Do basic parsing of RTCP headers in PcapFileReader to enable log filtering.

BUG=
R=mflodman@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1697004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4266 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/rtp_rtcp/source/rtp_utility.cc

@@ -49,8 +49,12 @@ namespace webrtc {
 namespace ModuleRTPUtility {
 
 enum {
+  kRtcpExpectedVersion = 2,
   kRtcpMinHeaderLength = 4,
-  kRtcpExpectedVersion = 2
+  kRtcpMinParseLength = 8,
+
+  kRtpExpectedVersion = 2,
+  kRtpMinParseLength = 12
 };
 
 /*
@@ -291,11 +295,39 @@ bool RTPHeaderParser::RTCP() const {
   return RTCP;
 }
 
+bool RTPHeaderParser::ParseRtcp(RTPHeader* header) const {
+  assert(header != NULL);
+
+  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 uint16_t len = (_ptrRTPDataBegin[2] << 8) + _ptrRTPDataBegin[3];
+  const uint8_t* ptr = &_ptrRTPDataBegin[4];
+
+  uint32_t SSRC = *ptr++ << 24;
+  SSRC += *ptr++ << 16;
+  SSRC += *ptr++ << 8;
+  SSRC += *ptr++;
+
+  header->payloadType  = PT;
+  header->ssrc         = SSRC;
+  header->headerLength = 4 + (len << 2);
+
+  return true;
+}
+
 bool RTPHeaderParser::Parse(RTPHeader& header,
                             RtpHeaderExtensionMap* ptrExtensionMap) const {
   const ptrdiff_t length = _ptrRTPDataEnd - _ptrRTPDataBegin;
-
-  if (length < 12) {
+  if (length < kRtpMinParseLength) {
     return false;
   }
 
@@ -325,7 +357,7 @@ bool RTPHeaderParser::Parse(RTPHeader& header,
   SSRC += *ptr++ << 8;
   SSRC += *ptr++;
 
-  if (V != 2) {
+  if (V != kRtpExpectedVersion) {
     return false;
   }
 

webrtc/modules/rtp_rtcp/source/rtp_utility.h

@@ -124,6 +124,7 @@ namespace ModuleRTPUtility
         ~RTPHeaderParser();
 
         bool RTCP() const;
+        bool ParseRtcp(RTPHeader* header) const;
         bool Parse(RTPHeader& parsedPacket,
                    RtpHeaderExtensionMap* ptrExtensionMap = NULL) const;
 

webrtc/modules/video_coding/main/test/pcap_file_reader.cc

@@ -114,10 +114,9 @@ class PcapFileReaderImpl : public RtpPacketSourceInterface {
     uint32_t stream_start_ms = 0;
     int32_t next_packet_pos = ftell(file_);
     for (;;) {
-      ++total_packet_count;
       TRY(fseek(file_, next_packet_pos, SEEK_SET));
       int result = ReadPacket(&next_packet_pos, stream_start_ms,
-                              total_packet_count);
+                              ++total_packet_count);
       if (result == kResultFail) {
         break;
       } else if (result == kResultSuccess && packets_.size() == 1) {
@@ -140,8 +139,9 @@ class PcapFileReaderImpl : public RtpPacketSourceInterface {
         mit != packets_by_ssrc_.end(); ++mit) {
       uint32_t ssrc = mit->first;
       const std::vector<uint32_t>& packet_numbers = mit->second;
-      printf("SSRC: %08x, %d packets\n", ssrc,
-             static_cast<int>(packet_numbers.size()));
+      uint8_t pt = packets_[packet_numbers[0]].rtp_header.payloadType;
+      printf("SSRC: %08x, %d packets, pt=%d\n", ssrc,
+             static_cast<int>(packet_numbers.size()), pt);
     }
 
     // TODO(solenberg): Better validation of identified SSRC streams.
@@ -187,14 +187,14 @@ class PcapFileReaderImpl : public RtpPacketSourceInterface {
  private:
   // A marker of an RTP packet within the file.
   struct RtpPacketMarker {
-    uint32_t packet_number;
+    uint32_t packet_number;   // One-based index (like in WireShark)
     uint32_t time_offset_ms;
     uint32_t source_ip;
     uint32_t dest_ip;
     uint16_t source_port;
     uint16_t dest_port;
     RTPHeader rtp_header;
-    int32_t pos_in_file;
+    int32_t pos_in_file;      // Byte offset of payload from start of file.
     uint32_t payload_length;
   };
 
@@ -270,6 +270,7 @@ class PcapFileReaderImpl : public RtpPacketSourceInterface {
     ModuleRTPUtility::RTPHeaderParser rtp_parser(read_buffer_,
                                                  marker.payload_length);
     if (rtp_parser.RTCP()) {
+      rtp_parser.ParseRtcp(&marker.rtp_header);
       packets_.push_back(marker);
     } else {
       if (!rtp_parser.Parse(marker.rtp_header, NULL)) {