#include "filter.h" typedef struct samplerate { double factor; struct { filter_lowpass_t lp; double in_index; } down; struct { filter_lowpass_t lp; double in_index; } up; } samplerate_t; int init_samplerate(samplerate_t *state, double samplerate); int samplerate_downsample(samplerate_t *state, int16_t *input, int input_num, int16_t *output); int samplerate_upsample(samplerate_t *state, int16_t *input, int input_num, int16_t *output);