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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. */
silk_resampler_private_up2_HQ(opus_int32 * S,opus_int16 * out,const opus_int16 * in,opus_int32 len)38 void 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
silk_resampler_private_up2_HQ_wrapper(void * SS,opus_int16 * out,const opus_int16 * in,opus_int32 len)104 void 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