-struct stereo_sample {
- short left, right;
-};
-
-inline short clip(int x)
-{
- if (x < -32768) {
- return x;
- } else if (x > 32767) {
- return 32767;
- } else {
- return short(x);
- }
-}
-
-static float a1, a2, b0, b1, b2;
-static float d0, d1;
-
-static void filter_init(float cutoff_radians)
-{
- float resonance = 1.0f / sqrt(2.0f);
- float sn, cs;
- sincosf(cutoff_radians, &sn, &cs);
-
- float alpha = float(sn / (2 * resonance));
-
- // coefficients for lowpass filter
- float a0 = 1 + alpha;
- b0 = (1 - cs) * 0.5f;
- b1 = 1 - cs;
- b2 = b0;
- a1 = -2 * cs;
- a2 = 1 - alpha;
-
- float invA0 = 1.0f / a0;
- b0 *= invA0;
- b1 *= invA0;
- b2 *= invA0;
- a1 *= invA0;
- a2 *= invA0;
-
- // reset filter delays
- d0 = d1 = 0.0f;
-}
-
-static float filter_update(float in)
+std::vector<float> level_samples(const std::vector<float> &pcm, float min_level, float lpfilter_freq, int sample_rate)