use ffprobe in avinfo if installed

ox/file.py

@@ -9,6 +9,7 @@ import shutil
 import struct
 import subprocess
 import sqlite3
+from distutils.spawn import find_executable
 
 from .utils import json
 
@@ -154,6 +155,8 @@ def avinfo(filename, cached=True):
     if cached:
         return cache(filename, 'info')
     if os.path.getsize(filename):
+        if find_executable('ffprobe'):
+            return ffprobe(filename)
         ffmpeg2theora = cmd('ffmpeg2theora')
         p = subprocess.Popen([ffmpeg2theora], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         info, error = p.communicate()