DOC Brain.save_movie(): note on FFmpeg

Author: christianbrodbeck

surfer/viz.py

@@ -2115,6 +2115,12 @@ def save_movie(self, fname, time_dilation=4., tmin=None, tmax=None,
             default 'quadratic').
         codec : str
             Codec to use with ffmpeg (default 'mpeg4').
+
+        Notes
+        -----
+        This method requires FFmpeg to be installed in the system PATH. FFmpeg
+        is free and can be obtained from `here
+        <http://ffmpeg.org/download.html>`_.
         """
         if not has_ffmpeg():
             err = ("FFmpeg is needed for saving movies and was not found in "