Add support for visualizing event logs without normalizing time.

Bug: webrtc:9299
Change-Id: Icdc4cba14f143cedb7c35347dd9711ab13f975d8
Reviewed-on: https://webrtc-review.googlesource.com/77820
Commit-Queue: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23392}
diff --git a/rtc_tools/event_log_visualizer/analyzer.cc b/rtc_tools/event_log_visualizer/analyzer.cc
index 76ac88a..71707a9 100644
--- a/rtc_tools/event_log_visualizer/analyzer.cc
+++ b/rtc_tools/event_log_visualizer/analyzer.cc
@@ -229,15 +229,14 @@
 // For each element in data_view, use |f()| to extract a y-coordinate and
 // store the result in a TimeSeries.
 template <typename DataType, typename IterableType>
-void ProcessPoints(rtc::FunctionView<rtc::Optional<float>(const DataType&)> f,
+void ProcessPoints(rtc::FunctionView<float(const DataType&)> fx,
+                   rtc::FunctionView<rtc::Optional<float>(const DataType&)> fy,
                    const IterableType& data_view,
-                   int64_t begin_time,
                    TimeSeries* result) {
   for (size_t i = 0; i < data_view.size(); i++) {
     const DataType& elem = data_view[i];
-    float x = static_cast<float>(elem.log_time_us() - begin_time) /
-              kNumMicrosecsPerSec;
-    rtc::Optional<float> y = f(elem);
+    float x = fx(elem);
+    rtc::Optional<float> y = fy(elem);
     if (y)
       result->points.emplace_back(x, *y);
   }
@@ -248,55 +247,33 @@
 // will be the time of the second element in the pair.
 template <typename DataType, typename ResultType, typename IterableType>
 void ProcessPairs(
+    rtc::FunctionView<float(const DataType&)> fx,
     rtc::FunctionView<rtc::Optional<ResultType>(const DataType&,
-                                                const DataType&)> f,
+                                                const DataType&)> fy,
     const IterableType& data,
-    int64_t begin_time,
     TimeSeries* result) {
   for (size_t i = 1; i < data.size(); i++) {
-    float x = static_cast<float>(data[i].log_time_us() - begin_time) /
-              kNumMicrosecsPerSec;
-    rtc::Optional<ResultType> y = f(data[i - 1], data[i]);
+    float x = fx(data[i]);
+    rtc::Optional<ResultType> y = fy(data[i - 1], data[i]);
     if (y)
       result->points.emplace_back(x, static_cast<float>(*y));
   }
 }
 
-// For each element in data, use |f()| to extract a y-coordinate and
-// store the result in a TimeSeries.
-template <typename DataType, typename ResultType, typename IterableType>
-void AccumulatePoints(
-    rtc::FunctionView<rtc::Optional<ResultType>(const DataType&)> f,
-    const IterableType& data,
-    int64_t begin_time,
-    TimeSeries* result) {
-  ResultType sum = 0;
-  for (size_t i = 0; i < data.size(); i++) {
-    float x = static_cast<float>(data[i].log_time_us() - begin_time) /
-              kNumMicrosecsPerSec;
-    rtc::Optional<ResultType> y = f(data[i]);
-    if (y) {
-      sum += *y;
-      result->points.emplace_back(x, static_cast<float>(sum));
-    }
-  }
-}
-
 // For each pair of adjacent elements in |data|, use |f()| to extract a
 // y-coordinate and store the result in a TimeSeries. Note that the x-coordinate
 // will be the time of the second element in the pair.
 template <typename DataType, typename ResultType, typename IterableType>
 void AccumulatePairs(
+    rtc::FunctionView<float(const DataType&)> fx,
     rtc::FunctionView<rtc::Optional<ResultType>(const DataType&,
-                                                const DataType&)> f,
+                                                const DataType&)> fy,
     const IterableType& data,
-    int64_t begin_time,
     TimeSeries* result) {
   ResultType sum = 0;
   for (size_t i = 1; i < data.size(); i++) {
-    float x = static_cast<float>(data[i].log_time_us() - begin_time) /
-              kNumMicrosecsPerSec;
-    rtc::Optional<ResultType> y = f(data[i - 1], data[i]);
+    float x = fx(data[i]);
+    rtc::Optional<ResultType> y = fy(data[i - 1], data[i]);
     if (y)
       sum += *y;
     result->points.emplace_back(x, static_cast<float>(sum));
@@ -309,7 +286,8 @@
 // during the preceeding |window_duration_us| microseconds.
 template <typename DataType, typename ResultType, typename IterableType>
 void MovingAverage(
-    rtc::FunctionView<rtc::Optional<ResultType>(const DataType&)> f,
+    rtc::FunctionView<float(int64_t)> fx,
+    rtc::FunctionView<rtc::Optional<ResultType>(const DataType&)> fy,
     const IterableType& data_view,
     int64_t begin_time,
     int64_t end_time,
@@ -323,7 +301,7 @@
   for (int64_t t = begin_time; t < end_time + step; t += step) {
     while (window_index_end < data_view.size() &&
            data_view[window_index_end].log_time_us() < t) {
-      rtc::Optional<ResultType> value = f(data_view[window_index_end]);
+      rtc::Optional<ResultType> value = fy(data_view[window_index_end]);
       if (value)
         sum_in_window += *value;
       ++window_index_end;
@@ -331,14 +309,14 @@
     while (window_index_begin < data_view.size() &&
            data_view[window_index_begin].log_time_us() <
                t - window_duration_us) {
-      rtc::Optional<ResultType> value = f(data_view[window_index_begin]);
+      rtc::Optional<ResultType> value = fy(data_view[window_index_begin]);
       if (value)
         sum_in_window -= *value;
       ++window_index_begin;
     }
     float window_duration_s =
         static_cast<float>(window_duration_us) / kNumMicrosecsPerSec;
-    float x = static_cast<float>(t - begin_time) / kNumMicrosecsPerSec;
+    float x = fx(t);
     float y = sum_in_window / window_duration_s;
     result->points.emplace_back(x, y);
   }
@@ -466,15 +444,19 @@
 
