added mkv extension check before enzyme+exceptions

bazarr/embedded_subs_reader.py

@@ -1,17 +1,28 @@
 import enzyme
 import logging
+import os
+import subprocess
 
-from subprocess import check_output
 from utils import get_binary
 
+class MKVAndNoFFprobe(Exception):
+    pass
+
+class FFprobeError(Exception):
+    pass
+
 class EmbeddedSubsReader:
     def __init__(self):
         self.ffprobe = get_binary("ffprobe")
     
     def list_languages(self, file):
         if self.ffprobe:
-            return check_output([self.ffprobe, "-loglevel", "quiet", "-select_streams", "s", "-show_entries", "stream_tags=language", "-of", "csv=p=0", file], universal_newlines=True).strip().split("\n")
-        else:
+            try:
+                return subprocess.check_output([self.ffprobe, "-loglevel", "error", "-select_streams", "s", "-show_entries", "stream_tags=language", "-of", "csv=p=0", file], universal_newlines=True, stderr=subprocess.STDOUT).strip().split("\n")
+            except subprocess.CalledProcessError as e:
+                raise FFprobeError(e.output)
+        if os.path.splitext(file)[1] != '.mkv':
+            raise MKVAndNoFFprobe()
         with open(file, 'rb') as f:
             mkv = enzyme.MKV(f)
         return [subtitle_track.language for subtitle_track in mkv.subtitle_tracks]