1 files changed, 58 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_descriptor_authentication.cc b/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_descriptor_authentication.cc
new file mode 100644
index 0000000000..f4525f0db1
--- /dev/null
+++ b/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_descriptor_authentication.cc
@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/rtp_rtcp/source/rtp_descriptor_authentication.h"
+
+#include <cstdint>
+#include <vector>
+
+#include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor.h"
+#include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor_extension.h"
+#include "modules/rtp_rtcp/source/rtp_video_header.h"
+
+namespace webrtc {
+
+std::vector<uint8_t> RtpDescriptorAuthentication(
+    const RTPVideoHeader& rtp_video_header) {
+  if (!rtp_video_header.generic) {
+    return {};
+  }
+  const RTPVideoHeader::GenericDescriptorInfo& descriptor =
+      *rtp_video_header.generic;
+  // Default way of creating additional data for an encrypted frame.
+  if (descriptor.spatial_index < 0 || descriptor.temporal_index < 0 ||
+      descriptor.spatial_index >=
+          RtpGenericFrameDescriptor::kMaxSpatialLayers ||
+      descriptor.temporal_index >=
+          RtpGenericFrameDescriptor::kMaxTemporalLayers ||
+      descriptor.dependencies.size() >
+          RtpGenericFrameDescriptor::kMaxNumFrameDependencies) {
+    return {};
+  }
+  RtpGenericFrameDescriptor frame_descriptor;
+  frame_descriptor.SetFirstPacketInSubFrame(true);
+  frame_descriptor.SetLastPacketInSubFrame(false);
+  frame_descriptor.SetTemporalLayer(descriptor.temporal_index);
+  frame_descriptor.SetSpatialLayersBitmask(1 << descriptor.spatial_index);
+  frame_descriptor.SetFrameId(descriptor.frame_id & 0xFFFF);
+  for (int64_t dependency : descriptor.dependencies) {
+    frame_descriptor.AddFrameDependencyDiff(descriptor.frame_id - dependency);
+  }
+  if (descriptor.dependencies.empty()) {
+    frame_descriptor.SetResolution(rtp_video_header.width,
+                                   rtp_video_header.height);
+  }
+  std::vector<uint8_t> result(
+      RtpGenericFrameDescriptorExtension00::ValueSize(frame_descriptor));
+  RtpGenericFrameDescriptorExtension00::Write(result, frame_descriptor);
+  return result;
+}
+
+}  // namespace webrtc