+/*
+ 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
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
#include <stdint.h>
#include <cstdio>
#include "ardour/interpolation.h"
+#include "ardour/midi_buffer.h"
using namespace ARDOUR;
-nframes_t
-FixedPointLinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+
+samplecnt_t
+LinearInterpolation::interpolate (int channel, samplecnt_t nframes, Sample *input, Sample *output)
{
- // the idea behind phase is that when the speed is not 1.0, we have to
- // interpolate between samples and then we have to store where we thought we were.
- // rather than being at sample N or N+1, we were at N+0.8792922
- // so the "phase" element, if you want to think about this way,
- // varies from 0 to 1, representing the "offset" between samples
- uint64_t the_phase = last_phase[channel];
-
- // acceleration
- int64_t phi_delta;
-
- // phi = fixed point speed
- if (phi != target_phi) {
- phi_delta = ((int64_t)(target_phi - phi)) / nframes;
- } else {
- phi_delta = 0;
- }
-
// index in the input buffers
- nframes_t i = 0;
+ samplecnt_t i = 0;
+
+ double acceleration = 0;
+
+ if (_speed != _target_speed) {
+ acceleration = _target_speed - _speed;
+ }
+
+ for (samplecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ double const d = phase[channel] + outsample * (_speed + acceleration);
+ i = floor(d);
+ Sample fractional_phase_part = d - i;
+ if (fractional_phase_part >= 1.0) {
+ fractional_phase_part -= 1.0;
+ i++;
+ }
- for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
- i = the_phase >> 24;
- Sample fractional_phase_part = (the_phase & fractional_part_mask) / binary_scaling_factor;
-
if (input && output) {
// Linearly interpolate into the output buffer
- output[outsample] =
+ output[outsample] =
input[i] * (1.0f - fractional_phase_part) +
input[i+1] * fractional_phase_part;
}
-
- the_phase += phi + phi_delta;
}
- last_phase[channel] = (the_phase & fractional_part_mask);
-
- // playback distance
+ double const distance = phase[channel] + nframes * (_speed + acceleration);
+ i = floor(distance);
+ phase[channel] = distance - i;
return i;
}
-void
-FixedPointLinearInterpolation::add_channel_to (int /*input_buffer_size*/, int /*output_buffer_size*/)
-{
- last_phase.push_back (0);
-}
-
-void
-FixedPointLinearInterpolation::remove_channel_from ()
-{
- last_phase.pop_back ();
-}
-
-void
-FixedPointLinearInterpolation::reset()
-{
- for (size_t i = 0; i <= last_phase.size(); i++) {
- last_phase[i] = 0;
- }
-}
-
-
-nframes_t
-LinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+samplecnt_t
+CubicInterpolation::interpolate (int channel, samplecnt_t nframes, Sample *input, Sample *output)
{
// index in the input buffers
- nframes_t i = 0;
-
+ samplecnt_t i = 0;
+
double acceleration;
- double distance = 0.0;
-
+ double distance = phase[channel];
+
if (_speed != _target_speed) {
acceleration = _target_speed - _speed;
} else {
acceleration = 0.0;
}
-
- distance = phase[channel];
- //printf("processing channel: %d\n", channel);
- //printf("phase before: %lf\n", 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++;
- }
- //printf("I: %u, distance: %lf, fractional_phase_part: %lf\n", i, distance, fractional_phase_part);
-
+
+ if (nframes < 3) {
+ /* no interpolation possible */
+
if (input && output) {
- // Linearly interpolate into the output buffer
- output[outsample] =
- input[i] * (1.0f - fractional_phase_part) +
- input[i+1] * fractional_phase_part;
+ for (i = 0; i < nframes; ++i) {
+ output[i] = input[i];
+ }
}
- //printf("distance before: %lf\n", distance);
- distance += _speed + acceleration;
- //printf("distance after: %lf, _speed: %lf\n", distance, _speed);
+
+ phase[channel] = 0;
+ return nframes;
}
-
- //printf("before assignment: i: %d, distance: %lf\n", i, distance);
- i = floor(distance);
- //printf("after assignment: i: %d, distance: %16lf\n", i, distance);
- phase[channel] = distance - floor(distance);
- //printf("speed: %16lf, i after: %d, distance after: %16lf, phase after: %16lf\n", _speed, i, distance, phase[channel]);
-
- return i;
-}
-SplineInterpolation::SplineInterpolation()
-{
- // precompute LU-factorization of matrix A
- // see "Teubner Taschenbuch der Mathematik", p. 1105
- // We only need to calculate up to 20, because they
- // won't change any more above that
- _m[0] = 4.0;
- for (int i = 0; i <= 20 - 2; i++) {
- _l[i] = 1.0 / _m[i];
- _m[i+1] = 4.0 - _l[i];
- }
-}
+ /* keep this condition out of the inner loop */
-nframes_t
-SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
-{
- // How many input samples we need
- nframes_t n = ceil (double(nframes) * _speed + phase[channel]) + 1;
- //printf("n = %d\n", n);
-
- if (n <= 3) {
- return 0;
- }
-
- double M[n], t[n-2];
-
- // natural spline: boundary conditions
- M[0] = 0.0;
- M[n - 1] = 0.0;
-
- // solve L * t = d
- t[0] = 6.0 * (input[0] - 2*input[1] + input[2]);
- for (nframes_t i = 1; i <= n - 3; i++) {
- t[i] = 6.0 * (input[i] - 2*input[i+1] + input[i+2])
- - l(i-1) * t[i-1];
- }
-
- // solve U * M = t
- M[n-2] = t[n-3] / m(n-3);
- for (nframes_t i = n-4;; i--) {
- M[i+1] = (t[i]-M[i+2])/m(i);
- if ( i == 0 ) break;
- }
- assert (M[0] == 0.0 && M[n-1] == 0.0);
-
- // now interpolate
- // 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 x = double(distance) - double(i);
-
- // if distance is something like 0.999999999999
- // it will get rounded to 1 in the conversion to float above
- if (x >= 1.0) {
- x = 0.0;
- i++;
- }
-
- assert(x >= 0.0 && x < 1.0);
-
- if (input && output) {
- assert (i <= n-1);
- double a3 = (M[i+1] - M[i]) / 6.0;
- double a2 = M[i] / 2.0;
- double a1 = input[i+1] - input[i] - (M[i+1] + 2.0*M[i])/6.0;
- double a0 = input[i];
- // interpolate into the output buffer
- output[outsample] = ((a3*x + a2)*x + a1)*x + a0;
- }
- distance += _speed + acceleration;
- }
-
- i = floor(distance);
- phase[channel] = distance - floor(distance);
- assert (phase[channel] >= 0.0 && phase[channel] < 1.0);
-
- return i;
-}
+ if (input && output) {
+ /* best guess for the fake point we have to add to be able to interpolate at i == 0:
+ * .... maintain slope of first actual segment ...
