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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 ) ); | |
} | |
} |