 }  // namespace
 
-EventLogAnalyzer::EventLogAnalyzer(const ParsedRtcEventLogNew& log)
-    : parsed_log_(log), window_duration_(250000), step_(10000) {
+EventLogAnalyzer::EventLogAnalyzer(const ParsedRtcEventLogNew& log,
+                                   bool normalize_time)
+    : parsed_log_(log),
+      window_duration_(250000),
+      step_(10000),
+      normalize_time_(normalize_time) {
   begin_time_ = parsed_log_.first_timestamp();
   end_time_ = parsed_log_.last_timestamp();
   if (end_time_ < begin_time_) {
     RTC_LOG(LS_WARNING) << "No useful events in the log.";
     begin_time_ = end_time_ = 0;
   }
-  call_duration_s_ = ToCallTime(end_time_);
+  call_duration_s_ = ToCallTimeSec(end_time_);
 
   const auto& log_start_events = parsed_log_.start_log_events();
   const auto& log_end_events = parsed_log_.stop_log_events();
@@ -532,8 +514,16 @@
   bool bitrate_updated_;
 };
 
-float EventLogAnalyzer::ToCallTime(int64_t timestamp) const {
-  return static_cast<float>(timestamp - begin_time_) / kNumMicrosecsPerSec;
+int64_t EventLogAnalyzer::ToCallTimeUs(int64_t timestamp) const {
+  int64_t begin_time = 0;
+  if (normalize_time_) {
+    begin_time = begin_time_;
+  }
+  return timestamp - begin_time;
+}
+
+float EventLogAnalyzer::ToCallTimeSec(int64_t timestamp) const {
+  return static_cast<float>(ToCallTimeUs(timestamp)) / kNumMicrosecsPerSec;
 }
 