+ */
+ Sample inm1 = input[i] - (input[i+1] - input[i]);
-LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
-{
- _speed = 1.0;
-}
+ for (samplecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ /* get the index into the input we should start with */
+ i = floor (distance);
+ float fractional_phase_part = fmod (distance, 1.0);
-LibSamplerateInterpolation::~LibSamplerateInterpolation()
-{
- for (size_t i = 0; i < state.size(); i++) {
- state[i] = src_delete (state[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)
-void
-LibSamplerateInterpolation::set_speed (double new_speed)
-{
- _speed = new_speed;
- for (size_t i = 0; i < state.size(); i++) {
- src_set_ratio (state[i], 1.0/_speed);
- }
-}
+ 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])));
-void
-LibSamplerateInterpolation::reset_state ()
-{
- printf("INTERPOLATION: reset_state()\n");
- for (size_t i = 0; i < state.size(); i++) {
- if (state[i]) {
- src_reset (state[i]);
- } else {
- state[i] = src_new (SRC_SINC_FASTEST, 1, &error);
+ distance += _speed + acceleration;
+ inm1 = input[i];
}
+
+ i = floor (distance);
+ phase[channel] = fmod (distance, 1.0);
+
+ } else {
+ /* used to calculate play-distance with acceleration (silent roll)
+ * (use same algorithm as real playback for identical rounding/floor'ing)
+ */
+ for (samplecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ distance += _speed + acceleration;
+ }
+ i = floor (distance);
+ phase[channel] = fmod (distance, 1.0);
}
-}
-void
-LibSamplerateInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size)
-{
- SRC_DATA* newdata = new SRC_DATA;
-
- /* Set up sample rate converter info. */
- newdata->end_of_input = 0 ;
-
- newdata->input_frames = input_buffer_size;
- newdata->output_frames = output_buffer_size;
-
- newdata->input_frames_used = 0 ;
- newdata->output_frames_gen = 0 ;
-
- newdata->src_ratio = 1.0/_speed;
-
- data.push_back (newdata);
- state.push_back (0);
-
- reset_state ();
+ return i;
}
-void
-LibSamplerateInterpolation::remove_channel_from ()
+/* CubicMidiInterpolation::distance is identical to
+ * return CubicInterpolation::interpolate (0, nframes, NULL, NULL);
+ */
+samplecnt_t
+CubicMidiInterpolation::distance (samplecnt_t nframes, bool /*roll*/)
{
- SRC_DATA* d = data.back ();
- delete d;
- data.pop_back ();
- if (state.back ()) {
- src_delete (state.back ());
+ assert (phase.size () == 1);
+
+ samplecnt_t i = 0;
+
+ double acceleration;
+ double distance = phase[0];
+
+ if (nframes < 3) {
+ /* no interpolation possible */
+ phase[0] = 0;
+ return nframes;
}
- state.pop_back ();
- reset_state ();
-}
-nframes_t
-LibSamplerateInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
-{
- if (!data.size ()) {
- printf ("ERROR: trying to interpolate with no channels\n");
- return 0;
+ if (_speed != _target_speed) {
+ acceleration = _target_speed - _speed;
+ } else {
+ acceleration = 0.0;
}
-
- data[channel]->data_in = input;
- data[channel]->data_out = output;
-
- data[channel]->input_frames = nframes * _speed;
- data[channel]->output_frames = nframes;
- data[channel]->src_ratio = 1.0/_speed;
-
- if ((error = src_process (state[channel], data[channel]))) {
- printf ("\nError : %s\n\n", src_strerror (error));
- exit (1);
+
+ for (samplecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ distance += _speed + acceleration;
}
-
- //printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used);
-
- return data[channel]->input_frames_used;
+
+ i = floor (distance);
+ phase[0] = fmod (distance, 1.0);
+
+ return i;
}