Add exception on outside of boundaries subclip

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add background radius to text clips
 
 ### Changed <!-- for changes in existing functionality -->
+- Subclipping outside of clip boundaries now raise an exception
 
 ### Deprecated <!-- for soon-to-be removed features -->
 

moviepy/Clip.py

@@ -402,6 +402,7 @@ def subclipped(self, start_time=0, end_time=None):
                 + "should be smaller than the clip's "
                 + "duration (%.02f)." % self.duration
             )
+
 
         new_clip = self.time_transform(lambda t: t + start_time, apply_to=[])
 
@@ -422,6 +423,13 @@ def subclipped(self, start_time=0, end_time=None):
                 end_time = self.duration + end_time
 
         if end_time is not None:
+            if (self.duration is not None) and (end_time > self.duration):
+                raise ValueError(
+                    "end_time (%.02f) " % end_time
+                    + "should be smaller or equal to the clip's "
+                    + "duration (%.02f)." % self.duration
+                )
+
             new_clip.duration = end_time - start_time
             new_clip.end = new_clip.start + new_clip.duration
 

tests/test_Clip.py

@@ -184,6 +184,7 @@ def test_clip_copy(copy_func):
         (3, 3, None, ValueError),  # start_time == duration
         (3, 1, -1, 1),  # negative end_time
         (None, 1, -1, ValueError),  # negative end_time for clip without duration
+        (1, 0, 2, ValueError),  # end_time after video end should raise exception
     ),
 )
 def test_clip_subclip(duration, start_time, end_time, expected_duration):

tests/test_VideoClip.py

@@ -389,16 +389,17 @@ def test_afterimage(util):
 
 def test_add():
     clip = VideoFileClip("media/fire2.mp4")
-    new_clip = clip[0:1] + clip[2:3.2]
-    assert new_clip.duration == 2.2
-    assert np.array_equal(new_clip[1.1], clip[2.1])
+    print(clip.duration)
+    new_clip = clip[0:1] + clip[1.5:2]
+    assert new_clip.duration == 1.5
+    assert np.array_equal(new_clip[1.1], clip[1.6])
 
 
 def test_slice_tuples():
     clip = VideoFileClip("media/fire2.mp4")
-    new_clip = clip[0:1, 2:3.2]
-    assert new_clip.duration == 2.2
-    assert np.array_equal(new_clip[1.1], clip[2.1])
+    new_clip = clip[0:1, 1.5:2]
+    assert new_clip.duration == 1.5
+    assert np.array_equal(new_clip[1.1], clip[1.6])
 
 
 def test_slice_mirror():