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26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "SigProc_FIX.h"
33#include "resampler_private.h"
34
35/* Upsample by a factor 2, high quality */
36/* Uses 2nd order allpass filters for the 2x upsampling, followed by a      */
37/* notch filter just above Nyquist.                                         */
38void silk_resampler_private_up2_HQ(
39    opus_int32                      *S,             /* I/O  Resampler state [ 6 ]       */
40    opus_int16                      *out,           /* O    Output signal [ 2 * len ]   */
41    const opus_int16                *in,            /* I    Input signal [ len ]        */
42    opus_int32                      len             /* I    Number of input samples     */
43)
44{
45    opus_int32 k;
46    opus_int32 in32, out32_1, out32_2, Y, X;
47
48    silk_assert( silk_resampler_up2_hq_0[ 0 ] > 0 );
49    silk_assert( silk_resampler_up2_hq_0[ 1 ] > 0 );
50    silk_assert( silk_resampler_up2_hq_0[ 2 ] < 0 );
51    silk_assert( silk_resampler_up2_hq_1[ 0 ] > 0 );
52    silk_assert( silk_resampler_up2_hq_1[ 1 ] > 0 );
53    silk_assert( silk_resampler_up2_hq_1[ 2 ] < 0 );
54
55    /* Internal variables and state are in Q10 format */
56    for( k = 0; k < len; k++ ) {
57        /* Convert to Q10 */
58        in32 = silk_LSHIFT( (opus_int32)in[ k ], 10 );
59
60        /* First all-pass section for even output sample */
61        Y       = silk_SUB32( in32, S[ 0 ] );
62        X       = silk_SMULWB( Y, silk_resampler_up2_hq_0[ 0 ] );
63        out32_1 = silk_ADD32( S[ 0 ], X );
64        S[ 0 ]  = silk_ADD32( in32, X );
65
66        /* Second all-pass section for even output sample */
67        Y       = silk_SUB32( out32_1, S[ 1 ] );
68        X       = silk_SMULWB( Y, silk_resampler_up2_hq_0[ 1 ] );
69        out32_2 = silk_ADD32( S[ 1 ], X );
70        S[ 1 ]  = silk_ADD32( out32_1, X );
71
72        /* Third all-pass section for even output sample */
73        Y       = silk_SUB32( out32_2, S[ 2 ] );
74        X       = silk_SMLAWB( Y, Y, silk_resampler_up2_hq_0[ 2 ] );
75        out32_1 = silk_ADD32( S[ 2 ], X );
76        S[ 2 ]  = silk_ADD32( out32_2, X );
77
78        /* Apply gain in Q15, convert back to int16 and store to output */
79        out[ 2 * k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32_1, 10 ) );
80
81        /* First all-pass section for odd output sample */
82        Y       = silk_SUB32( in32, S[ 3 ] );
83        X       = silk_SMULWB( Y, silk_resampler_up2_hq_1[ 0 ] );
84        out32_1 = silk_ADD32( S[ 3 ], X );
85        S[ 3 ]  = silk_ADD32( in32, X );
86
87        /* Second all-pass section for odd output sample */
88        Y       = silk_SUB32( out32_1, S[ 4 ] );
89        X       = silk_SMULWB( Y, silk_resampler_up2_hq_1[ 1 ] );
90        out32_2 = silk_ADD32( S[ 4 ], X );
91        S[ 4 ]  = silk_ADD32( out32_1, X );
92
93        /* Third all-pass section for odd output sample */
94        Y       = silk_SUB32( out32_2, S[ 5 ] );
95        X       = silk_SMLAWB( Y, Y, silk_resampler_up2_hq_1[ 2 ] );
96        out32_1 = silk_ADD32( S[ 5 ], X );
97        S[ 5 ]  = silk_ADD32( out32_2, X );
98
99        /* Apply gain in Q15, convert back to int16 and store to output */
100        out[ 2 * k + 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32_1, 10 ) );
101    }
102}
103
104void silk_resampler_private_up2_HQ_wrapper(
105    void                            *SS,            /* I/O  Resampler state (unused)    */
106    opus_int16                      *out,           /* O    Output signal [ 2 * len ]   */
107    const opus_int16                *in,            /* I    Input signal [ len ]        */
108    opus_int32                      len             /* I    Number of input samples     */
109)
110{
111    silk_resampler_state_struct *S = (silk_resampler_state_struct *)SS;
112    silk_resampler_private_up2_HQ( S->sIIR, out, in, len );
113}
114