diff options
author | Hans Baier <hansfbaier@googlemail.com> | 2009-06-23 09:50:39 +0000 |
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committer | Hans Baier <hansfbaier@googlemail.com> | 2009-06-23 09:50:39 +0000 |
commit | dd84d5312e2b09538aa98a1b21e84a458a2c145c (patch) | |
tree | 3c4b3226a1b8ceb15b19410dbe0204e2683f50e5 /libs/ardour/interpolation.cc | |
parent | 47e56905523cb9269a19300d2b468118dda3a161 (diff) |
Xinterpolation.*: Add old fixed point and double linear interpolation as alternatives
git-svn-id: svn://localhost/ardour2/branches/3.0@5258 d708f5d6-7413-0410-9779-e7cbd77b26cf
Diffstat (limited to 'libs/ardour/interpolation.cc')
-rw-r--r-- | libs/ardour/interpolation.cc | 141 |
1 files changed, 137 insertions, 4 deletions
diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc index 3d2f754da9..9b2ff03e23 100644 --- a/libs/ardour/interpolation.cc +++ b/libs/ardour/interpolation.cc @@ -4,8 +4,141 @@ using namespace ARDOUR; -LibSamplerateInterpolation::LibSamplerateInterpolation() : _speed (1.0L), state (0) +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() +{ + for(int i = 0; i <= last_phase.size(); i++) { + last_phase[i] = 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; + 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] = + 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); + 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); +} + +void +LinearInterpolation::remove_channel_from () +{ + phase.pop_back (); +} + + +void +LinearInterpolation::reset() +{ + for(int i = 0; i <= phase.size(); i++) { + phase[i] = 0.0; + } +} + +LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0) { + _speed = 1.0; } LibSamplerateInterpolation::~LibSamplerateInterpolation() @@ -77,12 +210,12 @@ LibSamplerateInterpolation::interpolate (int channel, nframes_t nframes, Sample return 0; } - data[channel]->data_in = input; - data[channel]->data_out = output; + 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; + data[channel]->src_ratio = 1.0/_speed; if ((error = src_process (state[channel], data[channel]))) { printf ("\nError : %s\n\n", src_strerror (error)); |