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/* SoX Resampler Library Copyright (c) 2007-13 robs@users.sourceforge.net
* Licence for this file: LGPL v2.1 See LICENCE for details. */
/* 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] * .5f;
CONVOLVE
output[i] = sum;
}
fifo_read(&p->fifo, 2 * num_out, NULL);
}
#undef _
#undef COEFS
#undef CONVOLVE
#undef FUNCTION
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