| /*********************************************************************** |
| Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
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| modification, are permitted provided that the following conditions |
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| this list of conditions and the following disclaimer. |
| - Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| - Neither the name of Internet Society, IETF or IETF Trust, nor the |
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| products derived from this software without specific prior written |
| permission. |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| ***********************************************************************/ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include "main.h" |
| |
| #define OFFSET ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 ) |
| #define SCALE_Q16 ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) |
| #define INV_SCALE_Q16 ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) ) |
| |
| /* Gain scalar quantization with hysteresis, uniform on log scale */ |
| void silk_gains_quant( |
| opus_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */ |
| opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */ |
| opus_int8 *prev_ind, /* I/O last index in previous frame */ |
| const opus_int conditional, /* I first gain is delta coded if 1 */ |
| const opus_int nb_subfr /* I number of subframes */ |
| ) |
| { |
| opus_int k, double_step_size_threshold; |
| |
| for( k = 0; k < nb_subfr; k++ ) { |
| /* Convert to log scale, scale, floor() */ |
| ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET ); |
| |
| /* Round towards previous quantized gain (hysteresis) */ |
| if( ind[ k ] < *prev_ind ) { |
| ind[ k ]++; |
| } |
| ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 ); |
| |
| /* Compute delta indices and limit */ |
| if( k == 0 && conditional == 0 ) { |
| /* Full index */ |
| ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 ); |
| *prev_ind = ind[ k ]; |
| } else { |
| /* Delta index */ |
| ind[ k ] = ind[ k ] - *prev_ind; |
| |
| /* Double the quantization step size for large gain increases, so that the max gain level can be reached */ |
| double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind; |
| if( ind[ k ] > double_step_size_threshold ) { |
| ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 ); |
| } |
| |
| ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT ); |
| |
| /* Accumulate deltas */ |
| if( ind[ k ] > double_step_size_threshold ) { |
| *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold; |
| *prev_ind = silk_min_int( *prev_ind, N_LEVELS_QGAIN - 1 ); |
| } else { |
| *prev_ind += ind[ k ]; |
| } |
| |
| /* Shift to make non-negative */ |
| ind[ k ] -= MIN_DELTA_GAIN_QUANT; |
| } |
| |
| /* Scale and convert to linear scale */ |
| gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */ |
| } |
| } |
| |
| /* Gains scalar dequantization, uniform on log scale */ |
| void silk_gains_dequant( |
| opus_int32 gain_Q16[ MAX_NB_SUBFR ], /* O quantized gains */ |
| const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */ |
| opus_int8 *prev_ind, /* I/O last index in previous frame */ |
| const opus_int conditional, /* I first gain is delta coded if 1 */ |
| const opus_int nb_subfr /* I number of subframes */ |
| ) |
| { |
| opus_int k, ind_tmp, double_step_size_threshold; |
| |
| for( k = 0; k < nb_subfr; k++ ) { |
| if( k == 0 && conditional == 0 ) { |
| /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */ |
| *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 ); |
| } else { |
| /* Delta index */ |
| ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT; |
| |
| /* Accumulate deltas */ |
| double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind; |
| if( ind_tmp > double_step_size_threshold ) { |
| *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold; |
| } else { |
| *prev_ind += ind_tmp; |
| } |
| } |
| *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 ); |
| |
| /* Scale and convert to linear scale */ |
| gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */ |
| } |
| } |
| |
| /* Compute unique identifier of gain indices vector */ |
| opus_int32 silk_gains_ID( /* O returns unique identifier of gains */ |
| const opus_int8 ind[ MAX_NB_SUBFR ], /* I gain indices */ |
| const opus_int nb_subfr /* I number of subframes */ |
| ) |
| { |
| opus_int k; |
| opus_int32 gainsID; |
| |
| gainsID = 0; |
| for( k = 0; k < nb_subfr; k++ ) { |
| gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 ); |
| } |
| |
| return gainsID; |
| } |
