Preserve phase when sampling 50 fps from a 60 fps camera

tools/chatgui-android/app/src/main/java/com/utun/chat/data/CallVideoCadence.kt

@@ -9,7 +9,7 @@ internal class CallVideoCadence(private val fps: Int) {
         lastPts = pts
         val scaled = pts * fps
         if (next >= 0 && scaled < next - 250_000) return false
-        next = if (next < 0 || scaled - next > 250_000) scaled + 1_000_000 else next + 1_000_000
+        next = if (next < 0 || scaled - next > 1_000_000) scaled + 1_000_000 else next + 1_000_000
         return true
     }
 }

tools/chatgui/src/call_video_cadence.h

@@ -13,7 +13,7 @@ public:
         lastPts = pts;
         const int64_t scaled = pts * fps;
         if (next >= 0 && scaled < next - 250000) return false;
-        next = next < 0 || scaled - next > 250000 ? scaled + 1000000 : next + 1000000;
+        next = next < 0 || scaled - next > 1000000 ? scaled + 1000000 : next + 1000000;
         return true;
     }
 };

tools/chatgui/tests/test_call_camera_capture.cpp

@@ -118,7 +118,7 @@ private slots:
         qputenv("UTUN_CAMERA_TEST_LOG", path.toUtf8());
     }
     void captureCadence() {
-        for (int input : {50, 100, 330}) for (int output : {30, 50, 60}) {
+        for (int input : {50, 60, 100, 330}) for (int output : {30, 50, 60}) {
             if (output > input) continue;
             CallVideoCadence cadence(output); unsigned accepted = 0;
             for (int i = 0; i < input * 3; ++i) if (cadence.accept(1000000 + i * 1000000ll / input)) ++accepted;