Fork a few VideoReceiveStream related classes.

We'll need to deprecate the previous classes due to being used externally
as an API.

Bug: webrtc:11489
Change-Id: I64de29c8adae304d0b7628e24dd0abc5be6387ba
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/173960
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31136}
diff --git a/video/receive_statistics_proxy2.cc b/video/receive_statistics_proxy2.cc
new file mode 100644
index 0000000..50b1ea0
--- /dev/null
+++ b/video/receive_statistics_proxy2.cc
@@ -0,0 +1,943 @@
+/*
+ *  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.
+ */
+
+#include "video/receive_statistics_proxy2.h"
+
+#include <algorithm>
+#include <cmath>
+#include <utility>
+
+#include "modules/video_coding/include/video_codec_interface.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+#include "rtc_base/time_utils.h"
+#include "system_wrappers/include/clock.h"
+#include "system_wrappers/include/field_trial.h"
+#include "system_wrappers/include/metrics.h"
+
+namespace webrtc {
+namespace internal {
+namespace {
+// Periodic time interval for processing samples for |freq_offset_counter_|.
+const int64_t kFreqOffsetProcessIntervalMs = 40000;
+
+// Configuration for bad call detection.
+const int kBadCallMinRequiredSamples = 10;
+const int kMinSampleLengthMs = 990;
+const int kNumMeasurements = 10;
+const int kNumMeasurementsVariance = kNumMeasurements * 1.5;
+const float kBadFraction = 0.8f;
+// For fps:
+// Low means low enough to be bad, high means high enough to be good
+const int kLowFpsThreshold = 12;
+const int kHighFpsThreshold = 14;
+// For qp and fps variance:
+// Low means low enough to be good, high means high enough to be bad
+const int kLowQpThresholdVp8 = 60;
+const int kHighQpThresholdVp8 = 70;
+const int kLowVarianceThreshold = 1;
+const int kHighVarianceThreshold = 2;
+
+// Some metrics are reported as a maximum over this period.
+// This should be synchronized with a typical getStats polling interval in
+// the clients.
+const int kMovingMaxWindowMs = 1000;
+
+// How large window we use to calculate the framerate/bitrate.
+const int kRateStatisticsWindowSizeMs = 1000;
+
+// Some sane ballpark estimate for maximum common value of inter-frame delay.
+// Values below that will be stored explicitly in the array,
+// values above - in the map.
+const int kMaxCommonInterframeDelayMs = 500;
+
+const char* UmaPrefixForContentType(VideoContentType content_type) {
+  if (videocontenttypehelpers::IsScreenshare(content_type))
+    return "WebRTC.Video.Screenshare";
+  return "WebRTC.Video";
+}
+
+std::string UmaSuffixForContentType(VideoContentType content_type) {
+  char ss_buf[1024];
+  rtc::SimpleStringBuilder ss(ss_buf);
+  int simulcast_id = videocontenttypehelpers::GetSimulcastId(content_type);
+  if (simulcast_id > 0) {
+    ss << ".S" << simulcast_id - 1;
+  }
+  int experiment_id = videocontenttypehelpers::GetExperimentId(content_type);
+  if (experiment_id > 0) {
+    ss << ".ExperimentGroup" << experiment_id - 1;
+  }
+  return ss.str();
+}
+
+}  // namespace
+
+ReceiveStatisticsProxy::ReceiveStatisticsProxy(
+    const VideoReceiveStream::Config* config,
+    Clock* clock)
+    : clock_(clock),
+      config_(*config),
+      start_ms_(clock->TimeInMilliseconds()),
+      enable_decode_time_histograms_(
+          !field_trial::IsEnabled("WebRTC-DecodeTimeHistogramsKillSwitch")),
+      last_sample_time_(clock->TimeInMilliseconds()),
+      fps_threshold_(kLowFpsThreshold,
+                     kHighFpsThreshold,
+                     kBadFraction,
+                     kNumMeasurements),
+      qp_threshold_(kLowQpThresholdVp8,
+                    kHighQpThresholdVp8,
+                    kBadFraction,
+                    kNumMeasurements),
+      variance_threshold_(kLowVarianceThreshold,
+                          kHighVarianceThreshold,
+                          kBadFraction,
+                          kNumMeasurementsVariance),
+      num_bad_states_(0),
+      num_certain_states_(0),
+      // 1000ms window, scale 1000 for ms to s.
