-void
-LibSamplerateInterpolation::reset_state ()
-{
- printf("INTERPOLATION: reset_state()\n");
- for (int i = 0; i < state.size(); i++) {
- if (state[i]) {
- src_reset (state[i]);
- } else {
- state[i] = src_new (SRC_SINC_FASTEST, 1, &error);
+ i = lrintf (f);
+
+ /* fractional_phase_part only reaches 1.0 thanks to float imprecision. In theory
+ it should always be < 1.0. If it ever >= 1.0, then bump the index we use
+ and back it off. This is the point where we "skip" an entire sample in the
+ input, because the phase part has accumulated so much error that we should
+ really be closer to the next sample. or something like that ...
+ */
+
+ if (fractional_phase_part >= 1.0) {
+ fractional_phase_part -= 1.0;
+ ++i;
+ }
+
+ // Cubically interpolate into the output buffer: keep this inlined for speed and rely on compiler
+ // optimization to take care of the rest
+ // shamelessly ripped from Steve Harris' swh-plugins (ladspa-util.h)
+
+ output[outsample] = input[i] + 0.5f * fractional_phase_part * (input[i+1] - inm1 +
+ fractional_phase_part * (4.0f * input[i+1] + 2.0f * inm1 - 5.0f * input[i] - input[i+2] +
+ fractional_phase_part * (3.0f * (input[i] - input[i+1]) - inm1 + input[i+2])));
+
+ distance += _speed + acceleration;
+ inm1 = input[i];
+ }
+
+ i = floor(distance);
+ phase[channel] = distance - floor(distance);
+
+ } else {
+ /* used to calculate play-distance with acceleration (silent roll)
+ * (use same algorithm as real playback for identical rounding/floor'ing)
+ */
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ distance += _speed + acceleration;