Correctly set movie duration for conversion (#818)

* Finding correct duration for movie when converting a mpg movie.

* Adding testing for update to converting MPEG movie.

* PEP8

act/tests/sample_files.py

@@ -8,6 +8,7 @@
 from arm_test_data import DATASETS
 
 # Single files
+EXAMPLE_MPEG = DATASETS.fetch('nsacamskyradmovieC1.a1.20240401.100300.mpg')
 EXAMPLE_MET1 = DATASETS.fetch('sgpmetE13.b1.20190101.000000.cdf')
 EXAMPLE_MET_SAIL = DATASETS.fetch('gucmetM1.b1.20230301.000000.cdf')
 EXAMPLE_MET_CSV = DATASETS.fetch('sgpmetE13.b1.20210401.000000.csv')

act/utils/io_utils.py

@@ -8,8 +8,8 @@
 import types
 
 try:
+    import moviepy.editor as moviepy_editor
     import moviepy.video.io.ImageSequenceClip
-    from moviepy.video.io.VideoFileClip import VideoFileClip
 
     MOVIEPY_AVAILABLE = True
 except (ImportError, RuntimeError):
@@ -337,11 +337,35 @@ def generate_movie(images, write_filename=None, fps=10, **kwargs):
     write_directory.mkdir(parents=True, exist_ok=True)
 
     if IS_MOVIE:
-        with VideoFileClip(images) as clip:
-            # Not sure why but need to set the duration of the clip with subclip() to write
-            # the full file out.
-            clip = clip.subclip(t_start=clip.start, t_end=clip.end * clip.fps)
-            clip.write_videofile(str(write_filename), fps=fps, **kwargs)
+        with moviepy_editor.VideoFileClip(images) as clip:
+            # There can be an issue converting mpeg to other movie format because the
+            # duration parameter in the movie file is not set. So moviepy guesses and
+            # can get the duration wrong. This will find the correct duration (to 0.1 seconds)
+            # and set before writing.
+            if Path(images).suffix == '.mpg':
+                import numpy as np
+                import warnings
+
+                with warnings.catch_warnings():
+                    warnings.filterwarnings('ignore', category=UserWarning)
+                    frame = None
+                    duration = 0.0  # Duration of movie in seconds
+                    while True:
+                        result = clip.get_frame(duration)
+                        if frame is not None and np.all(frame == result):
+                            break
+
+                        duration += 0.1
+                        frame = result
+
+                    clip = clip.set_start(0)
+                    clip = clip.set_duration(duration)
+                    clip = clip.set_end(duration)
+                    clip.write_videofile(str(write_filename), **kwargs)
+
+            else:
+                clip.write_videofile(str(write_filename), **kwargs)
+
     else:
         clip = moviepy.video.io.ImageSequenceClip.ImageSequenceClip(images, fps=fps)
         clip.write_videofile(str(write_filename), **kwargs)

tests/utils/test_io_utils.py

@@ -275,5 +275,13 @@ def test_generate_movie():
             assert Path(result).name == write_filename
             assert np.isclose(Path(result).stat().st_size, 173189, 1000)
 
+            # Test converting MPEG to mp4
+            write_filename = 'movie3.mp4'
+            mpeg_file = sample_files.EXAMPLE_MPEG
+            result = act.utils.generate_movie(mpeg_file, write_filename=write_filename)
+            files = list(Path().glob(write_filename))
+            assert len(files) == 1
+            assert np.isclose(files[0].stat().st_size, 1625298, rtol=100, atol=100)
+
         finally:
             chdir(cwd)