Bug 1928484 - add origin check to determine the HEVC support for CanP…

…layType() and IsTypeSupported(). r=jrmuizel,aosmond, a=dmeehan

When the pref 'media.wmf.hevc.enabled' is not equal to `1`, the HEVC is
only enabled through the media engine, which is used for EME playback
only.

Therefore, a quick workaround to prevent websites from using HEVC on
non-EME playback is to block HEVC on HTMLMediaElement::CanPlayType() and
MediaSource::IsTypeSupported().

This workaround should be removed after enaling HEVC for all playback in
the bug 1928536.

Differential Revision: https://phabricator.services.mozilla.com/D227572

dom/html/HTMLMediaElement.cpp

@@ -141,6 +141,11 @@
 #endif
 #include "xpcpublic.h"
 
+// TODO : remove this workaround after enabling HEVC by default in bug 1928536.
+#ifdef MOZ_WMF
+#  include "mozilla/EMEUtils.h"
+#endif
+
 mozilla::LazyLogModule gMediaElementLog("HTMLMediaElement");
 mozilla::LazyLogModule gMediaElementEventsLog("HTMLMediaElementEvents");
 
@@ -5020,7 +5025,24 @@ CanPlayStatus HTMLMediaElement::GetCanPlay(
 
 void HTMLMediaElement::CanPlayType(const nsAString& aType, nsAString& aResult) {
   DecoderDoctorDiagnostics diagnostics;
-  CanPlayStatus canPlay = GetCanPlay(aType, &diagnostics);
+  CanPlayStatus canPlay;
+#ifdef MOZ_WMF
+  // TODO : remove this workaround after enabling HEVC by default in bug
+  // 1928536.
+  bool isHEVC = false;
+  Maybe<MediaContainerType> containerType = MakeMediaContainerType(aType);
+  if (containerType) {
+    const auto& codecString = containerType->ExtendedType().Codecs().AsString();
+    isHEVC = StringBeginsWith(codecString, u"hev1"_ns) ||
+             StringBeginsWith(codecString, u"hvc1"_ns);
+  }
+  if (isHEVC && !IsHEVCAllowedByOrigin(GetOrigin(OwnerDoc()))) {
+    canPlay = CANPLAY_NO;
+  } else
+#endif
+  {
+    canPlay = GetCanPlay(aType, &diagnostics);
+  }
   diagnostics.StoreFormatDiagnostics(OwnerDoc(), aType, canPlay != CANPLAY_NO,
                                      __func__);
   switch (canPlay) {

dom/media/eme/EMEUtils.cpp

@@ -277,4 +277,29 @@ Maybe<nsCString> GetOrigin(const dom::Document* aDocument) {
   return Some(origin);
 }
 
+#ifdef MOZ_WMF
+bool IsHEVCAllowedByOrigin(const Maybe<nsCString>& aOrigin) {
+  if (StaticPrefs::media_wmf_hevc_enabled() == 1) {
+    return true;
+  }
+  if (!aOrigin) {
+    return false;
+  }
+  // This should be the same as the list in IsMFCDMAllowedByOrigin.
+  static nsTArray<nsCString> kAllowedOrigins({
+      "https://www.netflix.com"_ns,
+  });
+  for (const auto& allowedOrigin : kAllowedOrigins) {
+    if (FindInReadable(allowedOrigin, *aOrigin)) {
+      EME_LOG("IsHEVCAllowedByOrigin, origin (%s) is ALLOWED to use HEVC",
+              aOrigin->get());
+      return true;
+    }
+  }
+  EME_LOG("IsHEVCAllowedByOrigin, origin (%s) is NOT ALLOWED to use HEVC",
+          aOrigin->get());
+  return false;
+}
+#endif
+
 }  // namespace mozilla

dom/media/eme/EMEUtils.h

@@ -113,6 +113,11 @@ void DeprecationWarningLog(const dom::Document* aDocument,
 
 Maybe<nsCString> GetOrigin(const dom::Document* aDocument);
 
+#ifdef MOZ_WMF
+// TODO : remove this workaround after enabling HEVC by default in bug 1928536.
+bool IsHEVCAllowedByOrigin(const Maybe<nsCString>& aOrigin);
+#endif
+
 }  // namespace mozilla
 
 #endif  // EME_LOG_H_

dom/media/mediasource/MediaSource.cpp

@@ -40,6 +40,11 @@
 #  include "mozilla/java/HardwareCodecCapabilityUtilsWrappers.h"
 #endif
 
+// TODO : remove this workaround after enabling HEVC by default in bug 1928536.
+#ifdef MOZ_WMF
+#  include "mozilla/EMEUtils.h"
+#endif
+
 struct JSContext;
 class JSObject;
 
@@ -133,7 +138,8 @@ static void RecordTypeForTelemetry(const nsAString& aType,
 void MediaSource::IsTypeSupported(const nsAString& aType,
                                   DecoderDoctorDiagnostics* aDiagnostics,
                                   ErrorResult& aRv,
-                                  Maybe<bool> aShouldResistFingerprinting) {
+                                  Maybe<bool> aShouldResistFingerprinting,
+                                  Maybe<nsCString> aOrigin) {
   if (aType.IsEmpty()) {
     return aRv.ThrowTypeError("Empty type");
   }
@@ -157,6 +163,17 @@ void MediaSource::IsTypeSupported(const nsAString& aType,
     }
   }
 
+#ifdef MOZ_WMF
+  // TODO : remove this workaround after enabling HEVC by default in bug
+  // 1928536.
+  const auto& codecString = containerType->ExtendedType().Codecs().AsString();
+  const bool isHEVC = StringBeginsWith(codecString, u"hev1"_ns) ||
+                      StringBeginsWith(codecString, u"hvc1"_ns);
+  if (isHEVC && !IsHEVCAllowedByOrigin(aOrigin)) {
+    return aRv.ThrowNotSupportedError("Can't play type");
+  }
+#endif
+
   // Now we know that this media type could be played.
   // MediaSource imposes extra restrictions, and some prefs.
   // Avoid leaking information about the fact that it's pref-disabled,
@@ -452,7 +469,8 @@ bool MediaSource::IsTypeSupported(const GlobalObject& aOwner,
   IsTypeSupported(
       aType, &diagnostics, rv,
       doc ? Some(doc->ShouldResistFingerprinting(RFPTarget::MediaCapabilities))
-          : Nothing());
+          : Nothing(),
+      doc ? GetOrigin(doc) : Nothing());
   bool supported = !rv.Failed();
   RecordTypeForTelemetry(aType, window);
   diagnostics.StoreFormatDiagnostics(doc, aType, supported, __func__);

dom/media/mediasource/MediaSource.h

@@ -81,10 +81,13 @@ class MediaSource final : public DOMEventTargetHelper,
 
   static bool IsTypeSupported(const GlobalObject&, const nsAString& aType);
   // Throws on aRv if not supported.
+  // TODO : origin check should be removed after enabling HEVC by default in bug
+  // 1928536.
   static void IsTypeSupported(const nsAString& aType,
                               DecoderDoctorDiagnostics* aDiagnostics,
                               ErrorResult& aRv,
-                              Maybe<bool> aShouldResistFingerprinting);
+                              Maybe<bool> aShouldResistFingerprinting,
+                              Maybe<nsCString> aOrigin = Nothing());
 
   IMPL_EVENT_HANDLER(sourceopen);
   IMPL_EVENT_HANDLER(sourceended);