--- a/dom/media/Benchmark.cpp
+++ b/dom/media/Benchmark.cpp
@@ -39,17 +39,18 @@ const char* VP9Benchmark::sBenchmarkFpsV
 bool VP9Benchmark::sHasRunTest = false;
 
 // static
 bool
 VP9Benchmark::IsVP9DecodeFast()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-#ifdef MOZ_WIDGET_ANDROID
+  // Disable VP9 estimizer on Mac, see bug 1400787.
+#if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_APPLEMEDIA)
   return false;
 #else
   bool hasPref = Preferences::HasUserValue(sBenchmarkFpsPref);
   uint32_t hadRecentUpdate = Preferences::GetUint(sBenchmarkFpsVersionCheck, 0U);
 
   if (!sHasRunTest && (!hasPref || hadRecentUpdate != sBenchmarkVersionID)) {
     sHasRunTest = true;