don't treat unknown audio as an audio-bearing stream

A recording row with NULL has_audio (ffprobe failed and the cv2 fallback can't report audio) marked the whole stream as audio-bearing, so every confirmed video-only row on it was dropped as a glitch. A stream now counts as audio-bearing only when a row is known to carry audio.

frigate/test/test_recording_coverage.py

@@ -13,6 +13,7 @@ from frigate.models import Recordings
 from frigate.util.recording_coverage import (
     _rows_query,
     coverage_spans,
+    null_audio_glitches,
     plan_clip,
     realized_timeline,
     resolve_coverage,
@@ -166,6 +167,22 @@ class TestRecordingCoverage(CoverageDbTestCase):
         expected = int(5 * 1024 * 1024 * 8 / 10)
         assert summary["main"]["bitrate"] == expected
 
+    def test_unknown_audio_row_keeps_video_only_stream(self):
+        self._insert("s1", 1000.0, 1010.0, "sub", has_audio=False)
+        self._insert("s2", 1010.0, 1020.0, "sub", has_audio=None)
+        self._insert("s3", 1020.0, 1030.0, "sub", has_audio=False)
+        kept = null_audio_glitches(resolve_coverage("front_door", 1000.0, 1030.0))
+        self.assertEqual(
+            [i.sub.path for i in kept], [f"/tmp/s{n}.mp4" for n in (1, 2, 3)]
+        )
+
+    def test_video_only_glitch_dropped_on_audio_stream(self):
+        self._insert("s1", 1000.0, 1010.0, "sub", has_audio=True)
+        self._insert("s2", 1010.0, 1020.0, "sub", has_audio=False)
+        self._insert("s3", 1020.0, 1030.0, "sub", has_audio=None)
+        kept = null_audio_glitches(resolve_coverage("front_door", 1000.0, 1030.0))
+        self.assertEqual([i.sub.path for i in kept], ["/tmp/s1.mp4", "/tmp/s3.mp4"])
+
     def test_other_camera_rows_excluded(self):
         self._insert("m1", 1000.0, 1010.0, "main")
         self._insert("o1", 1000.0, 1010.0, "main", camera="back_yard")

frigate/util/recording_coverage.py

@@ -204,11 +204,12 @@ def coverage_spans(intervals: list[CoverageInterval]) -> list[dict[str, Any]]:
 def stream_has_audio(intervals: list[CoverageInterval], main: bool) -> bool:
     """Whether a stream is audio-bearing over a coverage window.
 
-    A stream counts as audio-bearing unless EVERY one of its rows reports
-    has_audio False; NULL (legacy or undetermined) counts as audio.
+    A stream counts as audio-bearing only when one of its rows is known
+    to carry audio. A NULL row (legacy, or a segment ffprobe could not
+    read) proves nothing either way.
     """
     return any(
-        row is not None and row.has_audio is not False
+        row is not None and row.has_audio is True
         for row in ((interval.main if main else interval.sub) for interval in intervals)
     )