X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=libs%2Fardour%2Finterpolation.cc;h=3b21fe171819453ab463ef97e92256c25a3ff27d;hb=8488d8f6a53d3385893a435481cb60ed21c21ea0;hp=e0035ea11b264b0eab23b037a2f71025c74c22fd;hpb=272c1a40db7c965664b256f7f5487dd224bfd413;p=ardour.git diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index e0035ea11b..3b21fe1718 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -1,306 +1,190 @@ +/* + 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 #include #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) + +framecnt_t +LinearInterpolation::interpolate (int channel, framecnt_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; + framecnt_t i = 0; + + double acceleration = 0; + + if (_speed != _target_speed) { + acceleration = _target_speed - _speed; + } + + for (framecnt_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) +framecnt_t +CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output) { // index in the input buffers - nframes_t i = 0; - + framecnt_t i = 0; + double acceleration; double distance = 0.0; - + 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); + + 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; - - if (input) { - // 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) { -LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0) -{ - _speed = 1.0; -} + Sample inm1; -LibSamplerateInterpolation::~LibSamplerateInterpolation() -{ - for (size_t i = 0; i < state.size(); i++) { - state[i] = src_delete (state[i]); - } -} + 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]; + } -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); - } -} + for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { -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); + float f = floor (distance); + float fractional_phase_part = distance - f; + + /* get the index into the input we should start with */ + + 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; } + i = floor(distance); } -} -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 () +framecnt_t +CubicMidiInterpolation::distance (framecnt_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); + + framecnt_t i = 0; + + double acceleration; + double distance = 0.0; + + if (nframes < 3) { + 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; + } + + distance = phase[0]; + + for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { + distance += _speed + acceleration; } - - 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); + + if (roll) { + phase[0] = distance - floor(distance); } - - //printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used); - - return data[channel]->input_frames_used; + + i = floor(distance); + + return i; }