X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Finterpolation.cc;h=9eee53cc232da7925a4961c89cecbc52e3512656;hb=e4b5a842117dfb7aa6e488bc97fecd7ec53234a3;hp=fccc805cb018917a0848e25f90fdbdb7d2a7f716;hpb=01d57ff3e7bea307ab43d5521f232f947a24e10f;p=ardour.git diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index fccc805cb0..9eee53cc23 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -1,5 +1,5 @@ /* - Copyright (C) 2012 Paul Davis + 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 @@ -21,6 +21,7 @@ #include #include "ardour/interpolation.h" +#include "ardour/midi_buffer.h" using namespace ARDOUR; @@ -47,7 +48,7 @@ LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input } if (input && output) { - // Linearly interpolate into the output buffer + // Linearly interpolate into the output buffer output[outsample] = input[i] * (1.0f - fractional_phase_part) + input[i+1] * fractional_phase_part; @@ -63,89 +64,104 @@ LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input framecnt_t CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output) { - // index in the input buffers - framecnt_t i = 0; - - double acceleration; - double distance = 0.0; - - if (_speed != _target_speed) { - acceleration = _target_speed - _speed; - } else { - acceleration = 0.0; - } + // index in the input buffers + framecnt_t i = 0; - distance = phase[channel]; + double acceleration; + double distance = phase[channel]; - if (nframes < 3) { - /* no interpolation possible */ + if (_speed != _target_speed) { + acceleration = _target_speed - _speed; + } else { + acceleration = 0.0; + } - for (i = 0; i < nframes; ++i) { - output[i] = input[i]; - } + if (nframes < 3) { + /* no interpolation possible */ - return nframes; - } + if (input && output) { + for (i = 0; i < nframes; ++i) { + output[i] = input[i]; + } + } - /* keep this condition out of the inner loop */ + phase[channel] = 0; + return nframes; + } - if (input && output) { + /* keep this condition out of the inner loop */ - Sample inm1; + 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]); - 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]; - } + for (framecnt_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); - for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { + // 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) - float f = floor (distance); - float fractional_phase_part = distance - f; + 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]))); - /* get the index into the input we should start with */ + distance += _speed + acceleration; + inm1 = input[i]; + } - i = lrintf (f); + i = floor (distance); + phase[channel] = fmod (distance, 1.0); - /* 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 ... - */ + } 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); + phase[channel] = fmod (distance, 1.0); + } - if (fractional_phase_part >= 1.0) { - fractional_phase_part -= 1.0; - ++i; - } + return 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) +/* CubicMidiInterpolation::distance is identical to + * return CubicInterpolation::interpolate (0, nframes, NULL, NULL); + */ +framecnt_t +CubicMidiInterpolation::distance (framecnt_t nframes, bool /*roll*/) +{ + assert (phase.size () == 1); - 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]))); + framecnt_t i = 0; - distance += _speed + acceleration; - inm1 = input[i]; - } + double acceleration; + double distance = phase[0]; - } else { + if (nframes < 3) { + /* no interpolation possible */ + phase[0] = 0; + return nframes; + } - /* not sure that this is ever utilized - it implies that one of the input/output buffers is missing */ + if (_speed != _target_speed) { + acceleration = _target_speed - _speed; + } else { + acceleration = 0.0; + } - for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { - distance += _speed + acceleration; - } - } + for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { + distance += _speed + acceleration; + } - i = floor(distance); - phase[channel] = distance - floor(distance); + i = floor (distance); + phase[0] = fmod (distance, 1.0); - return i; + return i; }