95 lines
4.8 KiB
C
95 lines
4.8 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, (subject to the limitations in the disclaimer below)
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are permitted provided that the following conditions 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 Skype Limited, nor the names of specific
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contributors, may be used to endorse or promote products derived from
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this software without specific prior written permission.
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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#include "SKP_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 SKP_Silk_gains_quant(
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SKP_int ind[ NB_SUBFR ], /* O gain indices */
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SKP_int32 gain_Q16[ NB_SUBFR ], /* I/O gains (quantized out) */
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SKP_int *prev_ind, /* I/O last index in previous frame */
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const SKP_int conditional /* I first gain is delta coded if 1 */
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)
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{
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SKP_int k;
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for( k = 0; k < NB_SUBFR; k++ ) {
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/* Add half of previous quantization error, convert to log scale, scale, floor() */
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ind[ k ] = SKP_SMULWB( SCALE_Q16, SKP_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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/* 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 ] = SKP_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
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ind[ k ] = SKP_max_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT );
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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 ] = SKP_LIMIT_int( ind[ k ] - *prev_ind, MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
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/* Accumulate deltas */
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*prev_ind += ind[ k ];
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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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/* Convert to linear scale and scale */
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gain_Q16[ k ] = SKP_Silk_log2lin( SKP_min_32( SKP_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 SKP_Silk_gains_dequant(
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SKP_int32 gain_Q16[ NB_SUBFR ], /* O quantized gains */
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const SKP_int ind[ NB_SUBFR ], /* I gain indices */
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SKP_int *prev_ind, /* I/O last index in previous frame */
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const SKP_int conditional /* I first gain is delta coded if 1 */
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)
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{
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SKP_int k;
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for( k = 0; k < NB_SUBFR; k++ ) {
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if( k == 0 && conditional == 0 ) {
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*prev_ind = ind[ k ];
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} else {
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/* Delta index */
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*prev_ind += ind[ k ] + MIN_DELTA_GAIN_QUANT;
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}
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/* Convert to linear scale and scale */
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gain_Q16[ k ] = SKP_Silk_log2lin( SKP_min_32( SKP_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
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}
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}
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