Filter overlapping RTP header extensions.

talk/media/webrtc/webrtcmediaengine.cc

Index: talk/media/webrtc/webrtcmediaengine.cc
diff --git a/talk/media/webrtc/webrtcmediaengine.cc b/talk/media/webrtc/webrtcmediaengine.cc
index cf6a5cf2e59689fbaf877fcf7d69ab41eba78ef3..0f79edf4fbea631ff2fb28cd41e3118c541c09cc 100644
--- a/talk/media/webrtc/webrtcmediaengine.cc
+++ b/talk/media/webrtc/webrtcmediaengine.cc
@@ -68,4 +68,35 @@ MediaEngineInterface* WebRtcMediaEngineFactory::Create(
   return CreateWebRtcMediaEngine(adm, encoder_factory, decoder_factory);
 }
 
+static const std::map<std::string, int> CreateBweExtensionPriorities() {
+  std::map<std::string, int> extension_prios;
+  extension_prios[kRtpTransportSequenceNumberHeaderExtension] = 0;
+  extension_prios[kRtpAbsoluteSenderTimeHeaderExtension] = 1;
+  extension_prios[kRtpTimestampOffsetHeaderExtension] = 2;
+  return extension_prios;
+}
+const std::map<std::string, int> kBweExtensionPriorities =
+    CreateBweExtensionPriorities();

[pbos-webrtc, 2015/10/29 14:16:22]

Static initializer, not permitted. Can you make this a POD struct {const char*,
int} instead? Scanning through a map with 3 elements shouldn't be more effective
either way.

[stefan-webrtc, 2015/10/29 14:51:11]

Done.

+
+std::vector<RtpHeaderExtension> FilterOverlappingRtpExtensions(
+    const std::vector<RtpHeaderExtension>& extensions,
+    const std::map<std::string, int>& extension_prios) {
+  if (extensions.empty())
+    return std::vector<RtpHeaderExtension>();
+  std::vector<RtpHeaderExtension> filtered;
+  std::map<int, const RtpHeaderExtension*> sorted;
+  for (auto& extension : extensions) {
+    auto it = extension_prios.find(extension.uri);
+    if (it == extension_prios.end()) {
+      filtered.push_back(extension);
+      continue;
+    } else {
+      sorted[it->second] = &extension;
+    }
+  }
+  if (!sorted.empty())
+    filtered.push_back(*sorted.begin()->second);
+  return filtered;
+}
+
 }  // namespace cricket