+      decode_fps_estimator_(1000, 1000),
+      renders_fps_estimator_(1000, 1000),
+      render_fps_tracker_(100, 10u),
+      render_pixel_tracker_(100, 10u),
+      video_quality_observer_(
+          new VideoQualityObserver(VideoContentType::UNSPECIFIED)),
+      interframe_delay_max_moving_(kMovingMaxWindowMs),
+      freq_offset_counter_(clock, nullptr, kFreqOffsetProcessIntervalMs),
+      avg_rtt_ms_(0),
+      last_content_type_(VideoContentType::UNSPECIFIED),
+      last_codec_type_(kVideoCodecVP8),
+      num_delayed_frames_rendered_(0),
+      sum_missed_render_deadline_ms_(0),
+      timing_frame_info_counter_(kMovingMaxWindowMs) {
+  decode_thread_.Detach();
+  network_thread_.Detach();
+  stats_.ssrc = config_.rtp.remote_ssrc;
+}
+
+void ReceiveStatisticsProxy::UpdateHistograms(
+    absl::optional<int> fraction_lost,
+    const StreamDataCounters& rtp_stats,
+    const StreamDataCounters* rtx_stats) {
+  // Not actually running on the decoder thread, but must be called after
+  // DecoderThreadStopped, which detaches the thread checker. It is therefore
+  // safe to access |qp_counters_|, which were updated on the decode thread
+  // earlier.
+  RTC_DCHECK_RUN_ON(&decode_thread_);
+
+  rtc::CritScope lock(&crit_);
+
+  char log_stream_buf[8 * 1024];
+  rtc::SimpleStringBuilder log_stream(log_stream_buf);
+  int stream_duration_sec = (clock_->TimeInMilliseconds() - start_ms_) / 1000;
+  if (stats_.frame_counts.key_frames > 0 ||
+      stats_.frame_counts.delta_frames > 0) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Video.ReceiveStreamLifetimeInSeconds",
+                                stream_duration_sec);
+    log_stream << "WebRTC.Video.ReceiveStreamLifetimeInSeconds "
+               << stream_duration_sec << '\n';
+  }
+
+  log_stream << "Frames decoded " << stats_.frames_decoded << '\n';
+
+  if (num_unique_frames_) {
+    int num_dropped_frames = *num_unique_frames_ - stats_.frames_decoded;
+    RTC_HISTOGRAM_COUNTS_1000("WebRTC.Video.DroppedFrames.Receiver",
+                              num_dropped_frames);
+    log_stream << "WebRTC.Video.DroppedFrames.Receiver " << num_dropped_frames
+               << '\n';
+  }
+
+  if (fraction_lost && stream_duration_sec >= metrics::kMinRunTimeInSeconds) {
+    RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.ReceivedPacketsLostInPercent",
+                             *fraction_lost);
+    log_stream << "WebRTC.Video.ReceivedPacketsLostInPercent " << *fraction_lost
+               << '\n';
+  }
+
+  if (first_decoded_frame_time_ms_) {
+    const int64_t elapsed_ms =
+        (clock_->TimeInMilliseconds() - *first_decoded_frame_time_ms_);
+    if (elapsed_ms >=
+        metrics::kMinRunTimeInSeconds * rtc::kNumMillisecsPerSec) {
+      int decoded_fps = static_cast<int>(
+          (stats_.frames_decoded * 1000.0f / elapsed_ms) + 0.5f);
+      RTC_HISTOGRAM_COUNTS_100("WebRTC.Video.DecodedFramesPerSecond",
+                               decoded_fps);
+      log_stream << "WebRTC.Video.DecodedFramesPerSecond " << decoded_fps
+                 << '\n';
+
+      const uint32_t frames_rendered = stats_.frames_rendered;
+      if (frames_rendered > 0) {
+        RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.DelayedFramesToRenderer",
+                                 static_cast<int>(num_delayed_frames_rendered_ *
+                                                  100 / frames_rendered));
+        if (num_delayed_frames_rendered_ > 0) {
+          RTC_HISTOGRAM_COUNTS_1000(
+              "WebRTC.Video.DelayedFramesToRenderer_AvgDelayInMs",
+              static_cast<int>(sum_missed_render_deadline_ms_ /
+                               num_delayed_frames_rendered_));
+        }
+      }
+    }
+  }
+
