ref: f7479653be7649267fd9e2096adf47862cea1a95
dir: /src_SigProc_FIX/SKP_Silk_resampler_up2.c/
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/* *
* SKP_Silk_resampler_up2.c *
* *
* Upsample by a factor 2, low quality *
* *
* Copyright 2010 (c), Skype Limited *
* */
#include "SKP_Silk_SigProc_FIX.h"
#include "SKP_Silk_resampler_rom.h"
/* Upsample by a factor 2, low quality */
void SKP_Silk_resampler_up2(
SKP_int32 *S, /* I/O: State vector [ 2 ] */
SKP_int16 *out, /* O: Output signal [ 2 * len ] */
const SKP_int16 *in, /* I: Input signal [ len ] */
SKP_int32 len /* I: Number of input samples */
)
{
SKP_int32 k;
SKP_int32 in32, out32, Y, X;
SKP_assert( SKP_Silk_resampler_up2_lq_0 > 0 );
SKP_assert( SKP_Silk_resampler_up2_lq_1 < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ k ], 10 );
/* All-pass section for even output sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_lq_0 );
out32 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Convert back to int16 and store to output */
out[ 2 * k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 10 ) );
/* All-pass section for odd output sample */
Y = SKP_SUB32( in32, S[ 1 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_lq_1 );
out32 = SKP_ADD32( S[ 1 ], X );
S[ 1 ] = SKP_ADD32( in32, X );
/* Convert back to int16 and store to output */
out[ 2 * k + 1 ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 10 ) );
}
}