ref: 3d6c341867a4dbce6bf90d74b2f943c22d72959c
dir: /silk/NLSF_VQ_weights_laroia.c/
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "define.h"
#include "SigProc_FIX.h"
/*
R. Laroia, N. Phamdo and N. Farvardin, "Robust and Efficient Quantization of Speech LSP
Parameters Using Structured Vector Quantization", Proc. IEEE Int. Conf. Acoust., Speech,
Signal Processing, pp. 641-644, 1991.
*/
/* Laroia low complexity NLSF weights */
void silk_NLSF_VQ_weights_laroia(
opus_int16 *pNLSFW_Q_OUT, /* O Pointer to input vector weights [D] */
const opus_int16 *pNLSF_Q15, /* I Pointer to input vector [D] */
const opus_int D /* I Input vector dimension (even) */
)
{
opus_int k;
opus_int32 tmp1_int, tmp2_int;
silk_assert( D > 0 );
silk_assert( ( D & 1 ) == 0 );
/* First value */
tmp1_int = silk_max_int( pNLSF_Q15[ 0 ], 1 );
tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
tmp2_int = silk_max_int( pNLSF_Q15[ 1 ] - pNLSF_Q15[ 0 ], 1 );
tmp2_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp2_int );
pNLSFW_Q_OUT[ 0 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
silk_assert( pNLSFW_Q_OUT[ 0 ] > 0 );
/* Main loop */
for( k = 1; k < D - 1; k += 2 ) {
tmp1_int = silk_max_int( pNLSF_Q15[ k + 1 ] - pNLSF_Q15[ k ], 1 );
tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
pNLSFW_Q_OUT[ k ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
silk_assert( pNLSFW_Q_OUT[ k ] > 0 );
tmp2_int = silk_max_int( pNLSF_Q15[ k + 2 ] - pNLSF_Q15[ k + 1 ], 1 );
tmp2_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp2_int );
pNLSFW_Q_OUT[ k + 1 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
silk_assert( pNLSFW_Q_OUT[ k + 1 ] > 0 );
}
/* Last value */
tmp1_int = silk_max_int( ( 1 << 15 ) - pNLSF_Q15[ D - 1 ], 1 );
tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
pNLSFW_Q_OUT[ D - 1 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
silk_assert( pNLSFW_Q_OUT[ D - 1 ] > 0 );
}