Delete helper to parse rtcp packet into rtp header

The only user of that function is only interested in the type of the
first rtcp message in the packet, which can be extracted in a simpler way

Bug: None
Change-Id: I96aeb8ed66099f94d506aa7d8d0d07378f6c952e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226543
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34515}
diff --git a/modules/rtp_rtcp/source/rtp_utility.cc b/modules/rtp_rtcp/source/rtp_utility.cc
index 9b68f0d..d76e198 100644
--- a/modules/rtp_rtcp/source/rtp_utility.cc
+++ b/modules/rtp_rtcp/source/rtp_utility.cc
@@ -130,33 +130,6 @@
   }
 }
 
-bool RtpHeaderParser::ParseRtcp(RTPHeader* header) const {
-  RTC_DCHECK(header);
-
-  const ptrdiff_t length = _ptrRTPDataEnd - _ptrRTPDataBegin;
-  if (length < kRtcpMinParseLength) {
-    return false;
-  }
-
-  const uint8_t V = _ptrRTPDataBegin[0] >> 6;
-  if (V != kRtcpExpectedVersion) {
-    return false;
-  }
-
-  const uint8_t PT = _ptrRTPDataBegin[1];
-  const size_t len = (_ptrRTPDataBegin[2] << 8) + _ptrRTPDataBegin[3];
-  const uint8_t* ptr = &_ptrRTPDataBegin[4];
-
-  uint32_t SSRC = ByteReader<uint32_t>::ReadBigEndian(ptr);
-  ptr += 4;
-
-  header->payloadType = PT;
-  header->ssrc = SSRC;
-  header->headerLength = 4 + (len << 2);
-
-  return true;
-}
-
 bool RtpHeaderParser::Parse(RTPHeader* header,
                             const RtpHeaderExtensionMap* ptrExtensionMap,
                             bool header_only) const {
diff --git a/modules/rtp_rtcp/source/rtp_utility.h b/modules/rtp_rtcp/source/rtp_utility.h
index cdfff40..20aac54 100644
--- a/modules/rtp_rtcp/source/rtp_utility.h
+++ b/modules/rtp_rtcp/source/rtp_utility.h
@@ -37,7 +37,6 @@
 
   ABSL_DEPRECATED("Use IsRtpPacket or IsRtcpPacket")
   bool RTCP() const;
-  bool ParseRtcp(RTPHeader* header) const;
   bool Parse(RTPHeader* parsedPacket,
              const RtpHeaderExtensionMap* ptrExtensionMap = nullptr,
              bool header_only = false) const;
diff --git a/test/rtp_file_reader.cc b/test/rtp_file_reader.cc
index a09d5a6..203cbdf 100644
--- a/test/rtp_file_reader.cc
+++ b/test/rtp_file_reader.cc
@@ -18,7 +18,6 @@
 #include <vector>
 
 #include "modules/rtp_rtcp/source/rtp_util.h"
-#include "modules/rtp_rtcp/source/rtp_utility.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/constructor_magic.h"
 #include "rtc_base/format_macros.h"
@@ -295,7 +294,7 @@
          mit != packets_by_ssrc_.end(); ++mit) {
       uint32_t ssrc = mit->first;
       const std::vector<uint32_t>& packet_indices = mit->second;
-      uint8_t pt = packets_[packet_indices[0]].rtp_header.payloadType;
+      int pt = packets_[packet_indices[0]].payload_type;
       printf("SSRC: %08x, %" RTC_PRIuS " packets, pt=%d\n", ssrc,
              packet_indices.size(), pt);
     }
@@ -358,7 +357,9 @@
     uint32_t dest_ip;
     uint16_t source_port;
     uint16_t dest_port;
-    RTPHeader rtp_header;
+    // Payload type of the RTP packet,
+    // or RTCP packet type of the first RTCP packet in a compound RTCP packet.
+    int payload_type;
     int32_t pos_in_file;  // Byte offset of payload from start of file.
     uint32_t payload_length;
   };
@@ -434,17 +435,13 @@
     }
     TRY_PCAP(Read(read_buffer_, marker.payload_length));
 
-    RtpUtility::RtpHeaderParser rtp_parser(read_buffer_, marker.payload_length);
-    if (IsRtcpPacket(rtc::MakeArrayView(read_buffer_, marker.payload_length))) {
-      rtp_parser.ParseRtcp(&marker.rtp_header);
+    rtc::ArrayView<const uint8_t> packet(read_buffer_, marker.payload_length);
+    if (IsRtcpPacket(packet)) {
+      marker.payload_type = packet[1];
       packets_.push_back(marker);
-    } else {
-      if (!rtp_parser.Parse(&marker.rtp_header, nullptr)) {
-        RTC_LOG(LS_INFO) << "Not recognized as RTP/RTCP";
-        return kResultSkip;
-      }
-
-      uint32_t ssrc = marker.rtp_header.ssrc;
+    } else if (IsRtpPacket(packet)) {
+      uint32_t ssrc = ParseRtpSsrc(packet);
+      marker.payload_type = ParseRtpPayloadType(packet);
       if (ssrc_filter.empty() || ssrc_filter.find(ssrc) != ssrc_filter.end()) {
         packets_by_ssrc_[ssrc].push_back(
             static_cast<uint32_t>(packets_.size()));
@@ -452,6 +449,9 @@
       } else {
         return kResultSkip;
       }
+    } else {
+      RTC_LOG(LS_INFO) << "Not recognized as RTP/RTCP";
+      return kResultSkip;
     }
 
     return kResultSuccess;