Add support for FEC-FR semantics in StreamParams.

webrtc/media/base/streamparams.cc

 /*
  *  Copyright (c) 2011 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 "webrtc/media/base/streamparams.h"
 
 #include <list>
 #include <sstream>
 
 namespace cricket {
 namespace {
 // NOTE: There is no check here for duplicate streams, so check before
 // adding.
 void AddStream(std::vector<StreamParams>* streams, const StreamParams& stream) {
   streams->push_back(stream);
 }
 }
 
 const char kFecSsrcGroupSemantics[] = "FEC";
+const char kFecFrSsrcGroupSemantics[] = "FEC-FR";
 const char kFidSsrcGroupSemantics[] = "FID";
 const char kSimSsrcGroupSemantics[] = "SIM";
 
 bool GetStream(const StreamParamsVec& streams,
                const StreamSelector& selector,
                StreamParams* stream_out) {
   const StreamParams* found = GetStream(streams, selector);
   if (found && stream_out)
     *stream_out = *found;
   return found != nullptr;
@@ skipping 157 matching lines @@
       return true;
     }
   }
   return false;
 }
 
 bool IsOneSsrcStream(const StreamParams& sp) {
   if (sp.ssrcs.size() == 1 && sp.ssrc_groups.empty()) {
     return true;
   }
+  const SsrcGroup* fid_group = sp.get_ssrc_group(kFidSsrcGroupSemantics);
+  const SsrcGroup* fecfr_group = sp.get_ssrc_group(kFecFrSsrcGroupSemantics);
   if (sp.ssrcs.size() == 2) {
-    const SsrcGroup* fid_group = sp.get_ssrc_group(kFidSsrcGroupSemantics);
-    if (fid_group != NULL) {
-      return (sp.ssrcs == fid_group->ssrcs);
+    if (fid_group != nullptr && sp.ssrcs == fid_group->ssrcs) {
+      return true;
+    }
+    if (fecfr_group != nullptr && sp.ssrcs == fecfr_group->ssrcs) {
+      return true;
+    }
+  }
+  if (sp.ssrcs.size() == 3) {
+    if (fid_group == nullptr || fecfr_group == nullptr) {
+      return false;
+    }
+    if (sp.ssrcs[0] != fid_group->ssrcs[0] ||
+        sp.ssrcs[0] != fecfr_group->ssrcs[0]) {
+      return false;
+    }
+    // We do not check for FlexFEC over RTX,
+    // as this combination is not supported.
+    if (sp.ssrcs[1] == fid_group->ssrcs[1] &&
+        sp.ssrcs[2] == fecfr_group->ssrcs[1]) {
+      return true;
+    }
+    if (sp.ssrcs[1] == fecfr_group->ssrcs[1] &&
+        sp.ssrcs[2] == fid_group->ssrcs[1]) {
+      return true;
     }
   }
   return false;
 }
 
 static void RemoveFirst(std::list<uint32_t>* ssrcs, uint32_t value) {
   std::list<uint32_t>::iterator it =
       std::find(ssrcs->begin(), ssrcs->end(), value);
   if (it != ssrcs->end()) {
     ssrcs->erase(it);
@@ skipping 18 matching lines @@
         group.ssrcs.size() != 2) {
       continue;
     }
     RemoveFirst(&sp_ssrcs, group.ssrcs[1]);
   }
   // If there's SSRCs left that we don't know how to handle, we bail out.
   return sp_ssrcs.size() == 0;
 }
 
 }  // namespace cricket