[frame_timecode] Fix UnboundedLocalError for strings with too many ":" characters

Fixes #476

Author: Breakthrough

scenedetect/frame_timecode.py

@@ -286,6 +286,8 @@ def _parse_timecode_string(self, input: str) -> int:
         # Timecode in string format 'HH:MM:SS[.nnn]' or 'MM:SS[.nnn]'
         elif input.find(":") >= 0:
             values = input.split(":")
+            if len(values) not in (2, 3):
+                raise ValueError("Invalid timecode (too many separators).")
             # Case of 'HH:MM:SS[.nnn]'
             if len(values) == 3:
                 hrs, mins = int(values[0]), int(values[1])

tests/test_frame_timecode.py

@@ -122,6 +122,13 @@ def test_timecode_string():
     assert FrameTimecode(timecode="00:00:02.0000", fps=1).frame_num == 2
     assert FrameTimecode(timecode="00:00:02.0001", fps=1).frame_num == 2
 
+    # MM:SS[.nnn] is also allowed
+    assert FrameTimecode(timecode="00:01", fps=1).frame_num == 1
+    assert FrameTimecode(timecode="00:01.9999", fps=1).frame_num == 2
+    assert FrameTimecode(timecode="00:02.0000", fps=1).frame_num == 2
+    assert FrameTimecode(timecode="00:02.0001", fps=1).frame_num == 2
+
+    # Conversion edge cases
     assert FrameTimecode(timecode="00:00:01", fps=10).frame_num == 10
     assert FrameTimecode(timecode="00:00:00.5", fps=10).frame_num == 5
     assert FrameTimecode(timecode="00:00:00.100", fps=10).frame_num == 1
@@ -135,6 +142,10 @@ def test_timecode_string():
     assert FrameTimecode(timecode="01:00:00.000", fps=1).frame_num == 3600
     assert FrameTimecode(timecode="01:00:00.001", fps=1).frame_num == 3600
 
+    # Check too many ":" characters (https://github.com/Breakthrough/PySceneDetect/issues/476)
+    with pytest.raises(ValueError):
+        FrameTimecode(timecode="01:01:00:00.001", fps=1)
+
 
 def test_get_frames():
     """Test FrameTimecode get_frames() method."""