Replace streamio-ffmpeg library.

Replace the streamio-ffmpeg library with our own very thin FFmpeg wrapper.

app/logical/media_file/video.rb

@@ -3,14 +3,12 @@
 #
 # @see https://github.com/streamio/streamio-ffmpeg
 class MediaFile::Video < MediaFile
+  delegate :duration, :has_audio?, to: :video
+
   def dimensions
     [video.width, video.height]
   end
 
-  def duration
-    video.duration
-  end
-
   def preview(max_width, max_height)
     preview_frame.preview(max_width, max_height)
   end
@@ -19,20 +17,14 @@ class MediaFile::Video < MediaFile
     preview_frame.crop(max_width, max_height)
   end
 
-  def has_audio?
-    video.audio_channels.present?
-  end
-
   private
 
   def video
-    raise NotImplementedError, "can't process videos: ffmpeg or mkvmerge not installed" unless self.class.videos_enabled?
-
-    FFMPEG::Movie.new(file.path)
+    FFmpeg.new(file)
   end
 
   def preview_frame
-    FFmpeg.new(file).smart_video_preview
+    video.smart_video_preview
   end
 
   memoize :video, :preview_frame, :dimensions, :duration, :has_audio?