/* Effect: change sample rate  Copyright (c) 2008,12 robs@users.sourceforge.net * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at * your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA */ /* Down-sample by a factor of 2 using a FIR with odd length (LEN).*//* Input must be preceded and followed by LEN >> 1 samples. */ #define _ sum += (input[-(2*j +1)] + input[(2*j +1)]) * COEFS[j], ++j;static void FUNCTION(stage_t * p, fifo_t * output_fifo){  sample_t const * input = stage_read_p(p);  int i, num_out = (stage_occupancy(p) + 1) / 2;  sample_t * output = fifo_reserve(output_fifo, num_out);   for (i = 0; i < num_out; ++i, input += 2) {    int j = 0;    sample_t sum = input[0] * .5;    CONVOLVE    USED(j);    output[i] = sum;  }  fifo_read(&p->fifo, 2 * num_out, NULL);}#undef _#undef COEFS#undef CONVOLVE#undef FUNCTION