shithub: opus

ref: 64ae0a960b0a702e03616c618872c845b74d6adb
dir: /silk/resampler_private_IIR_FIR.c/

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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "SigProc_FIX.h"
#include "resampler_private.h"

static inline opus_int16 *silk_resampler_private_IIR_FIR_INTERPOL(
    opus_int16  *out, 
    opus_int16  *buf, 
    opus_int32  max_index_Q16, 
    opus_int32  index_increment_Q16 
)
{
    opus_int32 index_Q16, res_Q15;
    opus_int16 *buf_ptr;
    opus_int32 table_index;

    /* Interpolate upsampled signal and store in output array */
    for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
        table_index = silk_SMULWB( index_Q16 & 0xFFFF, 144 );
        buf_ptr = &buf[ index_Q16 >> 16 ];

        res_Q15 = silk_SMULBB(          buf_ptr[ 0 ], silk_resampler_frac_FIR_144[       table_index ][ 0 ] );
        res_Q15 = silk_SMLABB( res_Q15, buf_ptr[ 1 ], silk_resampler_frac_FIR_144[       table_index ][ 1 ] );
        res_Q15 = silk_SMLABB( res_Q15, buf_ptr[ 2 ], silk_resampler_frac_FIR_144[       table_index ][ 2 ] );
        res_Q15 = silk_SMLABB( res_Q15, buf_ptr[ 3 ], silk_resampler_frac_FIR_144[ 143 - table_index ][ 2 ] );
        res_Q15 = silk_SMLABB( res_Q15, buf_ptr[ 4 ], silk_resampler_frac_FIR_144[ 143 - table_index ][ 1 ] );
        res_Q15 = silk_SMLABB( res_Q15, buf_ptr[ 5 ], silk_resampler_frac_FIR_144[ 143 - table_index ][ 0 ] );
        *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q15, 15 ) );
    }
    return out;
}
/* Upsample using a combination of allpass-based 2x upsampling and FIR interpolation */
void silk_resampler_private_IIR_FIR(
    void                            *SS,            /* I/O  Resampler state             */
    opus_int16                      out[],          /* O    Output signal               */
    const opus_int16                in[],           /* I    Input signal                */
    opus_int32                      inLen           /* I    Number of input samples     */
)
{
    silk_resampler_state_struct *S = (silk_resampler_state_struct *)SS;
    opus_int32 nSamplesIn;
    opus_int32 max_index_Q16, index_increment_Q16;
    opus_int16 buf[ 2 * RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_ORDER_FIR_144 ];

    /* Copy buffered samples to start of buffer */
    silk_memcpy( buf, S->sFIR, RESAMPLER_ORDER_FIR_144 * sizeof( opus_int32 ) );

    /* Iterate over blocks of frameSizeIn input samples */
    index_increment_Q16 = S->invRatio_Q16;
    while( 1 ) {
        nSamplesIn = silk_min( inLen, S->batchSize );

        silk_assert( S->input2x );
        /* Upsample 2x */
        silk_resampler_private_up2_HQ( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, nSamplesIn );

        max_index_Q16 = silk_LSHIFT32( nSamplesIn, 16 + S->input2x );         /* +1 if 2x upsampling */
        out = silk_resampler_private_IIR_FIR_INTERPOL(out, buf, max_index_Q16, index_increment_Q16);
        in += nSamplesIn;
        inLen -= nSamplesIn;

        if( inLen > 0 ) {
            /* More iterations to do; copy last part of filtered signal to beginning of buffer */
            silk_memcpy( buf, &buf[ nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( opus_int32 ) );
        } else {
            break;
        }
    }

    /* Copy last part of filtered signal to the state for the next call */
    silk_memcpy( S->sFIR, &buf[nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( opus_int32 ) );
}