96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
#include <stdint.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "gate.h"
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#include <math.h>
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void gate_init(
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struct gate * gate
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) {
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gate->threshold = 0.0;
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gate->enable_calibration = false;
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gate->block_size = 1024;
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gate->hist_size = 256;
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gate->hist_idx = 0;
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gate->hist = malloc( sizeof(float) * gate->hist_size );
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gate->cur_block_count = 0;
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gate->cur_block_sum = 0.0;
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gate->is_active = false;
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gate->cur_gain = 1.0;
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gate->attack = 1.0 / 4096.0;
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gate->release = 1.0 / 4096.0;
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}
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void gate_process(
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struct gate * gate,
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size_t frame_size,
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float const * in,
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float * out
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) {
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float sum = 0.0;
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int last_frame = 0;
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for( size_t i = 0; i < frame_size; ++i ) {
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gate->cur_block_sum += fabs( in[i] );
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gate->cur_block_count += 1;
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if( gate->cur_block_count >= gate->block_size ) {
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printf("new block sum [%lu] (frame %lu) : %f\n", gate->hist_idx, i, gate->cur_block_sum);
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if( gate->cur_block_sum > 20.0 ) {
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gate->is_active = true;
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} else {
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gate->is_active = false;
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}
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gate->hist[ gate->hist_idx ] = gate->cur_block_sum;
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gate->hist_idx = (gate->hist_idx + 1) % gate->hist_size;
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gate->cur_block_sum = 0.0;
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gate->cur_block_count = 0;
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last_frame = i;
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}
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}
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/*
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unsigned enable_pos = gate->is_active ? 0 : frame_size;
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unsigned disable_pos = gate->is_active ? frame_size : 0;
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unsigned blocks_per_buffer = frame_size / gate->block_size;
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/* start from last block sum and iterate backwards to find
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* the timepoint where a block sum crosses the threshold
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* /
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unsigned i = gate->hist_idx;
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while( last_frame > 0 ) {
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if( gate->hist[ i ] < gate->threshold ) {
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disable_pos = last_frame;
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}
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last_frame -= gate->block_size;
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i = (i - 1) % gate->hist_size;
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}
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*/
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for( size_t i = 0; i < frame_size; ++i ) {
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if( gate->is_active ) {
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gate->cur_gain += gate->attack;
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if( gate->cur_gain > 1.0 ) {
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gate->cur_gain = 1.0;
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}
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} else {
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gate->cur_gain -= gate->attack;
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if( gate->cur_gain < 0.0 ) {
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gate->cur_gain = 0.0;
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}
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}
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out[i] = in[i] * gate->cur_gain;
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}
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}
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