SC timecode: LTC Listen.app decodes the tracks' LTC from SoundGrid; PROP shows TIMECODE LOST mid-song

ProPresenter can't report its timecode, so LTC Listen (a small app on SC's ProPresenter Mac, microphone
permission allowed on site 2026-10-26, LaunchAgent org.waterschurch.ltc-listen) reads the same SoundGrid
input (com_waves_WCAudioGridEngine, channel 1) and writes the running timecode. The prop guard logs a drop
in a song (2 s without timecode) with the song and timecode, and serves 127.0.0.1:8095/timecode, which SC's
PROP key checks (TIMECODE LOST). Decoder tested against generated LTC and live (00:27:37:28).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_prop_guard.py

@@ -88,5 +88,39 @@ class TestGuard(unittest.TestCase):
         self.assertEqual(self.fake.calls.count("/v1/presentation/active/timeline/play"), 1)
 
 
+class TestTimecode(unittest.TestCase):
+    def test_timecode_lost_in_a_song_and_back(self):
+        fake, clock = FakeProP(), [1000.0]
+        fake.layout = "Worship"
+        orig_api, orig_ltc = pg.api, pg.Guard.ltc
+        ltc = {"running": True, "tc": "00:01:00:00"}
+        pg.api = fake
+        pg.Guard.ltc = lambda self: dict(ltc, time=clock[0])
+        try:
+            g = pg.Guard(now=lambda: clock[0])
+            def at(t):
+                clock[0] = 1000.0 + t
+                g.tick()
+            at(0)
+            at(5)
+            ltc["running"] = False                           # gone mid-song
+            at(6)
+            self.assertFalse(g.lost)                         # not yet 2 s
+            at(8.5)
+            self.assertTrue(g.lost)
+            self.assertEqual(g.state["ltc_drops"][0]["song"], "Jehovah")
+            ltc["running"] = True
+            at(10)
+            self.assertFalse(g.lost)
+            self.assertIn("back", g.state["ltc_drops"][0])
+            fake.song = None                                 # between songs no timecode is fine
+            ltc["running"] = False
+            at(20)
+            at(30)
+            self.assertFalse(g.lost)
+        finally:
+            pg.api, pg.Guard.ltc = orig_api, orig_ltc
+
+
 if __name__ == "__main__":
     unittest.main()