Bug 1874471: Disable payload-type matching for filters that know an s…

…src. r=mjf

Depends on D201766

Differential Revision: https://phabricator.services.mozilla.com/D201767

dom/media/webrtc/transportbridge/MediaPipelineFilter.cpp

@@ -85,20 +85,24 @@ bool MediaPipelineFilter::Filter(const webrtc::RTPHeader& header) {
   // Remote SSRC based filtering
   //
 
-  if (remote_ssrc_set_.count(header.ssrc)) {
+  if (!remote_ssrc_set_.empty()) {
+    if (remote_ssrc_set_.count(header.ssrc)) {
+      DEBUG_LOG(
+          ("MediaPipelineFilter SSRC: %u matched remote SSRC set."
+           " passing packet",
+           header.ssrc));
+      return true;
+    }
     DEBUG_LOG(
-        ("MediaPipelineFilter SSRC: %u matched remote SSRC set."
-         " passing packet",
-         header.ssrc));
-    return true;
+        ("MediaPipelineFilter SSRC: %u did not match any of %zu"
+         " remote SSRCS.",
+         header.ssrc, remote_ssrc_set_.size()));
+    return false;
   }
-  DEBUG_LOG(
-      ("MediaPipelineFilter SSRC: %u did not match any of %zu"
-       " remote SSRCS.",
-       header.ssrc, remote_ssrc_set_.size()));
 
   //
-  // PT, payload type, last ditch effort filtering
+  // PT, payload type, last ditch effort filtering. We only try this if we do
+  // not have any ssrcs configured (either by learning them, or negotiation).
   //
 
   if (receive_payload_type_set_.count(header.payloadType)) {

media/webrtc/signaling/gtest/mediapipeline_unittest.cpp

@@ -598,6 +598,15 @@ TEST_F(MediaPipelineFilterTest, TestSSRCFilter) {
   EXPECT_FALSE(Filter(filter, 556, 110));
 }
 
+TEST_F(MediaPipelineFilterTest, TestSSRCFilterOverridesPayloadTypeFilter) {
+  MediaPipelineFilter filter;
+  filter.AddRemoteSSRC(555);
+  filter.AddUniqueReceivePT(110);
+  // We have a configured ssrc; do not allow payload type matching.
+  EXPECT_FALSE(Filter(filter, 556, 110));
+  EXPECT_TRUE(Filter(filter, 555, 110));
+}
+
 #define SSRC(ssrc)                                                    \
   ((ssrc >> 24) & 0xFF), ((ssrc >> 16) & 0xFF), ((ssrc >> 8) & 0xFF), \
       (ssrc & 0xFF)
@@ -630,6 +639,11 @@ TEST_F(MediaPipelineFilterTest, TestPayloadTypeFilter) {
   filter.AddUniqueReceivePT(110);
   EXPECT_TRUE(Filter(filter, 555, 110));
   EXPECT_FALSE(Filter(filter, 556, 111));
+  // Matching based on unique payload type causes us to learn the ssrc.
+  EXPECT_TRUE(Filter(filter, 555, 98));
+  // Once we have learned an SSRC, do _not_ learn new ones based on payload
+  // type.
+  EXPECT_FALSE(Filter(filter, 557, 110));
 }
 
 TEST_F(MediaPipelineFilterTest, TestSSRCMovedWithMid) {