media_stream: fix null pointer dereference

Change-Id: I42eeb5c88f6f042c8057780fde65cac40f59cb8e

src/media/media_stream.h

@@ -21,6 +21,7 @@
 #pragma once
 
 #include "libav_deps.h"
+#include "logger.h"
 #include "rational.h"
 #include "audio/audiobuffer.h"
 
@@ -90,6 +91,7 @@ struct MediaStream {
         : name(streamName)
         , firstTimestamp(startTimestamp)
     {
+        if (c) {
             timeBase = c->time_base;
             switch (c->codec_type) {
             case AVMEDIA_TYPE_VIDEO:
@@ -110,6 +112,9 @@ struct MediaStream {
             default:
                 break;
             }
+        } else {
+            JAMI_WARN() << "Trying to get stream info from null codec context";
+        }
     }
 
     MediaStream(const MediaStream& other) = default;