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/* * | |
* SKP_Silk_resampler_private_up2_HQ.c * | |
* * | |
* Upsample by a factor 2, high quality * | |
* * | |
* Copyright 2010 (c), Skype Limited * | |
* */ | |
#include "SKP_Silk_SigProc_FIX.h" | |
#include "SKP_Silk_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. */ | |
#if (EMBEDDED_ARM<5) && (!defined(__mips__)) | |
void SKP_Silk_resampler_private_up2_HQ( | |
SKP_int32 *S, /* I/O: Resampler state [ 6 ] */ | |
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_1, out32_2, Y, X; | |
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 0 ] > 0 ); | |
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 1 ] < 0 ); | |
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 0 ] > 0 ); | |
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 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 ); | |
/* First all-pass section for even output sample */ | |
Y = SKP_SUB32( in32, S[ 0 ] ); | |
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_0[ 0 ] ); | |
out32_1 = SKP_ADD32( S[ 0 ], X ); | |
S[ 0 ] = SKP_ADD32( in32, X ); | |
/* Second all-pass section for even output sample */ | |
Y = SKP_SUB32( out32_1, S[ 1 ] ); | |
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_0[ 1 ] ); | |
out32_2 = SKP_ADD32( S[ 1 ], X ); | |
S[ 1 ] = SKP_ADD32( out32_1, X ); | |
/* Biquad notch filter */ | |
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] ); | |
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] ); | |
out32_1 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] ); | |
S[ 5 ] = SKP_SUB32( out32_2, S[ 5 ] ); | |
/* Apply gain in Q15, convert back to int16 and store to output */ | |
out[ 2 * k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32( | |
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) ); | |
/* First all-pass section for odd output sample */ | |
Y = SKP_SUB32( in32, S[ 2 ] ); | |
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_1[ 0 ] ); | |
out32_1 = SKP_ADD32( S[ 2 ], X ); | |
S[ 2 ] = SKP_ADD32( in32, X ); | |
/* Second all-pass section for odd output sample */ | |
Y = SKP_SUB32( out32_1, S[ 3 ] ); | |
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_1[ 1 ] ); | |
out32_2 = SKP_ADD32( S[ 3 ], X ); | |
S[ 3 ] = SKP_ADD32( out32_1, X ); | |
/* Biquad notch filter */ | |
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] ); | |
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] ); | |
out32_1 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] ); | |
S[ 4 ] = SKP_SUB32( out32_2, S[ 4 ] ); | |
/* Apply gain in Q15, convert back to int16 and store to output */ | |
out[ 2 * k + 1 ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32( | |
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) ); | |
} | |
} | |
#endif | |
void SKP_Silk_resampler_private_up2_HQ_wrapper( | |
void *SS, /* I/O: Resampler state (unused) */ | |
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_Silk_resampler_state_struct *S = (SKP_Silk_resampler_state_struct *)SS; | |
SKP_Silk_resampler_private_up2_HQ( S->sIIR, out, in, len ); | |
} |