--- a/media/libstagefright/binding/MP4Metadata.cpp
+++ b/media/libstagefright/binding/MP4Metadata.cpp
@@ -369,19 +369,19 @@ MP4Metadata::ReadTrackIndex(FallibleTArr
   if (mRustTestMode && ret && mRust) {
     mp4parse_byte_data data = {};
     bool rustRet = mRust->ReadTrackIndice(&data, aTrackID);
     MOZ_DIAGNOSTIC_ASSERT(rustRet);
     MOZ_DIAGNOSTIC_ASSERT(data.length == aDest.Length());
     for (uint32_t i = 0; i < data.length; i++) {
       MOZ_DIAGNOSTIC_ASSERT(data.indices[i].start_offset == aDest[i].start_offset);
       MOZ_DIAGNOSTIC_ASSERT(data.indices[i].end_offset == aDest[i].end_offset);
-      MOZ_DIAGNOSTIC_ASSERT(llabs(data.indices[i].start_composition - aDest[i].start_composition) <= 1);
-      MOZ_DIAGNOSTIC_ASSERT(llabs(data.indices[i].end_composition - aDest[i].end_composition) <= 1);
-      MOZ_DIAGNOSTIC_ASSERT(llabs(data.indices[i].start_decode - aDest[i].start_decode) <= 1);
+      MOZ_DIAGNOSTIC_ASSERT(llabs(int64_t(data.indices[i].start_composition - aDest[i].start_composition)) <= 1);
+      MOZ_DIAGNOSTIC_ASSERT(llabs(int64_t(data.indices[i].end_composition - aDest[i].end_composition)) <= 1);
+      MOZ_DIAGNOSTIC_ASSERT(llabs(int64_t(data.indices[i].start_decode - aDest[i].start_decode)) <= 1);
       MOZ_DIAGNOSTIC_ASSERT(data.indices[i].sync == aDest[i].sync);
     }
   }
 #endif
 
   return ret;
 }