Fix issue Zulko#2269 with PR Zulko#2262, thanks to @Implosiv3

moviepy/video/VideoClip.py

@@ -1404,7 +1404,7 @@ class ColorClip(ImageClip):
     ----------
 
     size
-      Size (width, height) in pixels of the clip.
+      Size tuple (width, height) in pixels of the clip.
 
     color
       If argument ``is_mask`` is False, ``color`` indicates

moviepy/video/compositing/CompositeVideoClip.py

@@ -336,7 +336,7 @@ def frame_function(t):
             return clips[i].get_frame(t - timings[i])
 
         def get_mask(clip):
-            mask = clip.mask or ColorClip([1, 1], color=1, is_mask=True)
+            mask = clip.mask or ColorClip(clip.size, color=1, is_mask=True)
             if mask.duration is None:
                 mask.duration = clip.duration
             return mask

tests/test_compositing.py

@@ -293,5 +293,13 @@ def test_slide_out():
             assert n_reds == n_reds_expected
 
 
+def test_concatenate_with_masks(util):
+    video_without_mask = ColorClip(size=(10, 10), color=(255, 0, 0)).with_duration(1).with_fps(1)
+    video_with_mask = ColorClip(size=(5, 5), color=(0, 255, 0)).with_duration(1).with_fps(1).with_mask()
+
+    output = os.path.join(util.TMP_DIR, "test_concatenate_with_masks.mp4")
+    concatenate_videoclips([video_without_mask, video_with_mask]).write_videofile(output)
+
+
 if __name__ == "__main__":
     pytest.main()