16b964020f
git-svn-id: svn://localhost/ardour2/branches/3.0@5424 d708f5d6-7413-0410-9779-e7cbd77b26cf
84 lines
2.0 KiB
C++
84 lines
2.0 KiB
C++
#include <stdint.h>
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#include <cstdio>
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#include "ardour/interpolation.h"
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using namespace ARDOUR;
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nframes_t
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LinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
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{
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// index in the input buffers
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nframes_t i = 0;
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double acceleration;
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double distance = 0.0;
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if (_speed != _target_speed) {
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acceleration = _target_speed - _speed;
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} else {
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acceleration = 0.0;
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}
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distance = phase[channel];
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for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
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i = floor(distance);
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Sample fractional_phase_part = distance - i;
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if (fractional_phase_part >= 1.0) {
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fractional_phase_part -= 1.0;
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i++;
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}
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if (input && output) {
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// Linearly interpolate into the output buffer
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output[outsample] =
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input[i] * (1.0f - fractional_phase_part) +
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input[i+1] * fractional_phase_part;
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}
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distance += _speed + acceleration;
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}
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i = floor(distance);
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phase[channel] = distance - floor(distance);
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return i;
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}
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nframes_t
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CubicInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
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{
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// index in the input buffers
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nframes_t i = 0;
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double acceleration;
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double distance = 0.0;
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if (_speed != _target_speed) {
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acceleration = _target_speed - _speed;
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} else {
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acceleration = 0.0;
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}
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distance = phase[channel];
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for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
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i = floor(distance);
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Sample fractional_phase_part = distance - i;
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if (fractional_phase_part >= 1.0) {
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fractional_phase_part -= 1.0;
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i++;
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}
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if (input && output) {
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// Cubically interpolate into the output buffer
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output[outsample] = cube_interp(fractional_phase_part, input[i-1], input[i], input[i+1], input[i+2]);
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}
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distance += _speed + acceleration;
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}
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i = floor(distance);
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phase[channel] = distance - floor(distance);
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return i;
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}
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