Diff: frameRates.cpp

Revision:

0:97661408d0f9

Child:

9:7214e3c3e5f8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frameRates.cpp	Fri Jan 15 11:49:01 2021 +0000
@@ -0,0 +1,93 @@
+#include "LTCApp.h"
+
+frameRates::frameRates() {
+    setRate(1);
+}
+
+void frameRates::setRate(int index) {
+    _currentRate = frameRateInfo::FrameRates[index];
+_currentPeriod = frameRateInfo::FramePeriods[index];
+_currentIndex = index;
+TimeSinceLastFrameWrap =  frameRateInfo::FramePeriods[index];
+}
+
+bool frameRates::isSyncable() {
+  if (_currentIndex < 2) // 0 or 1
+    return false;
+  if (((_currentIndex == 4) || (_currentIndex == 9)) && !_currentDrop)
+    return false;
+  return true;
+}
+
+
+const char *frameRates::frameRateString() {
+  switch (_currentIndex) {
+  case 0:
+  default:
+    return "Unknown";
+  case 1:
+    return "23.976";
+  case 2:
+    return "24";
+  case 3:
+    return "25";
+  case 4:
+    return _currentDrop ? "29.97 Drop" : "29.97";
+  case 5:
+    return "30";
+  case 6:
+    return "47.95";
+  case 7:
+    return "48";
+  case 8:
+    return "50";
+  case 9:
+    return _currentDrop ? "59.94 Drop" : "59.94";
+  case 10:
+    return "60";
+  }
+}
+
+
+long frameRates::getOffsetFromSecondStart(int minutes, int seconds, int frame,
+                              int rateIndex, bool frameDrop){
+  if (!frameDrop) {
+    return frameRateInfo::FramePeriods[rateIndex] *
+           frame; // for non frame drops all second starts are perfect
+                  // not true for non-integer rates but for non-drop versions we
+                  // don't try to sync to those.
+  } else {
+    int MinutesSinceLastSync = minutes % 10;
+    const int framesPerMinute = 30 * 59 + 28;
+
+    double indicatedTimeSinceLastSync =
+        (MinutesSinceLastSync * framesPerMinute + seconds * 30 + frame) *
+        frameRateInfo::FramePeriods[rateIndex];
+    double framesMismatch =
+        (MinutesSinceLastSync * framesPerMinute + seconds * 30) -
+        (frameRateInfo::FrameRates[rateIndex] * (MinutesSinceLastSync * 60 + seconds));
+    double timeErrorAtSecondStart = framesMismatch * frameRateInfo::FramePeriods[rateIndex];
+    double timeThisSecond = frame * frameRateInfo::FramePeriods[rateIndex];
+    return (long)(timeThisSecond + timeErrorAtSecondStart + 0.5);
+  }
+}
+
+long frameRates::getOffsetFromSecondStart(int minutes, int seconds, int frame){
+  if (!_currentDrop) {
+    return _currentPeriod * frame; // for non frame drops all second starts are perfect
+                  // not true for non-integer rates but for non-drop versions we
+                  // don't try to sync to those.
+  } else {
+    int MinutesSinceLastSync = minutes % 10;
+    const int framesPerMinute = 30 * 59 + 28;
+
+    double indicatedTimeSinceLastSync =
+        (MinutesSinceLastSync * framesPerMinute + seconds * 30 + frame) * _currentPeriod;
+    double framesMismatch =
+        (MinutesSinceLastSync * framesPerMinute + seconds * 30) - (_currentRate * (MinutesSinceLastSync * 60 + seconds));
+    double timeErrorAtSecondStart = framesMismatch * _currentPeriod;
+    double timeThisSecond = frame * _currentPeriod;
+    return (long)(timeThisSecond + timeErrorAtSecondStart + 0.5);
+  }
+}
+