 void EventLogAnalyzer::CreatePacketGraph(PacketDirection direction,
@@ -549,12 +539,16 @@
     auto GetPacketSize = [](const LoggedRtpPacket& packet) {
       return rtc::Optional<float>(packet.total_length);
     };
-    ProcessPoints<LoggedRtpPacket>(GetPacketSize, stream.packet_view,
-                                   begin_time_, &time_series);
+    auto ToCallTime = [this](const LoggedRtpPacket& packet) {
+      return this->ToCallTimeSec(packet.log_time_us());
+    };
+    ProcessPoints<LoggedRtpPacket>(ToCallTime, GetPacketSize,
+                                   stream.packet_view, &time_series);
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Packet size (bytes)", kBottomMargin,
                           kTopMargin);
   plot->SetTitle(GetDirectionAsString(direction) + " RTP packets");
@@ -567,7 +561,7 @@
     const std::string& label) {
   TimeSeries time_series(label, LineStyle::kStep);
   for (size_t i = 0; i < packets.size(); i++) {
-    float x = ToCallTime(packets[i].log_time_us());
+    float x = ToCallTimeSec(packets[i].log_time_us());
     time_series.points.emplace_back(x, i + 1);
   }
   plot->AppendTimeSeries(std::move(time_series));
@@ -592,7 +586,8 @@
         plot, parsed_log_.outgoing_rtcp_packets(), label);
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Received Packets", kBottomMargin, kTopMargin);
   plot->SetTitle(std::string("Accumulated ") + GetDirectionAsString(direction) +
                  " RTP/RTCP packets");
@@ -607,7 +602,7 @@
     rtc::Optional<int64_t> last_playout_ms;
     TimeSeries time_series(SsrcToString(ssrc), LineStyle::kBar);
     for (const auto& playout_event : playout_stream.second) {
-      float x = ToCallTime(playout_event.log_time_us());
+      float x = ToCallTimeSec(playout_event.log_time_us());
       int64_t playout_time_ms = playout_event.log_time_ms();
       // If there were no previous playouts, place the point on the x-axis.
       float y = playout_time_ms - last_playout_ms.value_or(playout_time_ms);
@@ -617,7 +612,8 @@
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Time since last playout (ms)", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Audio playout");
@@ -633,7 +629,7 @@
                            LineStyle::kLine);
     for (auto& packet : stream.packet_view) {
       if (packet.header.extension.hasAudioLevel) {
-        float x = ToCallTime(packet.log_time_us());
+        float x = ToCallTimeSec(packet.log_time_us());
         // The audio level is stored in -dBov (so e.g. -10 dBov is stored as 10)
         // Here we convert it to dBov.
         float y = static_cast<float>(-packet.header.extension.audioLevel);
@@ -643,7 +639,8 @@
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetYAxis(-127, 0, "Audio level (dBov)", kBottomMargin,
                  kTopMargin);
   plot->SetTitle(GetDirectionAsString(direction) + " audio level");
@@ -666,13 +663,17 @@
                              old_packet.rtp.header.sequenceNumber, 1ul << 16);
       return diff;
     };
-    ProcessPairs<LoggedRtpPacketIncoming, float>(GetSequenceNumberDiff,
-                                                 stream.incoming_packets,
-                                                 begin_time_, &time_series);
+    auto ToCallTime = [this](const LoggedRtpPacketIncoming& packet) {
+      return this->ToCallTimeSec(packet.log_time_us());
+    };
+    ProcessPairs<LoggedRtpPacketIncoming, float>(
+        ToCallTime, GetSequenceNumberDiff, stream.incoming_packets,
+        &time_series);
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Difference since last packet", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Sequence number");
@@ -718,7 +719,7 @@
             std::max(highest_prior_seq_number, sequence_number);
         ++window_index_begin;
       }
-      float x = ToCallTime(t);
+      float x = ToCallTimeSec(t);
       uint64_t expected_packets = highest_seq_number - highest_prior_seq_number;
       if (expected_packets > 0) {
         int64_t received_packets = window_index_end - window_index_begin;
@@ -730,7 +731,8 @@
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Estimated loss rate (%)", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Estimated incoming loss rate");
@@ -749,21 +751,25 @@
     TimeSeries capture_time_data(
         GetStreamName(kIncomingPacket, stream.ssrc) + " capture-time",
         LineStyle::kBar);
-    ProcessPairs<LoggedRtpPacket, double>(NetworkDelayDiff_CaptureTime,
-                                          stream.packet_view, begin_time_,
-                                          &capture_time_data);
+    auto ToCallTime = [this](const LoggedRtpPacket& packet) {
+      return this->ToCallTimeSec(packet.log_time_us());
+    };
+    ProcessPairs<LoggedRtpPacket, double>(
+        ToCallTime, NetworkDelayDiff_CaptureTime, stream.packet_view,
+        &capture_time_data);
     plot->AppendTimeSeries(std::move(capture_time_data));
 
     TimeSeries send_time_data(
         GetStreamName(kIncomingPacket, stream.ssrc) + " abs-send-time",
         LineStyle::kBar);
-    ProcessPairs<LoggedRtpPacket, double>(NetworkDelayDiff_AbsSendTime,
-                                          stream.packet_view, begin_time_,
-                                          &send_time_data);
+    ProcessPairs<LoggedRtpPacket, double>(ToCallTime,
+                                          NetworkDelayDiff_AbsSendTime,
+                                          stream.packet_view, &send_time_data);
     plot->AppendTimeSeries(std::move(send_time_data));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Latency change (ms)", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Network latency difference between consecutive packets");
@@ -782,21 +788,25 @@
     TimeSeries capture_time_data(
         GetStreamName(kIncomingPacket, stream.ssrc) + " capture-time",
         LineStyle::kLine);
-    AccumulatePairs<LoggedRtpPacket, double>(NetworkDelayDiff_CaptureTime,
-                                             stream.packet_view, begin_time_,
-                                             &capture_time_data);
+    auto ToCallTime = [this](const LoggedRtpPacket& packet) {
+      return this->ToCallTimeSec(packet.log_time_us());
+    };
+    AccumulatePairs<LoggedRtpPacket, double>(
+        ToCallTime, NetworkDelayDiff_CaptureTime, stream.packet_view,
+        &capture_time_data);
     plot->AppendTimeSeries(std::move(capture_time_data));
 
