Add audio normalization function

Issue: Zulko#32
dspinellis · Jul 4, 2017 · 582ec7f · 582ec7f
1 parent 6ba12d0
commit 582ec7f
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Showing 5 changed files with 29 additions and 3 deletions.
diff --git a/docs/ref/audiofx.rst b/docs/ref/audiofx.rst
@@ -19,7 +19,8 @@ You can either import a single function like this: ::
 Or import everything: ::
     
     import moviepy.audio.fx.all as afx
-    newaudio = (audioclip.afx( vfx.volumex, 0.5)
+    newaudio = (audioclip.afx( vfx.normalize)
+                         .afx( vfx.volumex, 0.5)
                          .afx( vfx.audio_fadein, 1.0)
                          .afx( vfx.audio_fadeout, 1.0))
 
@@ -41,4 +42,5 @@ the module ``audio.fx`` is loaded as ``afx`` and you can use ``afx.volumex``, et
     audio_fadein
     audio_fadeout
     audio_loop
-    volumex
+    audio_normalize
+    volumex
diff --git a/docs/ref/audiofx/moviepy.audio.fx.all.audio_normalize.rst b/docs/ref/audiofx/moviepy.audio.fx.all.audio_normalize.rst
@@ -0,0 +1,6 @@
+moviepy.audio.fx.all.audio_normalize
+==================================
+
+.. currentmodule:: moviepy.audio.fx.all
+
+.. autofunction:: audio_normalize
diff --git a/moviepy/audio/fx/audio_normalize.py b/moviepy/audio/fx/audio_normalize.py
@@ -0,0 +1,9 @@
+from moviepy.decorators import audio_video_fx
+
+@audio_video_fx
+def audio_normalize(clip):
+    """ Return an audio (or video) clip whose volume is normalized
+        to 0db."""
+
+    mv = clip.max_volume()
+    return clip.volumex(1 / mv)
diff --git a/moviepy/editor.py b/moviepy/editor.py
@@ -53,6 +53,7 @@
 for method in [
           "afx.audio_fadein",
           "afx.audio_fadeout",
+          "afx.audio_normalize",
           "afx.volumex",
           "transfx.crossfadein",
           "transfx.crossfadeout",
@@ -75,6 +76,7 @@
 for method in ["afx.audio_fadein",
                "afx.audio_fadeout",
                "afx.audio_loop",
+               "afx.audio_normalize",
                "afx.volumex"
               ]:
 
@@ -111,4 +113,4 @@ def preview(self, *args, **kwargs):
         """ NOT AVAILABLE : clip.preview requires Pygame installed."""
         raise ImportError("clip.preview requires Pygame installed")
 
-AudioClip.preview = preview
+AudioClip.preview = preview
diff --git a/tests/test_fx.py b/tests/test_fx.py
@@ -8,6 +8,8 @@
 from moviepy.video.fx.crop import crop
 from moviepy.video.fx.fadein import fadein
 from moviepy.video.fx.fadeout import fadeout
+from moviepy.audio.fx.audio_normalize import audio_normalize
+from moviepy.audio.io.AudioFileClip import AudioFileClip
 from moviepy.video.io.VideoFileClip import VideoFileClip
 
 import download_media
@@ -67,6 +69,11 @@ def test_fadeout():
     clip1 = fadeout(clip, 1)
     clip1.write_videofile(os.path.join(TMP_DIR,"fadeout1.webm"))
 
+def test_normalize():
+    clip = AudioFileClip('media/crunching.mp3')
+    clip = audio_normalize(clip)
+    assert clip.max_volume() == 1
+
 
 if __name__ == '__main__':
    pytest.main()