+  const int kMinRequiredSamples = 200;
+  int samples = static_cast<int>(render_fps_tracker_.TotalSampleCount());
+  if (samples >= kMinRequiredSamples) {
+    int rendered_fps = round(render_fps_tracker_.ComputeTotalRate());
+    RTC_HISTOGRAM_COUNTS_100("WebRTC.Video.RenderFramesPerSecond",
+                             rendered_fps);
+    log_stream << "WebRTC.Video.RenderFramesPerSecond " << rendered_fps << '\n';
+    RTC_HISTOGRAM_COUNTS_100000(
+        "WebRTC.Video.RenderSqrtPixelsPerSecond",
+        round(render_pixel_tracker_.ComputeTotalRate()));
+  }
+
+  absl::optional<int> sync_offset_ms =
+      sync_offset_counter_.Avg(kMinRequiredSamples);
+  if (sync_offset_ms) {
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.AVSyncOffsetInMs",
+                               *sync_offset_ms);
+    log_stream << "WebRTC.Video.AVSyncOffsetInMs " << *sync_offset_ms << '\n';
+  }
+  AggregatedStats freq_offset_stats = freq_offset_counter_.GetStats();
+  if (freq_offset_stats.num_samples > 0) {
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.RtpToNtpFreqOffsetInKhz",
+                               freq_offset_stats.average);
+    log_stream << "WebRTC.Video.RtpToNtpFreqOffsetInKhz "
+               << freq_offset_stats.ToString() << '\n';
+  }
+
+  int num_total_frames =
+      stats_.frame_counts.key_frames + stats_.frame_counts.delta_frames;
+  if (num_total_frames >= kMinRequiredSamples) {
+    int num_key_frames = stats_.frame_counts.key_frames;
+    int key_frames_permille =
+        (num_key_frames * 1000 + num_total_frames / 2) / num_total_frames;
+    RTC_HISTOGRAM_COUNTS_1000("WebRTC.Video.KeyFramesReceivedInPermille",
+                              key_frames_permille);
+    log_stream << "WebRTC.Video.KeyFramesReceivedInPermille "
+               << key_frames_permille << '\n';
+  }
+
+  absl::optional<int> qp = qp_counters_.vp8.Avg(kMinRequiredSamples);
+  if (qp) {
+    RTC_HISTOGRAM_COUNTS_200("WebRTC.Video.Decoded.Vp8.Qp", *qp);
+    log_stream << "WebRTC.Video.Decoded.Vp8.Qp " << *qp << '\n';
+  }
+  absl::optional<int> decode_ms = decode_time_counter_.Avg(kMinRequiredSamples);
+  if (decode_ms) {
+    RTC_HISTOGRAM_COUNTS_1000("WebRTC.Video.DecodeTimeInMs", *decode_ms);
+    log_stream << "WebRTC.Video.DecodeTimeInMs " << *decode_ms << '\n';
+  }
+  absl::optional<int> jb_delay_ms =
+      jitter_buffer_delay_counter_.Avg(kMinRequiredSamples);
+  if (jb_delay_ms) {
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.JitterBufferDelayInMs",
+                               *jb_delay_ms);
+    log_stream << "WebRTC.Video.JitterBufferDelayInMs " << *jb_delay_ms << '\n';
+  }
+
+  absl::optional<int> target_delay_ms =
+      target_delay_counter_.Avg(kMinRequiredSamples);
+  if (target_delay_ms) {
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.TargetDelayInMs",
+                               *target_delay_ms);
+    log_stream << "WebRTC.Video.TargetDelayInMs " << *target_delay_ms << '\n';
+  }
+  absl::optional<int> current_delay_ms =
+      current_delay_counter_.Avg(kMinRequiredSamples);
+  if (current_delay_ms) {
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.CurrentDelayInMs",
+                               *current_delay_ms);
+    log_stream << "WebRTC.Video.CurrentDelayInMs " << *current_delay_ms << '\n';
+  }
+  absl::optional<int> delay_ms = delay_counter_.Avg(kMinRequiredSamples);
+  if (delay_ms)
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.OnewayDelayInMs", *delay_ms);
+
+  // Aggregate content_specific_stats_ by removing experiment or simulcast
+  // information;
+  std::map<VideoContentType, ContentSpecificStats> aggregated_stats;
+  for (const auto& it : content_specific_stats_) {
+    // Calculate simulcast specific metrics (".S0" ... ".S2" suffixes).
