Breaking out RTP header parsing from the RTP module.

This is the first step in order to move bandwidth estimation closer to the network. The goal is to have RTP header parsing and bandwidth estimation before voice and video engine, and have a joint estimate for audio and video.

Moving bandwidth estimation before the RTP module is also required for RTX.

TEST=vie_auto_test, voe_auto_test, trybots.
BUG=1811
R=andresp@webrtc.org, henrika@webrtc.org, mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1545004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4129 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/rtp_rtcp/interface/rtp_header_parser.h

@@ -0,0 +1,43 @@
+/*
+ *  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.
+ */
+#ifndef WEBRTC_MODULES_RTP_RTCP_INTERFACE_RTP_HEADER_PARSER_H_
+#define WEBRTC_MODULES_RTP_RTCP_INTERFACE_RTP_HEADER_PARSER_H_
+
+#include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp_defines.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+struct RTPHeader;
+
+class RtpHeaderParser {
+ public:
+  static RtpHeaderParser* Create();
+  virtual ~RtpHeaderParser() {}
+
+  // Returns true if the packet is an RTCP packet, false otherwise.
+  static bool IsRtcp(const uint8_t* packet, int length);
+
+  // Parses the packet and stores the parsed packet in |header|. Returns true on
+  // success, false otherwise.
+  // This method is thread-safe in the sense that it can parse multiple packets
+  // at once.
+  virtual bool Parse(const uint8_t* packet, int length,
+                     RTPHeader* header) const = 0;
+
+  // Registers an RTP header extension and binds it to |id|.
+  virtual bool RegisterRtpHeaderExtension(RTPExtensionType type,
+                                          uint8_t id) = 0;
+
+  // De-registers an RTP header extension.
+  virtual bool DeregisterRtpHeaderExtension(RTPExtensionType type) = 0;
+};
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_RTP_RTCP_INTERFACE_RTP_HEADER_PARSER_H_