     TimeSeries send_time_data(
         GetStreamName(kIncomingPacket, stream.ssrc) + " abs-send-time",
         LineStyle::kLine);
-    AccumulatePairs<LoggedRtpPacket, double>(NetworkDelayDiff_AbsSendTime,
-                                             stream.packet_view, begin_time_,
-                                             &send_time_data);
+    AccumulatePairs<LoggedRtpPacket, double>(
+        ToCallTime, NetworkDelayDiff_AbsSendTime, stream.packet_view,
+        &send_time_data);
     plot->AppendTimeSeries(std::move(send_time_data));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Latency change (ms)", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Network latency (relative to first packet)");
@@ -807,13 +817,14 @@
   TimeSeries time_series("Fraction lost", LineStyle::kLine,
                          PointStyle::kHighlight);
   for (auto& bwe_update : parsed_log_.bwe_loss_updates()) {
-    float x = ToCallTime(bwe_update.log_time_us());
+    float x = ToCallTimeSec(bwe_update.log_time_us());
     float y = static_cast<float>(bwe_update.fraction_lost) / 255 * 100;
     time_series.points.emplace_back(x, y);
   }
 
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Percent lost packets", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Reported packet loss");
@@ -848,7 +859,7 @@
     }
     float window_duration_in_seconds =
         static_cast<float>(window_duration_) / kNumMicrosecsPerSec;
-    float x = ToCallTime(time);
+    float x = ToCallTimeSec(time);
     float y = bytes_in_window * 8 / window_duration_in_seconds / 1000;
     bitrate_series.points.emplace_back(x, y);
   }
@@ -857,13 +868,14 @@
   // Overlay the outgoing REMB over incoming bitrate.
   TimeSeries remb_series("Remb", LineStyle::kStep);
   for (const auto& rtcp : parsed_log_.rembs(kOutgoingPacket)) {
-    float x = ToCallTime(rtcp.log_time_us());
+    float x = ToCallTimeSec(rtcp.log_time_us());
     float y = static_cast<float>(rtcp.remb.bitrate_bps()) / 1000;
     remb_series.points.emplace_back(x, y);
   }
   plot->AppendTimeSeriesIfNotEmpty(std::move(remb_series));
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   plot->SetTitle("Incoming RTP bitrate");
 }
@@ -899,7 +911,7 @@
     }
     float window_duration_in_seconds =
         static_cast<float>(window_duration_) / kNumMicrosecsPerSec;
-    float x = ToCallTime(time);
+    float x = ToCallTimeSec(time);
     float y = bytes_in_window * 8 / window_duration_in_seconds / 1000;
     bitrate_series.points.emplace_back(x, y);
   }
@@ -908,7 +920,7 @@
   // Overlay the send-side bandwidth estimate over the outgoing bitrate.
   TimeSeries loss_series("Loss-based estimate", LineStyle::kStep);
   for (auto& loss_update : parsed_log_.bwe_loss_updates()) {
-    float x = ToCallTime(loss_update.log_time_us());
+    float x = ToCallTimeSec(loss_update.log_time_us());
     float y = static_cast<float>(loss_update.bitrate_bps) / 1000;
     loss_series.points.emplace_back(x, y);
   }
@@ -926,7 +938,7 @@
   BandwidthUsage last_detector_state = BandwidthUsage::kBwNormal;
 
   for (auto& delay_update : parsed_log_.bwe_delay_updates()) {
-    float x = ToCallTime(delay_update.log_time_us());
+    float x = ToCallTimeSec(delay_update.log_time_us());
     float y = static_cast<float>(delay_update.bitrate_bps) / 1000;
 
     if (last_detector_state != delay_update.detector_state) {
@@ -958,7 +970,7 @@
   TimeSeries created_series("Probe cluster created.", LineStyle::kNone,
                             PointStyle::kHighlight);
   for (auto& cluster : parsed_log_.bwe_probe_cluster_created_events()) {
-    float x = ToCallTime(cluster.log_time_us());
+    float x = ToCallTimeSec(cluster.log_time_us());
     float y = static_cast<float>(cluster.bitrate_bps) / 1000;
     created_series.points.emplace_back(x, y);
   }
@@ -967,7 +979,7 @@
                            PointStyle::kHighlight);
   for (auto& result : parsed_log_.bwe_probe_result_events()) {
     if (result.bitrate_bps) {
-      float x = ToCallTime(result.log_time_us());
+      float x = ToCallTimeSec(result.log_time_us());
       float y = static_cast<float>(*result.bitrate_bps) / 1000;
       result_series.points.emplace_back(x, y);
     }
@@ -977,20 +989,20 @@
   bool previously_in_alr = false;
   int64_t alr_start = 0;
   for (auto& alr : parsed_log_.alr_state_events()) {
-    float y = ToCallTime(alr.log_time_us());
+    float y = ToCallTimeSec(alr.log_time_us());
     if (!previously_in_alr && alr.in_alr) {
       alr_start = alr.log_time_us();
       previously_in_alr = true;
     } else if (previously_in_alr && !alr.in_alr) {
-      float x = ToCallTime(alr_start);
+      float x = ToCallTimeSec(alr_start);
       alr_state.intervals.emplace_back(x, y);
       previously_in_alr = false;
     }
   }
 
