Add log

lib/media/segment_utils.js

@@ -423,7 +423,7 @@ shaka.media.SegmentUtils = class {
           closedCaptions.set(stream, stream);
         }
       } catch (e) {
-        // Ignore errors.
+        shaka.log.debug('Error detecting CC streams', e);
       }
       captionParser.reset();
     }