Dooho Yi
91f92c0e6c
migration from 'smp_v1p0' dev. for 'sampler' -> skip irrelavant note msg. and keep playing
95 lines
3.6 KiB
C++
95 lines
3.6 KiB
C++
/* Audio Library for Teensy 3.X
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* Copyright (c) 2015, Hedde Bosman
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*
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* Development of this audio library was funded by PJRC.COM, LLC by sales of
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
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* open source software by purchasing Teensy or other PJRC products.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice, development funding notice, and this permission
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* notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <Arduino.h>
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#include "effect_midside.h"
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void AudioEffectMidSide::update(void)
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{
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audio_block_t *blocka, *blockb;
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uint32_t *pa, *pb, *end;
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uint32_t a12, a34; //, a56, a78;
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uint32_t b12, b34; //, b56, b78;
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blocka = receiveWritable(0); // left (encoding) or mid (decoding)
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blockb = receiveWritable(1); // right (encoding) or side (decoding)
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if (!blocka || !blockb) {
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if (blocka) release(blocka); // maybe an extra if statement here but if one
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if (blockb) release(blockb); // of the blocks is NULL then it's trouble anyway
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return;
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}
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#if defined(KINETISK)
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pa = (uint32_t *)(blocka->data);
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pb = (uint32_t *)(blockb->data);
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end = pa + AUDIO_BLOCK_SAMPLES/2;
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if (encoding) {
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while (pa < end) {
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// mid[i] = (blocka[i] + blockb[i])/2; // div2 to prevent overflows
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// side[i] = (blocka[i] - blockb[i])/2; // div2 to prevent overflows
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// L[i] = (mid[i] + side[i])/2;
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// R[i] = (mid[i] - side[i])/2;
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a12 = signed_halving_add_16_and_16(*pa, *pb); // mid12
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a34 = signed_halving_add_16_and_16(*(pa+1), *(pb+1)); //mid34
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b12 = signed_halving_subtract_16_and_16(*pa, *pb); // side12
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b34 = signed_halving_subtract_16_and_16(*(pa+1), *(pb+1)); // side34
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*pa++ = a12;
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*pa++ = a34;
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*pb++ = b12;
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*pb++ = b34;
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}
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} else {
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while (pa < end) {
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// L[i] = mid[i] + side[i]);
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// R[i] = mid[i] - side[i]);
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// Because the /2 has already been applied in the encoding,
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// we shouldn't have to add it here.
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// However... because of the posibility that the user has
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// modified mid or side such that
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// it could overflow, we have to:
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// a) preventively do a (x/2+y/2)*2 again, causing bit reduction
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// or b) perform saturation or something.
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// While (b) could produce artifacts if saturated, I'll go for
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// that option to preserve precision
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// QADD16 and QSUB16 perform saturating add/sub
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a12 = signed_add_16_and_16(*pa, *pb); // left12
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a34 = signed_add_16_and_16(*(pa+1), *(pb+1)); // left34
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b12 = signed_subtract_16_and_16(*pa, *pb); // right12
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b34 = signed_subtract_16_and_16(*(pa+1), *(pb+1)); // right34
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*pa++ = a12;
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*pa++ = a34;
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*pb++ = b12;
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*pb++ = b34;
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}
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}
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transmit(blocka, 0); // mid (encoding) or left (decoding)
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transmit(blockb, 1); // side (encoding) or right (decoding)
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#endif
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release(blocka);
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release(blockb);
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}
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