diff --git a/media/extractors/mp4/MPEG4Extractor.cpp b/media/extractors/mp4/MPEG4Extractor.cpp
index 99f32d5..dad36ec 100644
--- a/media/extractors/mp4/MPEG4Extractor.cpp
+++ b/media/extractors/mp4/MPEG4Extractor.cpp
@@ -321,8 +321,13 @@
         case FOURCC('h', 'e', 'v', '1'):
             return MEDIA_MIMETYPE_VIDEO_HEVC;
         default:
-            CHECK(!"should not be here.");
-            return NULL;
+            ALOGW("Unknown fourcc: %c%c%c%c",
+                   (fourcc >> 24) & 0xff,
+                   (fourcc >> 16) & 0xff,
+                   (fourcc >> 8) & 0xff,
+                   fourcc & 0xff
+                   );
+            return "application/octet-stream";
     }
 }