   if (previously_in_alr) {
-    float x = ToCallTime(alr_start);
-    float y = ToCallTime(end_time_);
+    float x = ToCallTimeSec(alr_start);
+    float y = ToCallTimeSec(end_time_);
     alr_state.intervals.emplace_back(x, y);
   }
 
@@ -1011,13 +1023,14 @@
   // Overlay the incoming REMB over the outgoing bitrate.
   TimeSeries remb_series("Remb", LineStyle::kStep);
   for (const auto& rtcp : parsed_log_.rembs(kIncomingPacket)) {
-    float x = ToCallTime(rtcp.log_time_us());
+    float x = ToCallTimeSec(rtcp.log_time_us());
     float y = static_cast<float>(rtcp.remb.bitrate_bps()) / 1000;
     remb_series.points.emplace_back(x, y);
   }
   plot->AppendTimeSeriesIfNotEmpty(std::move(remb_series));
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   plot->SetTitle("Outgoing RTP bitrate");
 }
@@ -1036,13 +1049,17 @@
     auto GetPacketSizeKilobits = [](const LoggedRtpPacket& packet) {
       return packet.total_length * 8.0 / 1000.0;
     };
+    auto ToCallTime = [this](int64_t time) {
+      return this->ToCallTimeSec(time);
+    };
     MovingAverage<LoggedRtpPacket, double>(
-        GetPacketSizeKilobits, stream.packet_view, begin_time_, end_time_,
-        window_duration_, step_, &time_series);
+        ToCallTime, GetPacketSizeKilobits, stream.packet_view, begin_time_,
+        end_time_, window_duration_, step_, &time_series);
     plot->AppendTimeSeries(std::move(time_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   plot->SetTitle(GetDirectionAsString(direction) + " bitrate per stream");
 }
@@ -1133,7 +1150,7 @@
           acked_bitrate.Update(packet.payload_size, packet.arrival_time_ms);
         bitrate_bps = acked_bitrate.Rate(feedback.back().arrival_time_ms);
       }
-      float x = ToCallTime(clock.TimeInMicroseconds());
+      float x = ToCallTimeSec(clock.TimeInMicroseconds());
       float y = bitrate_bps.value_or(0) / 1000;
       acked_time_series.points.emplace_back(x, y);
 #if !(BWE_TEST_LOGGING_COMPILE_TIME_ENABLE)
@@ -1164,7 +1181,7 @@
     if (observer.GetAndResetBitrateUpdated() ||
         time_us - last_update_us >= 1e6) {
       uint32_t y = observer.last_bitrate_bps() / 1000;
-      float x = ToCallTime(clock.TimeInMicroseconds());
+      float x = ToCallTimeSec(clock.TimeInMicroseconds());
       time_series.points.emplace_back(x, y);
       last_update_us = time_us;
     }
@@ -1175,7 +1192,8 @@
   plot->AppendTimeSeries(std::move(acked_time_series));
   plot->AppendTimeSeriesIfNotEmpty(std::move(acked_estimate_time_series));
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   plot->SetTitle("Simulated send-side BWE behavior");
 }
@@ -1238,13 +1256,13 @@
     rtc::Optional<uint32_t> bitrate_bps = acked_bitrate.Rate(arrival_time_ms);
     if (bitrate_bps) {
       uint32_t y = *bitrate_bps / 1000;
-      float x = ToCallTime(clock.TimeInMicroseconds());
+      float x = ToCallTimeSec(clock.TimeInMicroseconds());
       acked_time_series.points.emplace_back(x, y);
     }
     if (packet_router.GetAndResetBitrateUpdated() ||
         clock.TimeInMicroseconds() - last_update_us >= 1e6) {
       uint32_t y = packet_router.last_bitrate_bps() / 1000;
-      float x = ToCallTime(clock.TimeInMicroseconds());
+      float x = ToCallTimeSec(clock.TimeInMicroseconds());
       time_series.points.emplace_back(x, y);
       last_update_us = clock.TimeInMicroseconds();
     }
@@ -1253,7 +1271,8 @@
   plot->AppendTimeSeries(std::move(time_series));
   plot->AppendTimeSeries(std::move(acked_time_series));
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   plot->SetTitle("Simulated receive-side BWE behavior");
 }
@@ -1308,7 +1327,7 @@
           feedback_adapter.GetTransportFeedbackVector();
       SortPacketFeedbackVector(&feedback);
       for (const PacketFeedback& packet : feedback) {
-        float x = ToCallTime(clock.TimeInMicroseconds());
+        float x = ToCallTimeSec(clock.TimeInMicroseconds());
         if (packet.send_time_ms == PacketFeedback::kNoSendTime) {
           late_feedback_series.points.emplace_back(x, prev_y);
           continue;
@@ -1346,7 +1365,8 @@
   plot->AppendTimeSeriesIfNotEmpty(std::move(time_series));
   plot->AppendTimeSeriesIfNotEmpty(std::move(late_feedback_series));
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Delay (ms)", kBottomMargin, kTopMargin);
   plot->SetTitle("Network Delay Change.");
 }
@@ -1393,14 +1413,15 @@
       double send_time_ms =
           static_cast<double>(packet.rtp.log_time_us() - first_send_timestamp) /
           1000;
-      float x = ToCallTime(packet.rtp.log_time_us());
+      float x = ToCallTimeSec(packet.rtp.log_time_us());
