Add RTX codecs for codecs only supported by external encoder.

webrtc/media/engine/webrtcvideoengine2.cc

 /*
  *  Copyright (c) 2014 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.
  */
 
@@ skipping 324 matching lines @@
 // duration hasn't been implemented.
 static const int kNackHistoryMs = 1000;
 
 static const int kDefaultQpMax = 56;
 
 static const int kDefaultRtcpReceiverReportSsrc = 1;
 
 // Down grade resolution at most 2 times for CPU reasons.
 static const int kMaxCpuDowngrades = 2;
 
+// Adds |codec| to |list|, and also adds an RTX codec if |codec|'s name is
+// recognized.
+// TODO(deadbeef): Should we add RTX codecs for external codecs whose names we
+// don't recognize?
+void AddCodecAndMaybeRtxCodec(const VideoCodec& codec,
+                              std::vector<VideoCodec>* codecs) {
+  codecs->push_back(codec);
+  int rtx_payload_type = 0;
+  if (CodecNamesEq(codec.name, kVp8CodecName)) {
+    rtx_payload_type = kDefaultRtxVp8PlType;
+  } else if (CodecNamesEq(codec.name, kVp9CodecName)) {
+    rtx_payload_type = kDefaultRtxVp9PlType;
+  } else if (CodecNamesEq(codec.name, kH264CodecName)) {
+    rtx_payload_type = kDefaultRtxH264PlType;
+  } else if (CodecNamesEq(codec.name, kRedCodecName)) {
+    rtx_payload_type = kDefaultRtxRedPlType;
+  } else {
+    return;
+  }
+  codecs->push_back(VideoCodec::CreateRtxCodec(rtx_payload_type, codec.id));
+}
+
 std::vector<VideoCodec> DefaultVideoCodecList() {
   std::vector<VideoCodec> codecs;
-  codecs.push_back(MakeVideoCodecWithDefaultFeedbackParams(kDefaultVp8PlType,
-                                                           kVp8CodecName));
-  codecs.push_back(
-      VideoCodec::CreateRtxCodec(kDefaultRtxVp8PlType, kDefaultVp8PlType));
+  AddCodecAndMaybeRtxCodec(
+      MakeVideoCodecWithDefaultFeedbackParams(kDefaultVp8PlType, kVp8CodecName),
+      &codecs);
   if (CodecIsInternallySupported(kVp9CodecName)) {
-    codecs.push_back(MakeVideoCodecWithDefaultFeedbackParams(kDefaultVp9PlType,
-                                                             kVp9CodecName));
-    codecs.push_back(
-        VideoCodec::CreateRtxCodec(kDefaultRtxVp9PlType, kDefaultVp9PlType));
+    AddCodecAndMaybeRtxCodec(MakeVideoCodecWithDefaultFeedbackParams(
+                                 kDefaultVp9PlType, kVp9CodecName),
+                             &codecs);
   }
   if (CodecIsInternallySupported(kH264CodecName)) {
     VideoCodec codec = MakeVideoCodecWithDefaultFeedbackParams(
         kDefaultH264PlType, kH264CodecName);
     // TODO(hta): Move all parameter generation for SDP into the codec
     // implementation, for all codecs and parameters.
     // TODO(hta): Move selection of profile-level-id to H.264 codec
     // implementation.
     // TODO(hta): Set FMTP parameters for all codecs of type H264.
     codec.SetParam(kH264FmtpProfileLevelId,
                    kH264ProfileLevelConstrainedBaseline);
     codec.SetParam(kH264FmtpLevelAsymmetryAllowed, "1");
     codec.SetParam(kH264FmtpPacketizationMode, "1");
-    codecs.push_back(codec);
-    codecs.push_back(
-        VideoCodec::CreateRtxCodec(kDefaultRtxH264PlType, kDefaultH264PlType));
+    AddCodecAndMaybeRtxCodec(codec, &codecs);
   }
-  codecs.push_back(VideoCodec(kDefaultRedPlType, kRedCodecName));
-  codecs.push_back(
-      VideoCodec::CreateRtxCodec(kDefaultRtxRedPlType, kDefaultRedPlType));
+  AddCodecAndMaybeRtxCodec(VideoCodec(kDefaultRedPlType, kRedCodecName),
+                           &codecs);
   codecs.push_back(VideoCodec(kDefaultUlpfecType, kUlpfecCodecName));
   return codecs;
 }
 
 std::vector<webrtc::VideoStream>
 WebRtcVideoChannel2::WebRtcVideoSendStream::CreateSimulcastVideoStreams(
     const VideoCodec& codec,
     const VideoOptions& options,
     int max_bitrate_bps,
     size_t num_streams) {
@@ skipping 229 matching lines @@
     if (i != codecs.size() - 1) {
       out << ", ";
     }
     // Don't add internally-supported codecs twice.
     if (CodecIsInternallySupported(codecs[i].name)) {
       continue;
     }
 
     // External video encoders are given payloads 120-127. This also means that
     // we only support up to 8 external payload types.
+    // TODO(deadbeef): mediasession.cc already has code to dynamically
+    // determine a payload type. We should be able to just leave the payload
+    // type empty and let mediasession determine it. However, currently RTX
+    // codecs are associated to codecs by payload type, meaning we DO need
+    // to allocate unique payload types here. So to make this change we would
+    // need to make RTX codecs associated by name instead.
     const int kExternalVideoPayloadTypeBase = 120;
     size_t payload_type = kExternalVideoPayloadTypeBase + i;
     RTC_DCHECK(payload_type < 128);
     VideoCodec codec(static_cast<int>(payload_type), codecs[i].name,
                      codecs[i].max_width, codecs[i].max_height,
                      codecs[i].max_fps);
 
     AddDefaultFeedbackParams(&codec);
-    supported_codecs.push_back(codec);
+    AddCodecAndMaybeRtxCodec(codec, &supported_codecs);
   }
   LOG(LS_INFO) << "Supported codecs (incl. external codecs): "
                << CodecVectorToString(supported_codecs);
   LOG(LS_INFO) << "Codecs supported by the external encoder factory: "
                << out.str();
   return supported_codecs;
 }
 
 WebRtcVideoChannel2::WebRtcVideoChannel2(
     webrtc::Call* call,
@@ skipping 1984 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             fec_settings.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket