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15THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "define.h"
33#include "SigProc_FIX.h"
34
35/*
36R. Laroia, N. Phamdo and N. Farvardin, "Robust and Efficient Quantization of Speech LSP
37Parameters Using Structured Vector Quantization", Proc. IEEE Int. Conf. Acoust., Speech,
38Signal Processing, pp. 641-644, 1991.
39*/
40
41/* Laroia low complexity NLSF weights */
42void silk_NLSF_VQ_weights_laroia(
43    opus_int16                  *pNLSFW_Q_OUT,      /* O     Pointer to input vector weights [D]                        */
44    const opus_int16            *pNLSF_Q15,         /* I     Pointer to input vector         [D]                        */
45    const opus_int              D                   /* I     Input vector dimension (even)                              */
46)
47{
48    opus_int   k;
49    opus_int32 tmp1_int, tmp2_int;
50
51    silk_assert( D > 0 );
52    silk_assert( ( D & 1 ) == 0 );
53
54    /* First value */
55    tmp1_int = silk_max_int( pNLSF_Q15[ 0 ], 1 );
56    tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
57    tmp2_int = silk_max_int( pNLSF_Q15[ 1 ] - pNLSF_Q15[ 0 ], 1 );
58    tmp2_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp2_int );
59    pNLSFW_Q_OUT[ 0 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
60    silk_assert( pNLSFW_Q_OUT[ 0 ] > 0 );
61
62    /* Main loop */
63    for( k = 1; k < D - 1; k += 2 ) {
64        tmp1_int = silk_max_int( pNLSF_Q15[ k + 1 ] - pNLSF_Q15[ k ], 1 );
65        tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
66        pNLSFW_Q_OUT[ k ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
67        silk_assert( pNLSFW_Q_OUT[ k ] > 0 );
68
69        tmp2_int = silk_max_int( pNLSF_Q15[ k + 2 ] - pNLSF_Q15[ k + 1 ], 1 );
70        tmp2_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp2_int );
71        pNLSFW_Q_OUT[ k + 1 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
72        silk_assert( pNLSFW_Q_OUT[ k + 1 ] > 0 );
73    }
74
75    /* Last value */
76    tmp1_int = silk_max_int( ( 1 << 15 ) - pNLSF_Q15[ D - 1 ], 1 );
77    tmp1_int = silk_DIV32_16( (opus_int32)1 << ( 15 + NLSF_W_Q ), tmp1_int );
78    pNLSFW_Q_OUT[ D - 1 ] = (opus_int16)silk_min_int( tmp1_int + tmp2_int, silk_int16_MAX );
79    silk_assert( pNLSFW_Q_OUT[ D - 1 ] > 0 );
80}
81