+    VideoContentType content_type = it.first;
+    if (videocontenttypehelpers::GetSimulcastId(content_type) > 0) {
+      // Aggregate on experiment id.
+      videocontenttypehelpers::SetExperimentId(&content_type, 0);
+      aggregated_stats[content_type].Add(it.second);
+    }
+    // Calculate experiment specific metrics (".ExperimentGroup[0-7]" suffixes).
+    content_type = it.first;
+    if (videocontenttypehelpers::GetExperimentId(content_type) > 0) {
+      // Aggregate on simulcast id.
+      videocontenttypehelpers::SetSimulcastId(&content_type, 0);
+      aggregated_stats[content_type].Add(it.second);
+    }
+    // Calculate aggregated metrics (no suffixes. Aggregated on everything).
+    content_type = it.first;
+    videocontenttypehelpers::SetSimulcastId(&content_type, 0);
+    videocontenttypehelpers::SetExperimentId(&content_type, 0);
+    aggregated_stats[content_type].Add(it.second);
+  }
+
+  for (const auto& it : aggregated_stats) {
+    // For the metric Foo we report the following slices:
+    // WebRTC.Video.Foo,
+    // WebRTC.Video.Screenshare.Foo,
+    // WebRTC.Video.Foo.S[0-3],
+    // WebRTC.Video.Foo.ExperimentGroup[0-7],
+    // WebRTC.Video.Screenshare.Foo.S[0-3],
+    // WebRTC.Video.Screenshare.Foo.ExperimentGroup[0-7].
+    auto content_type = it.first;
+    auto stats = it.second;
+    std::string uma_prefix = UmaPrefixForContentType(content_type);
+    std::string uma_suffix = UmaSuffixForContentType(content_type);
+    // Metrics can be sliced on either simulcast id or experiment id but not
+    // both.
+    RTC_DCHECK(videocontenttypehelpers::GetExperimentId(content_type) == 0 ||
+               videocontenttypehelpers::GetSimulcastId(content_type) == 0);
+
+    absl::optional<int> e2e_delay_ms =
+        stats.e2e_delay_counter.Avg(kMinRequiredSamples);
+    if (e2e_delay_ms) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".EndToEndDelayInMs" + uma_suffix, *e2e_delay_ms);
+      log_stream << uma_prefix << ".EndToEndDelayInMs" << uma_suffix << " "
+                 << *e2e_delay_ms << '\n';
+    }
+    absl::optional<int> e2e_delay_max_ms = stats.e2e_delay_counter.Max();
+    if (e2e_delay_max_ms && e2e_delay_ms) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_100000(
+          uma_prefix + ".EndToEndDelayMaxInMs" + uma_suffix, *e2e_delay_max_ms);
+      log_stream << uma_prefix << ".EndToEndDelayMaxInMs" << uma_suffix << " "
+                 << *e2e_delay_max_ms << '\n';
+    }
+    absl::optional<int> interframe_delay_ms =
+        stats.interframe_delay_counter.Avg(kMinRequiredSamples);
+    if (interframe_delay_ms) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".InterframeDelayInMs" + uma_suffix,
+          *interframe_delay_ms);
+      log_stream << uma_prefix << ".InterframeDelayInMs" << uma_suffix << " "
+                 << *interframe_delay_ms << '\n';
+    }
+    absl::optional<int> interframe_delay_max_ms =
+        stats.interframe_delay_counter.Max();
+    if (interframe_delay_max_ms && interframe_delay_ms) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".InterframeDelayMaxInMs" + uma_suffix,
+          *interframe_delay_max_ms);
+      log_stream << uma_prefix << ".InterframeDelayMaxInMs" << uma_suffix << " "
+                 << *interframe_delay_max_ms << '\n';
+    }
+
+    absl::optional<uint32_t> interframe_delay_95p_ms =
