From c412a9c177bf3000d814e295ff532537a04b64ca Mon Sep 17 00:00:00 2001
From: philipel <philipel@webrtc.org>
Date: Fri, 30 Dec 2022 13:15:35 +0100
Subject: [PATCH] Record packets starting from a zero offset in RtpDumpWriter.
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Bug: webrtc:14801
Change-Id: I5afb305003e3abde46829500a8b0eb48d95da2b3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/289960
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38982}
---
 test/BUILD.gn                    |  5 ++++-
 test/rtp_file_writer.cc          |  7 ++++++-
 test/rtp_file_writer_unittest.cc | 13 ++++++++++---
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/test/BUILD.gn b/test/BUILD.gn
index ab42ede40d..9842ba2733 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -231,7 +231,10 @@ rtc_library("rtp_test_utils") {
     "../rtc_base/synchronization:mutex",
     "../rtc_base/system:arch",
   ]
-  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
 }
 
 rtc_library("field_trial") {
diff --git a/test/rtp_file_writer.cc b/test/rtp_file_writer.cc
index c80b6387a7..22f664abc8 100644
--- a/test/rtp_file_writer.cc
+++ b/test/rtp_file_writer.cc
@@ -15,6 +15,7 @@
 
 #include <string>
 
+#include "absl/types/optional.h"
 #include "rtc_base/checks.h"
 
 namespace webrtc {
@@ -42,9 +43,12 @@ class RtpDumpWriter : public RtpFileWriter {
   RtpDumpWriter& operator=(const RtpDumpWriter&) = delete;
 
   bool WritePacket(const RtpPacket* packet) override {
+    if (!first_packet_time_) {
+      first_packet_time_ = packet->time_ms;
+    }
     uint16_t len = static_cast<uint16_t>(packet->length + kPacketHeaderSize);
     uint16_t plen = static_cast<uint16_t>(packet->original_length);
-    uint32_t offset = packet->time_ms;
+    uint32_t offset = packet->time_ms - *first_packet_time_;
     RTC_CHECK(WriteUint16(len));
     RTC_CHECK(WriteUint16(plen));
     RTC_CHECK(WriteUint32(offset));
@@ -88,6 +92,7 @@ class RtpDumpWriter : public RtpFileWriter {
   }
 
   FILE* file_;
+  absl::optional<uint32_t> first_packet_time_;
 };
 
 RtpFileWriter* RtpFileWriter::Create(FileFormat format,
diff --git a/test/rtp_file_writer_unittest.cc b/test/rtp_file_writer_unittest.cc
index a6281c7787..2396d7c346 100644
--- a/test/rtp_file_writer_unittest.cc
+++ b/test/rtp_file_writer_unittest.cc
@@ -29,13 +29,13 @@ class RtpFileWriterTest : public ::testing::Test {
         test::RtpFileWriter::Create(test::RtpFileWriter::kRtpDump, filename_));
   }
 
-  void WriteRtpPackets(int num_packets) {
+  void WriteRtpPackets(int num_packets, int time_ms_offset = 0) {
     ASSERT_TRUE(rtp_writer_.get() != NULL);
     test::RtpPacket packet;
     for (int i = 1; i <= num_packets; ++i) {
       packet.length = i;
       packet.original_length = i;
-      packet.time_ms = i;
+      packet.time_ms = i + time_ms_offset;
       memset(packet.data, i, packet.length);
       EXPECT_TRUE(rtp_writer_->WritePacket(&packet));
     }
@@ -55,7 +55,7 @@ class RtpFileWriterTest : public ::testing::Test {
       ++i;
       EXPECT_EQ(static_cast<size_t>(i), packet.length);
       EXPECT_EQ(static_cast<size_t>(i), packet.original_length);
-      EXPECT_EQ(static_cast<uint32_t>(i), packet.time_ms);
+      EXPECT_EQ(static_cast<uint32_t>(i - 1), packet.time_ms);
       for (int j = 0; j < i; ++j) {
         EXPECT_EQ(i, packet.data[j]);
       }
@@ -75,4 +75,11 @@ TEST_F(RtpFileWriterTest, WriteToRtpDump) {
   VerifyFileContents(10);
 }
 
+TEST_F(RtpFileWriterTest, WriteToRtpDumpWithOffset) {
+  Init("test_rtp_file_writer.rtp");
+  WriteRtpPackets(10, 100);
+  CloseOutputFile();
+  VerifyFileContents(10);
+}
+
 }  // namespace webrtc