Take into account rotation metadata to define video size

CHANGELOG.md

@@ -52,6 +52,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed `clip.preview()` crashing at exit when running inside Jupyter Notebook in Windows [\#1537](https://github.com/Zulko/moviepy/pull/1537)
 - Fixed rotate FX not being applied to mask images [\#1399](https://github.com/Zulko/moviepy/pull/1399)
 - Fixed opacity error blitting VideoClips [\#1552](https://github.com/Zulko/moviepy/pull/1552)
+- Fixed rotation metadata of input not being taken into account rendering VideoClips [\#577](https://github.com/Zulko/moviepy/pull/577)
 
 
 ## [v2.0.0.dev2](https://github.com/zulko/moviepy/tree/v2.0.0.dev2) (2020-10-05)

moviepy/video/io/ffmpeg_reader.py

@@ -37,7 +37,12 @@ def __init__(
         )
         self.fps = infos["video_fps"]
         self.size = infos["video_size"]
-        self.rotation = infos.get("video_rotation", 0)
+
+        # ffmpeg automatically rotates videos if rotation information is
+        # available, so exchange width and height
+        self.rotation = abs(infos.get("video_rotation", 0))
+        if self.rotation in [90, 270]:
+            self.size = [self.size[1], self.size[0]]
 
         if target_resolution:
             if None in target_resolution:

tests/test_ffmpeg_reader.py

@@ -14,6 +14,7 @@
     FFmpegInfosParser,
     ffmpeg_parse_infos,
 )
+from moviepy.video.io.VideoFileClip import VideoFileClip
 from moviepy.video.VideoClip import BitmapClip
 
 from tests.test_helper import TMP_DIR
@@ -299,6 +300,27 @@ def test_ffmpeg_parse_infos_metadata_with_attached_pic():
     assert len(d["metadata"].keys()) == 7
 
 
+def test_ffmpeg_parse_video_rotation():
+    d = ffmpeg_parse_infos("media/rotated-90-degrees.mp4")
+    assert d["video_rotation"] == 90
+    assert d["video_size"] == [1920, 1080]
+
+
+def test_correct_video_rotation():
+    """See https://github.com/Zulko/moviepy/pull/577"""
+    clip = VideoFileClip("media/rotated-90-degrees.mp4").subclip(0.2, 0.4)
+
+    corrected_rotation_filename = os.path.join(
+        TMP_DIR,
+        "correct_video_rotation.mp4",
+    )
+    clip.write_videofile(corrected_rotation_filename)
+
+    d = ffmpeg_parse_infos(corrected_rotation_filename)
+    assert "video_rotation" not in d
+    assert d["video_size"] == [1080, 1920]
+
+
 def test_ffmpeg_parse_infos_multiline_metadata():
     """Check that the parser can parse multiline metadata values."""
     infos = """Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/110_PREV_FINAL.mov':