diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index ea2435e0a..a74e73b0c 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -1301,7 +1301,7 @@ def dl(name, info):
                     downloaded = []
                     success = True
                     merger = FFmpegMergerPP(self, not self.params.get('keepvideo'))
-                    if not merger.available():
+                    if not merger.available:
                         postprocessors = []
                         self.report_warning('You have requested multiple '
                                             'formats but ffmpeg or avconv are not installed.'
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index 16babf6a5..e98fe9834 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -34,7 +34,7 @@ def __init__(self, downloader=None, deletetempfiles=False):
         self._determine_executables()
 
     def check_version(self):
-        if not self.available():
+        if not self.available:
             raise FFmpegPostProcessorError('ffmpeg or avconv not found. Please install one.')
 
         required_version = '10-0' if self._uses_avconv() else '1.0'
@@ -108,6 +108,7 @@ def _determine_executables(self):
                 self.probe_basename = p
                 break
 
+    @property
     def available(self):
         return self.basename is not None