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142 lines
6.8 KiB
142 lines
6.8 KiB
/*********************************************************************** |
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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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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
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#endif |
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#include "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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*prev_ind = silk_min_int( *prev_ind, N_LEVELS_QGAIN - 1 ); |
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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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