       float y = send_time_ms - capture_time_ms;
       pacer_delay_series.points.emplace_back(x, y);
     }
     plot->AppendTimeSeries(std::move(pacer_delay_series));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Pacer delay (ms)", kBottomMargin, kTopMargin);
   plot->SetTitle(
       "Delay from capture to send time. (First packet normalized to 0.)");
@@ -1413,7 +1434,7 @@
         GetStreamName(direction, stream.ssrc) + " capture-time",
         LineStyle::kLine, PointStyle::kHighlight);
     for (const auto& packet : stream.packet_view) {
-      float x = ToCallTime(packet.log_time_us());
+      float x = ToCallTimeSec(packet.log_time_us());
       float y = packet.header.timestamp;
       rtp_timestamps.points.emplace_back(x, y);
     }
@@ -1427,14 +1448,15 @@
     for (const auto& rtcp : sender_reports) {
       if (rtcp.sr.sender_ssrc() != stream.ssrc)
         continue;
-      float x = ToCallTime(rtcp.log_time_us());
+      float x = ToCallTimeSec(rtcp.log_time_us());
       float y = rtcp.sr.rtp_timestamp();
       rtcp_timestamps.points.emplace_back(x, y);
     }
     plot->AppendTimeSeriesIfNotEmpty(std::move(rtcp_timestamps));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "RTP timestamp", kBottomMargin, kTopMargin);
   plot->SetTitle(GetDirectionAsString(direction) + " timestamps");
 }
@@ -1449,11 +1471,15 @@
           static_cast<float>(*ana_event.config.bitrate_bps));
     return rtc::nullopt;
   };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaBitrateBps, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaBitrateBps,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Bitrate (bps)", kBottomMargin, kTopMargin);
   plot->SetTitle("Reported audio encoder target bitrate");
 }
@@ -1468,11 +1494,15 @@
               static_cast<float>(*ana_event.config.frame_length_ms));
         return rtc::Optional<float>();
       };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaFrameLengthMs, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaFrameLengthMs,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Frame length (ms)", kBottomMargin, kTopMargin);
   plot->SetTitle("Reported audio encoder frame length");
 }
@@ -1487,11 +1517,15 @@
               *ana_event.config.uplink_packet_loss_fraction));
         return rtc::Optional<float>();
       };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaPacketLoss, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaPacketLoss,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 10, "Percent lost packets", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("Reported audio encoder lost packets");
@@ -1507,11 +1541,15 @@
               static_cast<float>(*ana_event.config.enable_fec));
         return rtc::Optional<float>();
       };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaFecEnabled, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaFecEnabled,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "FEC (false/true)", kBottomMargin, kTopMargin);
   plot->SetTitle("Reported audio encoder FEC");
 }
@@ -1526,11 +1564,15 @@
               static_cast<float>(*ana_event.config.enable_dtx));
         return rtc::Optional<float>();
       };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaDtxEnabled, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaDtxEnabled,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "DTX (false/true)", kBottomMargin, kTopMargin);
   plot->SetTitle("Reported audio encoder DTX");
 }
@@ -1545,11 +1587,15 @@
               static_cast<float>(*ana_event.config.num_channels));
         return rtc::Optional<float>();
       };
+  auto ToCallTime = [this](const LoggedAudioNetworkAdaptationEvent& packet) {
+    return this->ToCallTimeSec(packet.log_time_us());
+  };
   ProcessPoints<LoggedAudioNetworkAdaptationEvent>(
-      GetAnaNumChannels, parsed_log_.audio_network_adaptation_events(),
-      begin_time_, &time_series);
+      ToCallTime, GetAnaNumChannels,
+      parsed_log_.audio_network_adaptation_events(), &time_series);
   plot->AppendTimeSeries(std::move(time_series));
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Number of channels (1 (mono)/2 (stereo))",
                           kBottomMargin, kTopMargin);
   plot->SetTitle("Reported audio encoder number of channels");
@@ -1802,7 +1848,8 @@
     plot->AppendTimeSeries(std::move(series.second));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetYAxis(min_y_axis, max_y_axis, "Relative delay (ms)", kBottomMargin,
                  kTopMargin);
   plot->SetTitle("NetEq timing for " + GetStreamName(kIncomingPacket, ssrc));
@@ -1825,7 +1872,7 @@
     const auto& stats = st.second->stats();
 
