
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}
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}
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/* Gains scalar dequantization, uniform on log scale */
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void silk_gains_dequant(
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opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */
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const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
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opus_int8 *prev_ind, /* I/O last index in previous frame */
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const opus_int conditional, /* I first gain is delta coded if 1 */
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const opus_int nb_subfr /* I number of subframes */
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)
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{
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opus_int k, ind_tmp, double_step_size_threshold;
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for( k = 0; k < nb_subfr; k++ ) {
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if( k == 0 && conditional == 0 ) {
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/* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */
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*prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 );
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} else {
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/* Delta index */
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ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT;
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/* Accumulate deltas */
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double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
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if( ind_tmp > double_step_size_threshold ) {
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*prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold;
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} else {
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*prev_ind += ind_tmp;
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}
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}
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*prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 );
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/* Scale and convert to linear scale */
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gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
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}
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}
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/* Compute unique identifier of gain indices vector */
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opus_int32 silk_gains_ID( /* O returns unique identifier of gains */
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const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */
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const opus_int nb_subfr /* I number of subframes */
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)
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{
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opus_int k;
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opus_int32 gainsID;
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gainsID = 0;
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for( k = 0; k < nb_subfr; k++ ) {
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gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
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}
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return gainsID;
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}
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