X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Finterpolation.cc;h=3ba9253dee7016045c92108f2c9f1454fe2a331f;hb=9bf40bde3aed831791108bfccc4b1e10b071afdc;hp=a1c7c67d2ba5908f4cd8d63d1a81bcd1a78fab5c;hpb=86db1ebc5f49a06aa86585e36812a329fb582d20;p=ardour.git diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index a1c7c67d2b..3ba9253dee 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -1,232 +1,227 @@ -#include +/* + 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 + #include "ardour/interpolation.h" +#include "ardour/midi_buffer.h" using namespace ARDOUR; +using std::cerr; +using std::endl; -nframes_t -FixedPointLinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output) +CubicInterpolation::CubicInterpolation () + : valid_z_bits (0) { - // 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 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; - - for (nframes_t outsample = 0; outsample < nframes; ++outsample) { - i = phase >> 24; - Sample fractional_phase_part = (phase & fractional_part_mask) / binary_scaling_factor; - - if (input && output) { - // Linearly interpolate into the output buffer - // using fixed point math - output[outsample] = - input[i] * (1.0f - fractional_phase_part) + - input[i+1] * fractional_phase_part; - } - - phase += phi + phi_delta; - } - - last_phase[channel] = (phase & fractional_part_mask); - - // playback distance - return i; } -void -FixedPointLinearInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size) +samplecnt_t +CubicInterpolation::interpolate (int channel, samplecnt_t input_samples, Sample *input, samplecnt_t & output_samples, Sample *output) { - last_phase.push_back (0); -} + assert (input_samples > 0); + assert (output_samples > 0); + assert (input); + assert (output); + assert (phase.size () > channel); + + _speed = fabs (_speed); + + if (invalid (0)) { + + /* z[0] not set. Two possibilities + * + * 1) we have just been constructed or ::reset() + * + * 2) we were only given 1 sample after construction or + * ::reset, and stored it in z[1] + */ + + if (invalid (1)) { + + /* first call after construction or after ::reset */ + + switch (input_samples) { + case 1: + /* store one sample for use next time. We don't + * have enough points to interpolate or even + * compute the first z[0] value, but keep z[1] + * around. + */ + z[1] = input[0]; validate (1); + output_samples = 0; + return 0; + case 2: + /* store two samples for use next time, and + * compute a value for z[0] that will maintain + * the slope of the first actual segment. We + * still don't have enough samples to interpolate. + */ + z[0] = input[0] - (input[1] - input[0]); validate (0); + z[1] = input[0]; validate (1); + z[2] = input[1]; validate (2); + output_samples = 0; + return 0; + default: + /* We have enough samples to interpolate this time, + * but don't have a valid z[0] value because this is the + * first call after construction or ::reset. + * + * First point is based on a requirement to maintain + * the slope of the first actual segment + */ + z[0] = input[0] - (input[1] - input[0]); validate (0); + break; + } + } else { -void -FixedPointLinearInterpolation::remove_channel_from () -{ - last_phase.pop_back (); -} + /* at least one call since construction or + * after::reset, since we have z[1] set + * + * we can now compute z[0] as required + */ -void -FixedPointLinearInterpolation::reset() -{ - for (size_t i = 0; i <= last_phase.size(); i++) { - last_phase[i] = 0; - } -} + z[0] = z[1] - (input[0] - z[1]); validate (0); + /* we'll check the number of samples we've been given + in the next switch() statement below, and either + just save some more samples or actual interpolate + */ + } -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; + assert (is_valid (0)); } - - printf("phase before: %lf\n", phase[channel]); - distance = phase[channel]; - for (nframes_t outsample = 0; outsample < nframes; ++outsample) { - i = distance; - Sample fractional_phase_part = distance - i; - if (fractional_phase_part >= 1.0) { - fractional_phase_part -= 1.0; - i++; + + switch (input_samples) { + case 1: + /* one more sample of input. find the right vX to store + it in, and decide if we're ready to interpolate + */ + if (invalid (1)) { + z[1] = input[0]; validate (1); + /* still not ready to interpolate */ + output_samples = 0; + return 0; + } else if (invalid (2)) { + /* still not ready to interpolate */ + z[2] = input[0]; validate (2); + output_samples = 0; + return 0; + } else if (invalid (3)) { + z[3] = input[0]; validate (3); + /* ready to interpolate */ } - //printf("I: %u, distance: %lf, fractional_phase_part: %lf\n", i, distance, fractional_phase_part); - - if (input && output) { - // Linearly interpolate into the output buffer - output[outsample] = - input[i] * (1.0f - fractional_phase_part) + - input[i+1] * fractional_phase_part; + break; + case 2: + /* two more samples of input. find the right vX to store + them in, and decide if we're ready to interpolate + */ + if (invalid (1)) { + z[1] = input[0]; validate (1); + z[2] = input[1]; validate (2); + /* still not ready to interpolate */ + output_samples = 0; + return 0; + } else if (invalid (2)) { + z[2] = input[0]; validate (2); + z[3] = input[1]; validate (3); + /* ready to interpolate */ + } else if (invalid (3)) { + z[3] = input[0]; validate (3); + /* ready to interpolate */ } - //printf("distance before: %lf\n", distance); - distance += _speed + acceleration; - //printf("distance after: %lf, _speed: %lf\n", distance, _speed); + break; + + default: + /* caller has given us at least enough samples to interpolate a + single value. + */ + z[1] = input[0]; validate (1); + z[2] = input[1]; validate (2); + z[3] = input[2]; validate (3); } - - 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; -} -void -LinearInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size) -{ - phase.push_back (0.0); -} + /* ready to interpolate using z[0], z[1], z[2] and z[3] */ -void -LinearInterpolation::remove_channel_from () -{ - phase.pop_back (); -} + assert (is_valid (0)); + assert (is_valid (1)); + assert (is_valid (2)); + assert (is_valid (3)); + /* we can use up to (input_samples - 2) of the input, so compute the + * maximum number of output samples that represents. + * + * Remember that the expected common case here is to be given + * input_samples that is substantially larger than output_samples, + * thus allowing us to always compute output_samples in one call. + */ -void -LinearInterpolation::reset() -{ - for (size_t i = 0; i <= phase.size(); i++) { - phase[i] = 0.0; - } -} + const samplecnt_t output_from_input = floor ((input_samples - 2) / _speed); -LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0) -{ - _speed = 1.0; -} + /* limit output to either the caller's requested number or the number + * determined by the input size. + */ -LibSamplerateInterpolation::~LibSamplerateInterpolation() -{ - for (size_t i = 0; i < state.size(); i++) { - state[i] = src_delete (state[i]); - } -} + const samplecnt_t limit = std::min (output_samples, output_from_input); -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); - } -} + samplecnt_t outsample = 0; + double distance = phase[channel]; + samplecnt_t used = floor (distance); + samplecnt_t i = 0; -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); - } + while (outsample < limit) { + + i = floor (distance); + + /* this call may stop the loop from being vectorized */ + float fractional_phase_part = fmod (distance, 1.0); + + /* Cubically interpolate into the output buffer */ + output[outsample++] = z[1] + 0.5f * fractional_phase_part * + (z[2] - z[0] + fractional_phase_part * (4.0f * z[2] + 2.0f * z[0] - 5.0f * z[1] - z[3] + + fractional_phase_part * (3.0f * (z[1] - z[2]) - z[0] + z[3]))); + + distance += _speed; + + z[0] = z[1]; + z[1] = input[i]; + z[2] = input[i+1]; + z[3] = input[i+2]; } -} -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 (); + output_samples = outsample; + phase[channel] = fmod (distance, 1.0); + return i - used; } void -LibSamplerateInterpolation::remove_channel_from () +CubicInterpolation::reset () { - SRC_DATA* d = data.back (); - delete d; - data.pop_back (); - if (state.back ()) { - src_delete (state.back ()); - } - state.pop_back (); - reset_state (); + Interpolation::reset (); + valid_z_bits = 0; } -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; - } - - 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); - } - - //printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used); - - return data[channel]->input_frames_used; +samplecnt_t +CubicInterpolation::distance (samplecnt_t nsamples) +{ + assert (phase.size () > 0); + return floor (floor (phase[0]) + (_speed * nsamples)); }