     for (size_t i = 0; i < stats.size(); ++i) {
-      const float time = ToCallTime(stats[i].first * 1000);  // ms to us.
+      const float time = ToCallTimeSec(stats[i].first * 1000);  // ms to us.
       const float value = stats_extractor(stats[i].second);
       time_series[ssrc].points.emplace_back(TimeSeriesPoint(time, value));
       min_y_axis = std::min(min_y_axis, value);
@@ -1839,7 +1886,8 @@
     plot->AppendTimeSeries(std::move(series.second));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetYAxis(min_y_axis, max_y_axis, plot_name, kBottomMargin, kTopMargin);
   plot->SetTitle(plot_name);
 }
@@ -1858,7 +1906,7 @@
       candidate_pair_desc_by_id_[config.candidate_pair_id] =
           candidate_pair_desc;
     }
-    float x = ToCallTime(config.log_time_us());
+    float x = ToCallTimeSec(config.log_time_us());
     float y = static_cast<float>(config.type);
     configs_by_cp_id[config.candidate_pair_id].points.emplace_back(x, y);
   }
@@ -1870,7 +1918,8 @@
     plot->AppendTimeSeries(std::move(kv.second));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 3, "Numeric Config Type", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("[IceEventLog] ICE candidate pair configs");
@@ -1906,7 +1955,7 @@
               GetCandidatePairLogDescriptionFromId(event.candidate_pair_id),
           LineStyle::kNone, PointStyle::kHighlight);
     }
-    float x = ToCallTime(event.log_time_us());
+    float x = ToCallTimeSec(event.log_time_us());
     float y = static_cast<float>(event.type);
     checks_by_cp_id[event.candidate_pair_id].points.emplace_back(x, y);
   }
@@ -1916,7 +1965,8 @@
     plot->AppendTimeSeries(std::move(kv.second));
   }
 
-  plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
+  plot->SetXAxis(ToCallTimeSec(begin_time_), call_duration_s_, "Time (s)",
+                 kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 4, "Numeric Connectivity State", kBottomMargin,
                           kTopMargin);
   plot->SetTitle("[IceEventLog] ICE connectivity checks");
@@ -1980,7 +2030,7 @@
       int64_t seq_num = seq_num_unwrapper.Unwrap(packet.header.sequenceNumber);
       if (last_seq_num.has_value() &&
           std::abs(seq_num - last_seq_num.value()) > kMaxSeqNumJump) {
-        Alert_SeqNumJump(direction, ToCallTime(packet.log_time_us()),
+        Alert_SeqNumJump(direction, ToCallTimeSec(packet.log_time_us()),
                          packet.header.ssrc);
       }
       last_seq_num.emplace(seq_num);
@@ -1990,7 +2040,7 @@
       if (last_capture_time.has_value() &&
           std::abs(capture_time - last_capture_time.value()) >
               kMaxCaptureTimeJump) {
-        Alert_CaptureTimeJump(direction, ToCallTime(packet.log_time_us()),
+        Alert_CaptureTimeJump(direction, ToCallTimeSec(packet.log_time_us()),
                               packet.header.ssrc);
       }
       last_capture_time.emplace(capture_time);
@@ -2022,7 +2072,7 @@
     int64_t duration = timestamp - last_rtp_time.value_or(0);
     if (last_rtp_time.has_value() && duration > kMaxRtpTransmissionGap) {
       // No packet sent/received for more than 500 ms.
-      Alert_RtpLogTimeGap(direction, ToCallTime(timestamp), duration / 1000);
+      Alert_RtpLogTimeGap(direction, ToCallTimeSec(timestamp), duration / 1000);
     }
     last_rtp_time.emplace(timestamp);
   }
@@ -2037,7 +2087,7 @@
       int64_t duration = rtcp.log_time_us() - last_rtcp_time.value_or(0);
       if (last_rtcp_time.has_value() && duration > kMaxRtcpTransmissionGap) {
         // No feedback sent/received for more than 2000 ms.
-        Alert_RtcpLogTimeGap(direction, ToCallTime(rtcp.log_time_us()),
+        Alert_RtcpLogTimeGap(direction, ToCallTimeSec(rtcp.log_time_us()),
                              duration / 1000);
       }
       last_rtcp_time.emplace(rtcp.log_time_us());
@@ -2051,7 +2101,7 @@
       int64_t duration = rtcp.log_time_us() - last_rtcp_time.value_or(0);
       if (last_rtcp_time.has_value() && duration > kMaxRtcpTransmissionGap) {
         // No feedback sent/received for more than 2000 ms.
-        Alert_RtcpLogTimeGap(direction, ToCallTime(rtcp.log_time_us()),
+        Alert_RtcpLogTimeGap(direction, ToCallTimeSec(rtcp.log_time_us()),
                              duration / 1000);
       }
       last_rtcp_time.emplace(rtcp.log_time_us());
diff --git a/rtc_tools/event_log_visualizer/analyzer.h b/rtc_tools/event_log_visualizer/analyzer.h
index 51ae015..d4a7fc3 100644
--- a/rtc_tools/event_log_visualizer/analyzer.h
+++ b/rtc_tools/event_log_visualizer/analyzer.h
@@ -31,7 +31,7 @@
   // The EventLogAnalyzer keeps a reference to the ParsedRtcEventLogNew for the
   // duration of its lifetime. The ParsedRtcEventLogNew must not be destroyed or
   // modified while the EventLogAnalyzer is being used.
-  explicit EventLogAnalyzer(const ParsedRtcEventLogNew& log);
+  EventLogAnalyzer(const ParsedRtcEventLogNew& log, bool normalize_time);
 
