gistfile1.txt

--- a/dom/media/AutoplayPolicy.cpp
+++ b/dom/media/AutoplayPolicy.cpp
@@ -119,7 +119,8 @@ static bool IsWindowAllowedToPlay(nsPIDOMWindowInner* aWindow) {
 static uint32_t DefaultAutoplayBehaviour() {
   int prefValue =
       Preferences::GetInt("media.autoplay.default", nsIAutoplay::ALLOWED);
-  if (prefValue < nsIAutoplay::ALLOWED || prefValue > nsIAutoplay::BLOCKED) {
+  if (prefValue < nsIAutoplay::ALLOWED || prefValue > nsIAutoplay::BLOCKED_ALL) {
     // Invalid pref values are just converted to BLOCKED.
     return nsIAutoplay::BLOCKED;
   }
@@ -127,8 +128,11 @@ static uint32_t DefaultAutoplayBehaviour() {
 }

 static bool IsMediaElementAllowedToPlay(const HTMLMediaElement& aElement) {
-  const bool isAllowedMuted =
-      Preferences::GetBool("media.autoplay.allow-muted", true);
+  const bool isAllowedMuted = DefaultAutoplayBehaviour() != nsIAutoplay::BLOCKED_ALL;
   if ((aElement.Volume() == 0.0 || aElement.Muted()) && isAllowedMuted) {
     AUTOPLAY_LOG("Allow muted media %p to autoplay.", &aElement);
     return true;
     
// Above lets setting media.autoplay.default   

bool nsContentUtils::IsSitePermDeny(nsIPrincipal* aPrincipal,
                                    const nsACString& aType) {
  return TestSitePerm(aPrincipal, aType, nsIPermissionManager::DENY_ACTION,
                      false);
}