ref: c43633d1a9d3747f96fc30a32f6fdaa322195aed
dir: /silk/resampler_private_up2_HQ.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "SigProc_FIX.h"
#include "resampler_private.h"
/* Upsample by a factor 2, high quality */
/* Uses 2nd order allpass filters for the 2x upsampling, followed by a */
/* notch filter just above Nyquist. */
void silk_resampler_private_up2_HQ(
opus_int32 *S, /* I/O Resampler state [ 6 ] */
opus_int16 *out, /* O Output signal [ 2 * len ] */
const opus_int16 *in, /* I Input signal [ len ] */
opus_int32 len /* I Number of input samples */
)
{
opus_int32 k;
opus_int32 in32, out32_1, out32_2, Y, X;
silk_assert( silk_resampler_up2_hq_0[ 0 ] > 0 );
silk_assert( silk_resampler_up2_hq_0[ 1 ] > 0 );
silk_assert( silk_resampler_up2_hq_0[ 2 ] < 0 );
silk_assert( silk_resampler_up2_hq_1[ 0 ] > 0 );
silk_assert( silk_resampler_up2_hq_1[ 1 ] > 0 );
silk_assert( silk_resampler_up2_hq_1[ 2 ] < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len; k++ ) {
/* Convert to Q10 */
in32 = silk_LSHIFT( (opus_int32)in[ k ], 10 );
/* First all-pass section for even output sample */
Y = silk_SUB32( in32, S[ 0 ] );
X = silk_SMULWB( Y, silk_resampler_up2_hq_0[ 0 ] );
out32_1 = silk_ADD32( S[ 0 ], X );
S[ 0 ] = silk_ADD32( in32, X );
/* Second all-pass section for even output sample */
Y = silk_SUB32( out32_1, S[ 1 ] );
X = silk_SMULWB( Y, silk_resampler_up2_hq_0[ 1 ] );
out32_2 = silk_ADD32( S[ 1 ], X );
S[ 1 ] = silk_ADD32( out32_1, X );
/* Third all-pass section for even output sample */
Y = silk_SUB32( out32_2, S[ 2 ] );
X = silk_SMLAWB( Y, Y, silk_resampler_up2_hq_0[ 2 ] );
out32_1 = silk_ADD32( S[ 2 ], X );
S[ 2 ] = silk_ADD32( out32_2, X );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32_1, 10 ) );
/* First all-pass section for odd output sample */
Y = silk_SUB32( in32, S[ 3 ] );
X = silk_SMULWB( Y, silk_resampler_up2_hq_1[ 0 ] );
out32_1 = silk_ADD32( S[ 3 ], X );
S[ 3 ] = silk_ADD32( in32, X );
/* Second all-pass section for odd output sample */
Y = silk_SUB32( out32_1, S[ 4 ] );
X = silk_SMULWB( Y, silk_resampler_up2_hq_1[ 1 ] );
out32_2 = silk_ADD32( S[ 4 ], X );
S[ 4 ] = silk_ADD32( out32_1, X );
/* Third all-pass section for odd output sample */
Y = silk_SUB32( out32_2, S[ 5 ] );
X = silk_SMLAWB( Y, Y, silk_resampler_up2_hq_1[ 2 ] );
out32_1 = silk_ADD32( S[ 5 ], X );
S[ 5 ] = silk_ADD32( out32_2, X );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k + 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32_1, 10 ) );
}
}
void silk_resampler_private_up2_HQ_wrapper(
void *SS, /* I/O Resampler state (unused) */
opus_int16 *out, /* O Output signal [ 2 * len ] */
const opus_int16 *in, /* I Input signal [ len ] */
opus_int32 len /* I Number of input samples */
)
{
silk_resampler_state_struct *S = (silk_resampler_state_struct *)SS;
silk_resampler_private_up2_HQ( S->sIIR, out, in, len );
}