   void CreatePacketGraph(PacketDirection direction, Plot* plot);
 
@@ -151,7 +151,8 @@
     return name.str();
   }
 
-  float ToCallTime(int64_t timestamp) const;
+  int64_t ToCallTimeUs(int64_t timestamp) const;
+  float ToCallTimeSec(int64_t timestamp) const;
 
   void Alert_RtpLogTimeGap(PacketDirection direction,
                            float time_seconds,
@@ -231,6 +232,7 @@
   // First and last events of the log.
   int64_t begin_time_;
   int64_t end_time_;
+  const bool normalize_time_;
 
   // Duration (in seconds) of log file.
   float call_duration_s_;
diff --git a/rtc_tools/event_log_visualizer/main.cc b/rtc_tools/event_log_visualizer/main.cc
index 221b040..802633c 100644
--- a/rtc_tools/event_log_visualizer/main.cc
+++ b/rtc_tools/event_log_visualizer/main.cc
@@ -151,6 +151,10 @@
             false,
             "Print triage alerts, i.e. a list of potential problems.");
 
+DEFINE_bool(normalize_time,
+            true,
+            "Normalize the log timestamps so that the call starts at time 0.");
+
 void SetAllPlotFlags(bool setting);
 
 
@@ -227,7 +231,7 @@
               << std::endl;
   }
 
-  webrtc::EventLogAnalyzer analyzer(parsed_log);
+  webrtc::EventLogAnalyzer analyzer(parsed_log, FLAG_normalize_time);
   std::unique_ptr<webrtc::PlotCollection> collection(
       new webrtc::PythonPlotCollection());
 
diff --git a/rtc_tools/event_log_visualizer/plot_base.cc b/rtc_tools/event_log_visualizer/plot_base.cc
index 9a21393..0847cfe 100644
--- a/rtc_tools/event_log_visualizer/plot_base.cc
+++ b/rtc_tools/event_log_visualizer/plot_base.cc
@@ -11,6 +11,7 @@
 #include "rtc_tools/event_log_visualizer/plot_base.h"
 
 #include <algorithm>
+#include <limits>
 
 #include "rtc_base/checks.h"
 
diff --git a/rtc_tools/event_log_visualizer/plot_python.cc b/rtc_tools/event_log_visualizer/plot_python.cc
index 37c4d84..3808e87 100644
--- a/rtc_tools/event_log_visualizer/plot_python.cc
+++ b/rtc_tools/event_log_visualizer/plot_python.cc
@@ -38,9 +38,9 @@
       // List x coordinates
       printf("x%zu = [", i);
       if (series_list_[i].points.size() > 0)
-        printf("%G", series_list_[i].points[0].x);
+        printf("%.3f", series_list_[i].points[0].x);
       for (size_t j = 1; j < series_list_[i].points.size(); j++)
-        printf(", %G", series_list_[i].points[j].x);
+        printf(", %.3f", series_list_[i].points[j].x);
       printf("]\n");
 
       // List y coordinates