--- a/dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp
+++ b/dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp
@@ -62,17 +62,17 @@ FFmpegRuntimeLinker::Init()
         sLinkStatus = LinkStatus_SUCCEEDED;
         return true;
       }
     }
   }
 
   FFMPEG_LOG("H264/AAC codecs unsupported without [");
   for (size_t i = 0; i < ArrayLength(sLibs); i++) {
-    FFMPEG_LOG("%s %s", i ? "," : "", sLibs[i]);
+    FFMPEG_LOG("%s %s", i ? "," : " ", sLibs[i]);
   }
   FFMPEG_LOG(" ]\n");
 
   sLinkStatus = LinkStatus_FAILED;
   return false;
 }
 
 /* static */ already_AddRefed<PlatformDecoderModule>