+        stats.interframe_delay_percentiles.GetPercentile(0.95f);
+    if (interframe_delay_95p_ms && interframe_delay_ms != -1) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".InterframeDelay95PercentileInMs" + uma_suffix,
+          *interframe_delay_95p_ms);
+      log_stream << uma_prefix << ".InterframeDelay95PercentileInMs"
+                 << uma_suffix << " " << *interframe_delay_95p_ms << '\n';
+    }
+
+    absl::optional<int> width = stats.received_width.Avg(kMinRequiredSamples);
+    if (width) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".ReceivedWidthInPixels" + uma_suffix, *width);
+      log_stream << uma_prefix << ".ReceivedWidthInPixels" << uma_suffix << " "
+                 << *width << '\n';
+    }
+
+    absl::optional<int> height = stats.received_height.Avg(kMinRequiredSamples);
+    if (height) {
+      RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+          uma_prefix + ".ReceivedHeightInPixels" + uma_suffix, *height);
+      log_stream << uma_prefix << ".ReceivedHeightInPixels" << uma_suffix << " "
+                 << *height << '\n';
+    }
+
+    if (content_type != VideoContentType::UNSPECIFIED) {
+      // Don't report these 3 metrics unsliced, as more precise variants
+      // are reported separately in this method.
+      float flow_duration_sec = stats.flow_duration_ms / 1000.0;
+      if (flow_duration_sec >= metrics::kMinRunTimeInSeconds) {
+        int media_bitrate_kbps = static_cast<int>(stats.total_media_bytes * 8 /
+                                                  flow_duration_sec / 1000);
+        RTC_HISTOGRAM_COUNTS_SPARSE_10000(
+            uma_prefix + ".MediaBitrateReceivedInKbps" + uma_suffix,
+            media_bitrate_kbps);
+        log_stream << uma_prefix << ".MediaBitrateReceivedInKbps" << uma_suffix
+                   << " " << media_bitrate_kbps << '\n';
+      }
+
+      int num_total_frames =
+          stats.frame_counts.key_frames + stats.frame_counts.delta_frames;
+      if (num_total_frames >= kMinRequiredSamples) {
+        int num_key_frames = stats.frame_counts.key_frames;
+        int key_frames_permille =
+            (num_key_frames * 1000 + num_total_frames / 2) / num_total_frames;
+        RTC_HISTOGRAM_COUNTS_SPARSE_1000(
+            uma_prefix + ".KeyFramesReceivedInPermille" + uma_suffix,
+            key_frames_permille);
+        log_stream << uma_prefix << ".KeyFramesReceivedInPermille" << uma_suffix
+                   << " " << key_frames_permille << '\n';
+      }
+
+      absl::optional<int> qp = stats.qp_counter.Avg(kMinRequiredSamples);
+      if (qp) {
+        RTC_HISTOGRAM_COUNTS_SPARSE_200(
+            uma_prefix + ".Decoded.Vp8.Qp" + uma_suffix, *qp);
+        log_stream << uma_prefix << ".Decoded.Vp8.Qp" << uma_suffix << " "
+                   << *qp << '\n';
+      }
+    }
+  }
+
+  StreamDataCounters rtp_rtx_stats = rtp_stats;
+  if (rtx_stats)
+    rtp_rtx_stats.Add(*rtx_stats);
+  int64_t elapsed_sec =
+      rtp_rtx_stats.TimeSinceFirstPacketInMs(clock_->TimeInMilliseconds()) /
+      1000;
+  if (elapsed_sec >= metrics::kMinRunTimeInSeconds) {
+    RTC_HISTOGRAM_COUNTS_10000(
+        "WebRTC.Video.BitrateReceivedInKbps",
+        static_cast<int>(rtp_rtx_stats.transmitted.TotalBytes() * 8 /
+                         elapsed_sec / 1000));
+    int media_bitrate_kbs = static_cast<int>(rtp_stats.MediaPayloadBytes() * 8 /
