diff --git a/ox/file.py b/ox/file.py
index 7be0910..9c9955e 100644
--- a/ox/file.py
+++ b/ox/file.py
@@ -190,10 +190,11 @@ def avinfo(filename, cached=True):
                 p = subprocess.Popen([ffmpeg, '-i', filename], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                 stdout, stderr = p.communicate()
                 languages = [re.compile('\((.+?)\):').findall(l) for l in stderr.split('\n') if 'Stream' in l and 'Audio' in l]
-                for i, stream in enumerate(info['audio']):
-                    language = languages[i]
-                    if language and language[0] != 'und':
-                        stream['language'] = language[0]
+                if len(languages) == len(info['audio']):
+                    for i, stream in enumerate(info['audio']):
+                        language = languages[i]
+                        if language and language[0] != 'und':
+                            stream['language'] = language[0]
         return info
 
     return {'path': filename, 'size': 0}