X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Finterpolation.cc;h=ccaaca7e76322f13ff5097e6d1eeaaa0b203ecc4;hb=3ddfc762248bbad41645998781584e2e70549b93;hp=a1c7c67d2ba5908f4cd8d63d1a81bcd1a78fab5c;hpb=86db1ebc5f49a06aa86585e36812a329fb582d20;p=ardour.git diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index a1c7c67d2b..ccaaca7e76 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -5,228 +5,128 @@ using namespace ARDOUR; -nframes_t -FixedPointLinearInterpolation::interpolate (int channel, nframes_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 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) -{ - last_phase.push_back (0); -} - -void -FixedPointLinearInterpolation::remove_channel_from () -{ - last_phase.pop_back (); -} -void -FixedPointLinearInterpolation::reset() +framecnt_t +LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output) { - for (size_t i = 0; i <= last_phase.size(); i++) { - last_phase[i] = 0; - } -} + // index in the input buffers + framecnt_t i = 0; + double acceleration = 0; -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; } - - 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; + + 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++; } - //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] = + output[outsample] = input[i] * (1.0f - fractional_phase_part) + input[i+1] * fractional_phase_part; } - //printf("distance before: %lf\n", distance); - distance += _speed + acceleration; - //printf("distance after: %lf, _speed: %lf\n", distance, _speed); } - - printf("before assignment: i: %d, distance: %lf\n", i, distance); + + double const distance = phase[channel] + nframes * (_speed + acceleration); 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]); - + phase[channel] = distance - i; return i; } -void -LinearInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size) +framecnt_t +CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output) { - phase.push_back (0.0); -} + // index in the input buffers + framecnt_t i = 0; -void -LinearInterpolation::remove_channel_from () -{ - phase.pop_back (); -} + double acceleration; + double distance = 0.0; + if (_speed != _target_speed) { + acceleration = _target_speed - _speed; + } else { + acceleration = 0.0; + } -void -LinearInterpolation::reset() -{ - for (size_t i = 0; i <= phase.size(); i++) { - phase[i] = 0.0; - } -} + distance = phase[channel]; -LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0) -{ - _speed = 1.0; -} + if (nframes < 3) { + /* no interpolation possible */ -LibSamplerateInterpolation::~LibSamplerateInterpolation() -{ - for (size_t i = 0; i < state.size(); i++) { - state[i] = src_delete (state[i]); - } -} + for (i = 0; i < nframes; ++i) { + output[i] = input[i]; + } -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); - } -} + return nframes; + } -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); - } - } -} + /* keep this condition out of the inner loop */ -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 (); -} + if (input && output) { -void -LibSamplerateInterpolation::remove_channel_from () -{ - SRC_DATA* d = data.back (); - delete d; - data.pop_back (); - if (state.back ()) { - src_delete (state.back ()); - } - state.pop_back (); - reset_state (); -} + Sample inm1; -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; + 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) { + + 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]; + } + + } else { + + /* not sure that this is ever utilized - it implies that one of the input/output buffers is missing */ + + for (framecnt_t outsample = 0; outsample < nframes; ++outsample) { + distance += _speed + acceleration; + } + } + + i = floor(distance); + phase[channel] = distance - floor(distance); + + return i; }