Add read support of RtpStreamId/RepairedRtpStreamId header extensions.

webrtc/common_types.h

 /*
  *  Copyright (c) 2012 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 699 matching lines @@
   bool voiceActivity;
   uint8_t audioLevel;
 
   // For Coordination of Video Orientation. See
   // http://www.etsi.org/deliver/etsi_ts/126100_126199/126114/12.07.00_60/
   // ts_126114v120700p.pdf
   bool hasVideoRotation;
   VideoRotation videoRotation;
 
   PlayoutDelay playout_delay = {-1, -1};
+
+  // For identification of a stream when ssrc is not signaled. See
+  // https://tools.ietf.org/html/draft-ietf-avtext-rid-09
+  // TODO(danilchap): Update url from draft to release version.
+  size_t rid_size = 0;
+  char rid[16];

[pthatcher1, 2017/04/06 21:17:34]

The SDP level uses "rid=", but the header extensions are not actually called
"RIDs".    I think you'd be better off with "rtp_stream_id" and
"repaired_rtp_stream_id" here.  If that's too long, perhaps "stream_id and
"rsid" and "repaired_rsid".  

[danilchap, 2017/04/07 07:07:49]

Since structure type already have 'rtp' in it, I'll go for
stream_id/repaired_stream_id.

+  size_t repair_rid_size = 0;
+  char repair_rid[16];

[pthatcher1, 2017/04/06 21:17:34]

The header extension can be more than 16 chars, even though the WebRTC API only
allows WebRTC clients to be up to 16 chars.    They will usually be 1-2 chars,
I'm guessing.  Why don't we just using a std::string here?

[danilchap, 2017/04/07 07:07:49]

std::string will turn this and all dependent structures (RTPHeader,
WebRtcRTPHeader) from POD.
Which will break in some random places since this structures reset or copied
with memset/memcpy sometimes.

long-term would prefer to use std::string.

 };
 
 struct RTPHeader {
   RTPHeader();
 
   bool markerBit;
   uint8_t payloadType;
   uint16_t sequenceNumber;
   uint32_t timestamp;
   uint32_t ssrc;
@@ skipping 105 matching lines @@
 enum class RtcpMode { kOff, kCompound, kReducedSize };
 
 enum NetworkState {
   kNetworkUp,
   kNetworkDown,
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_TYPES_H_