fix aspect ratio

ox/file.py

@@ -275,9 +275,9 @@ def ffprobe(filename):
                 pass
                 # print s
         for v in info['video']:
+            k = 'display_aspect_ratio'
             if 'rotate' in info.get('metadata', {}) and int(info['metadata']['rotate']) in (-180, -90, 90, 180):
                 v['width'], v['height'] = v['height'], v['width']
-            k = 'display_aspect_ratio'
                 if k in v:
                     v[k] = ':'.join(reversed(v[k].split(':')))
             if k not in v and 'width' in v \