/*
- Copyright (C) 2012 Paul Davis
+ Copyright (C) 2012 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <cstdio>
#include "ardour/interpolation.h"
+#include "ardour/midi_buffer.h"
using namespace ARDOUR;
}
if (input && output) {
- // Linearly interpolate into the output buffer
+ // Linearly interpolate into the output buffer
output[outsample] =
input[i] * (1.0f - fractional_phase_part) +
input[i+1] * fractional_phase_part;
framecnt_t
CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output)
{
- // index in the input buffers
- framecnt_t i = 0;
+ // index in the input buffers
+ framecnt_t i = 0;
+
+ double acceleration;
+ double distance = 0.0;
- double acceleration;
- double distance = 0.0;
+ if (_speed != _target_speed) {
+ acceleration = _target_speed - _speed;
+ } else {
+ acceleration = 0.0;
+ }
- if (_speed != _target_speed) {
- acceleration = _target_speed - _speed;
- } else {
- acceleration = 0.0;
- }
+ distance = phase[channel];
- distance = phase[channel];
+ if (nframes < 3) {
+ /* no interpolation possible */
- if (nframes < 3) {
- /* no interpolation possible */
+ if (input && output) {
+ for (i = 0; i < nframes; ++i) {
+ output[i] = input[i];
+ }
+ }
+
+ return nframes;
+ }
- for (i = 0; i < nframes; ++i) {
- output[i] = input[i];
- }
+ /* keep this condition out of the inner loop */
- return nframes;
- }
+ if (input && output) {
- /* keep this condition out of the inner loop */
+ Sample inm1;
- if (input && output) {
+ if (floor (distance) == 0.0) {
+ /* best guess for the fake point we have to add to be able to interpolate at i == 0:
+ .... maintain slope of first actual segment ...
+ */
+ inm1 = input[i] - (input[i+1] - input[i]);
+ } else {
+ inm1 = input[i-1];
+ }
- Sample inm1;
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
- if (floor (distance) == 0.0) {
- /* best guess for the fake point we have to add to be able to interpolate at i == 0:
- .... maintain slope of first actual segment ...
- */
- inm1 = input[i] - (input[i+1] - input[i]);
- } else {
- inm1 = input[i-1];
- }
+ float f = floor (distance);
+ float fractional_phase_part = distance - f;
- for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ /* get the index into the input we should start with */
- float f = floor (distance);
- float fractional_phase_part = distance - f;
+ i = lrintf (f);
- /* get the index into the input we should start with */
+ /* 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 ...
+ */
- i = lrintf (f);
+ if (fractional_phase_part >= 1.0) {
+ fractional_phase_part -= 1.0;
+ ++i;
+ }
- /* 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 ...
- */
+ // 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)
- if (fractional_phase_part >= 1.0) {
- fractional_phase_part -= 1.0;
- ++i;
- }
+ 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])));
- // 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)
+ distance += _speed + acceleration;
+ inm1 = input[i];
+ }
- 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])));
+ i = floor(distance);
+ phase[channel] = distance - floor(distance);
- distance += _speed + acceleration;
- inm1 = input[i];
- }
+ } 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;
+ }
+ i = floor(distance);
+ }
- i = floor(distance);
- phase[channel] = distance - floor(distance);
+ return i;
+}
- } 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;
- }
- i = floor(distance);
- }
+framecnt_t
+CubicMidiInterpolation::distance (framecnt_t nframes, bool roll)
+{
+ assert(phase.size() == 1);
- return i;
+ framecnt_t i = 0;
+
+ double acceleration;
+ double distance = 0.0;
+
+ if (nframes < 3) {
+ return nframes;
+ }
+
+ if (_speed != _target_speed) {
+ acceleration = _target_speed - _speed;
+ } else {
+ acceleration = 0.0;
+ }
+
+ distance = phase[0];
+
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ distance += _speed + acceleration;
+ }
+
+ if (roll) {
+ phase[0] = distance - floor(distance);
+ }
+
+ i = floor(distance);
+
+ return i;
}