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#include <stdint.h>
#include <cstdio>
#include "ardour/interpolation.h"
using namespace ARDOUR;
nframes_t
LinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
{
// index in the input buffers
nframes_t i = 0;
double acceleration;
double distance = 0.0;
if (_speed != _target_speed) {
acceleration = _target_speed - _speed;
} else {
acceleration = 0.0;
}
distance = phase[channel];
for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
i = floor(distance);
Sample fractional_phase_part = distance - i;
if (fractional_phase_part >= 1.0) {
fractional_phase_part -= 1.0;
i++;
}
if (input && output) {
// Linearly interpolate into the output buffer
output[outsample] =
input[i] * (1.0f - fractional_phase_part) +
input[i+1] * fractional_phase_part;
}
distance += _speed + acceleration;
}
i = floor(distance);
phase[channel] = distance - floor(distance);
return i;
}
nframes_t
CubicInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
{
// index in the input buffers
nframes_t i = 0;
double acceleration;
double distance = 0.0;
if (_speed != _target_speed) {
acceleration = _target_speed - _speed;
} else {
acceleration = 0.0;
}
distance = phase[channel];
for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
i = floor(distance);
Sample fractional_phase_part = distance - i;
if (fractional_phase_part >= 1.0) {
fractional_phase_part -= 1.0;
i++;
}
if (input && output) {
// Cubically interpolate into the output buffer
output[outsample] = cube_interp(fractional_phase_part, input[i-1], input[i], input[i+1], input[i+2]);
}
distance += _speed + acceleration;
}
i = floor(distance);
phase[channel] = distance - floor(distance);
return i;
}
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