+                                             elapsed_sec / 1000);
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.MediaBitrateReceivedInKbps",
+                               media_bitrate_kbs);
+    log_stream << "WebRTC.Video.MediaBitrateReceivedInKbps "
+               << media_bitrate_kbs << '\n';
+    RTC_HISTOGRAM_COUNTS_10000(
+        "WebRTC.Video.PaddingBitrateReceivedInKbps",
+        static_cast<int>(rtp_rtx_stats.transmitted.padding_bytes * 8 /
+                         elapsed_sec / 1000));
+    RTC_HISTOGRAM_COUNTS_10000(
+        "WebRTC.Video.RetransmittedBitrateReceivedInKbps",
+        static_cast<int>(rtp_rtx_stats.retransmitted.TotalBytes() * 8 /
+                         elapsed_sec / 1000));
+    if (rtx_stats) {
+      RTC_HISTOGRAM_COUNTS_10000(
+          "WebRTC.Video.RtxBitrateReceivedInKbps",
+          static_cast<int>(rtx_stats->transmitted.TotalBytes() * 8 /
+                           elapsed_sec / 1000));
+    }
+    const RtcpPacketTypeCounter& counters = stats_.rtcp_packet_type_counts;
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.NackPacketsSentPerMinute",
+                               counters.nack_packets * 60 / elapsed_sec);
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.FirPacketsSentPerMinute",
+                               counters.fir_packets * 60 / elapsed_sec);
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.PliPacketsSentPerMinute",
+                               counters.pli_packets * 60 / elapsed_sec);
+    if (counters.nack_requests > 0) {
+      RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.UniqueNackRequestsSentInPercent",
+                               counters.UniqueNackRequestsInPercent());
+    }
+  }
+
+  if (num_certain_states_ >= kBadCallMinRequiredSamples) {
+    RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.BadCall.Any",
+                             100 * num_bad_states_ / num_certain_states_);
+  }
+  absl::optional<double> fps_fraction =
+      fps_threshold_.FractionHigh(kBadCallMinRequiredSamples);
+  if (fps_fraction) {
+    RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.BadCall.FrameRate",
+                             static_cast<int>(100 * (1 - *fps_fraction)));
+  }
+  absl::optional<double> variance_fraction =
+      variance_threshold_.FractionHigh(kBadCallMinRequiredSamples);
+  if (variance_fraction) {
+    RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.BadCall.FrameRateVariance",
+                             static_cast<int>(100 * *variance_fraction));
+  }
+  absl::optional<double> qp_fraction =
+      qp_threshold_.FractionHigh(kBadCallMinRequiredSamples);
+  if (qp_fraction) {
+    RTC_HISTOGRAM_PERCENTAGE("WebRTC.Video.BadCall.Qp",
+                             static_cast<int>(100 * *qp_fraction));
+  }
+
+  RTC_LOG(LS_INFO) << log_stream.str();
+  video_quality_observer_->UpdateHistograms();
+}
+
+void ReceiveStatisticsProxy::QualitySample() {
+  int64_t now = clock_->TimeInMilliseconds();
+  if (last_sample_time_ + kMinSampleLengthMs > now)
+    return;
+
+  double fps =
+      render_fps_tracker_.ComputeRateForInterval(now - last_sample_time_);
+  absl::optional<int> qp = qp_sample_.Avg(1);
+
+  bool prev_fps_bad = !fps_threshold_.IsHigh().value_or(true);
+  bool prev_qp_bad = qp_threshold_.IsHigh().value_or(false);
+  bool prev_variance_bad = variance_threshold_.IsHigh().value_or(false);
