mirror of
https://github.com/cjfranko/NTP-Timeturner.git
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174 lines
No EOL
6 KiB
C++
174 lines
No EOL
6 KiB
C++
/* Linear Timecode for Audio Library for Teensy 3.x / 4.x
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Copyright (c) 2019, Frank Bösing, f.boesing (at) gmx.de
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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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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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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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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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/*
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https://forum.pjrc.com/threads/41584-Audio-Library-for-Linear-Timecode-(LTC)
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LTC example audio at: https://www.youtube.com/watch?v=uzje8fDyrgg
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Adapted by Chris Frankland-Wright 2025 for Teensy Audio Shield Input with autodetect FPS for the NTP-TimeTurner Project
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*/
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#include <Arduino.h>
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#include <Audio.h>
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#include "analyze_ltc.h"
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// —— Configuration ——
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const float FORCE_FPS = 0.0f; // 0 → auto‑detect
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const int FRAME_OFFSET = 4; // compensation in frames
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const unsigned long LOSS_TIMEOUT = 1000UL; // ms before we go into LOST
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const unsigned long BLINK_PERIOD[3] = {2000,100,500}; // NO_LTC, ACTIVE, LOST
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AudioInputI2S i2s1;
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AudioAnalyzeLTC ltc1;
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AudioControlSGTL5000 sgtl5000;
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AudioConnection patchCord(i2s1, 0, ltc1, 0);
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enum State { NO_LTC=0, LTC_ACTIVE, LTC_LOST };
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State ltcState = NO_LTC;
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bool ledOn = false;
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unsigned long lastDecode = 0;
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unsigned long lastBlink = 0;
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// FPS detection
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float currentFps = 25.0f;
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float periodMs = 0;
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const float SMOOTH_ALPHA = 0.1f;
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unsigned long lastDetectTs = 0;
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// free‑run
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long freeAbsFrame = 0;
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unsigned long lastFreeRun = 0;
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void setup() {
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Serial.begin(115200);
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AudioMemory(12);
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sgtl5000.enable();
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sgtl5000.inputSelect(AUDIO_INPUT_LINEIN);
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pinMode(LED_BUILTIN, OUTPUT);
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}
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void loop() {
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unsigned long now = millis();
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// compute framePeriod from currentFps
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unsigned long framePeriod = (unsigned long)(1000.0f / currentFps + 0.5f);
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// 1) If in ACTIVE and we've gone > LOSS_TIMEOUT w/o decode, enter LOST
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if (ltcState == LTC_ACTIVE && (now - lastDecode) >= LOSS_TIMEOUT) {
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ltcState = LTC_LOST;
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// bump freeAbsFrame by 1 second worth of frames:
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int nominal = (currentFps>29.5f) ? 30 : int(currentFps+0.5f);
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long dayFrames= 24L*3600L*nominal;
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freeAbsFrame = (freeAbsFrame + nominal) % dayFrames;
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// reset free‑run timer so we start next tick fresh
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lastFreeRun = now;
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}
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// 2) Handle incoming LTC frame
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if (ltc1.available()) {
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ltcframe_t frame = ltc1.read();
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int h = ltc1.hour(&frame),
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m = ltc1.minute(&frame),
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s = ltc1.second(&frame),
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f = ltc1.frame(&frame);
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// — FPS detect or force —
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if (FORCE_FPS > 0.0f) {
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currentFps = FORCE_FPS;
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} else {
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if (lastDetectTs) {
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float dt = now - lastDetectTs;
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periodMs = periodMs==0 ? dt : (SMOOTH_ALPHA*dt + (1-SMOOTH_ALPHA)*periodMs);
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float meas = 1000.0f/periodMs;
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const float choices[3] = {24.0f,25.0f,29.97f};
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float bestD=1e6, pick=25.0f;
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for (auto c: choices) {
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float d = fabs(meas-c);
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if (d < bestD) { bestD=d; pick=c; }
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}
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currentFps = pick;
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}
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lastDetectTs = now;
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}
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// — pack + offset + wrap —
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int nominal = (currentFps>29.5f) ? 30 : int(currentFps+0.5f);
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long dayFrames = 24L*3600L*nominal;
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long absF = ((long)h*3600 + m*60 + s)*nominal + f + FRAME_OFFSET;
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absF = (absF % dayFrames + dayFrames) % dayFrames;
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// — reset anchors & state —
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freeAbsFrame = absF;
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lastFreeRun = now;
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lastDecode = now;
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ltcState = LTC_ACTIVE;
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// — print LOCK —
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long totSec = absF/nominal;
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int outF = absF % nominal;
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int outS = totSec % 60;
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long totMin = totSec/60;
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int outM = totMin % 60;
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int outH = (totMin/60) % 24;
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bool isDF = ltc1.bit10(&frame);
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char sep = isDF?';':':';
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Serial.printf("[LOCK] %02d:%02d:%02d%c%02d | %.2ffps\r\n",
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outH,outM,outS,sep,outF,currentFps);
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// — LED → ACTIVE immediately —
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lastBlink = now;
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ledOn = true;
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digitalWrite(LED_BUILTIN, HIGH);
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}
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// 3) If in LOST, do free‑run printing
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else if (ltcState == LTC_LOST) {
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if ((now - lastFreeRun) >= framePeriod) {
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freeAbsFrame = (freeAbsFrame + 1) % (24L*3600L*((int)(currentFps+0.5f)));
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lastFreeRun += framePeriod;
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// — print FREE —
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int nominal = (currentFps>29.5f) ? 30 : int(currentFps+0.5f);
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long totSec = freeAbsFrame/nominal;
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int outF = freeAbsFrame % nominal;
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int outS = totSec % 60;
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long totMin = totSec/60;
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int outM = totMin % 60;
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int outH = (totMin/60)%24;
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Serial.printf("[FREE] %02d:%02d:%02d:%02d | %.2ffps\r\n",
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outH,outM,outS,outF,currentFps);
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}
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}
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// 4) LED heartbeat
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unsigned long bp = BLINK_PERIOD[ltcState];
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if ((now - lastBlink) >= (bp/2)) {
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ledOn = !ledOn;
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digitalWrite(LED_BUILTIN, ledOn);
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lastBlink = now;
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}
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} |