Add content type information to encoded images and corresponding rtp extension header

webrtc/config.h

 /*
  *  Copyright (c) 2013 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 70 matching lines @@
   // http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
   static const char* kAbsSendTimeUri;
   static const int kAbsSendTimeDefaultId;
 
   // Header extension for coordination of video orientation, see url for
   // details:
   // http://www.etsi.org/deliver/etsi_ts/126100_126199/126114/12.07.00_60/ts_126114v120700p.pdf
   static const char* kVideoRotationUri;
   static const int kVideoRotationDefaultId;
 
+  // Header extension for video content type. E.g. default or screenshare.
+  static const char* kVideoContentTypeUri;

[tommi, 2017/04/10 10:59:18]

can this be declared inline as 
static const char kVideoContentTypeUri[] = "...";

Do we actually need the pointer to the string or is the string itself what we
need?

[ilnik, 2017/04/10 12:47:42]

I think it will be better if we leave it in the same way as in the other
extensions, and refactor them all later.

+  static const int kVideoContentTypeDefaultId;
+
   // Header extension for transport sequence number, see url for details:
   // http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions
   static const char* kTransportSequenceNumberUri;
   static const int kTransportSequenceNumberDefaultId;
 
   static const char* kPlayoutDelayUri;
   static const int kPlayoutDelayDefaultId;
 
   // Inclusive min and max IDs for one-byte header extensions, per RFC5285.
   static const int kMinId;
@@ skipping 127 matching lines @@
 
  private:
   // Access to the copy constructor is private to force use of the Copy()
   // method for those exceptional cases where we do use it.
   VideoEncoderConfig(const VideoEncoderConfig&);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CONFIG_H_