+  bool prev_any_bad = prev_fps_bad || prev_qp_bad || prev_variance_bad;
+
+  fps_threshold_.AddMeasurement(static_cast<int>(fps));
+  if (qp)
+    qp_threshold_.AddMeasurement(*qp);
+  absl::optional<double> fps_variance_opt = fps_threshold_.CalculateVariance();
+  double fps_variance = fps_variance_opt.value_or(0);
+  if (fps_variance_opt) {
+    variance_threshold_.AddMeasurement(static_cast<int>(fps_variance));
+  }
+
+  bool fps_bad = !fps_threshold_.IsHigh().value_or(true);
+  bool qp_bad = qp_threshold_.IsHigh().value_or(false);
+  bool variance_bad = variance_threshold_.IsHigh().value_or(false);
+  bool any_bad = fps_bad || qp_bad || variance_bad;
+
+  if (!prev_any_bad && any_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (any) start: " << now;
+  } else if (prev_any_bad && !any_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (any) end: " << now;
+  }
+
+  if (!prev_fps_bad && fps_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (fps) start: " << now;
+  } else if (prev_fps_bad && !fps_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (fps) end: " << now;
+  }
+
+  if (!prev_qp_bad && qp_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (qp) start: " << now;
+  } else if (prev_qp_bad && !qp_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (qp) end: " << now;
+  }
+
+  if (!prev_variance_bad && variance_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (variance) start: " << now;
+  } else if (prev_variance_bad && !variance_bad) {
+    RTC_LOG(LS_INFO) << "Bad call (variance) end: " << now;
+  }
+
+  RTC_LOG(LS_VERBOSE) << "SAMPLE: sample_length: " << (now - last_sample_time_)
+                      << " fps: " << fps << " fps_bad: " << fps_bad
+                      << " qp: " << qp.value_or(-1) << " qp_bad: " << qp_bad
+                      << " variance_bad: " << variance_bad
+                      << " fps_variance: " << fps_variance;
+
+  last_sample_time_ = now;
+  qp_sample_.Reset();
+
+  if (fps_threshold_.IsHigh() || variance_threshold_.IsHigh() ||
+      qp_threshold_.IsHigh()) {
+    if (any_bad)
+      ++num_bad_states_;
+    ++num_certain_states_;
+  }
+}
+
+void ReceiveStatisticsProxy::UpdateFramerate(int64_t now_ms) const {
+  int64_t old_frames_ms = now_ms - kRateStatisticsWindowSizeMs;
+  while (!frame_window_.empty() &&
+         frame_window_.begin()->first < old_frames_ms) {
+    frame_window_.erase(frame_window_.begin());
+  }
+
+  size_t framerate =
+      (frame_window_.size() * 1000 + 500) / kRateStatisticsWindowSizeMs;
+  stats_.network_frame_rate = static_cast<int>(framerate);
+}
+
+void ReceiveStatisticsProxy::UpdateDecodeTimeHistograms(
+    int width,
+    int height,
+    int decode_time_ms) const {
+  bool is_4k = (width == 3840 || width == 4096) && height == 2160;
+  bool is_hd = width == 1920 && height == 1080;
+  // Only update histograms for 4k/HD and VP9/H264.
+  if ((is_4k || is_hd) && (last_codec_type_ == kVideoCodecVP9 ||
+                           last_codec_type_ == kVideoCodecH264)) {
+    const std::string kDecodeTimeUmaPrefix =
+        "WebRTC.Video.DecodeTimePerFrameInMs.";
+
+    // Each histogram needs its own line for it to not be reused in the wrong
+    // way when the format changes.
+    if (last_codec_type_ == kVideoCodecVP9) {
+      bool is_sw_decoder =
+          stats_.decoder_implementation_name.compare(0, 6, "libvpx") == 0;
+      if (is_4k) {
+        if (is_sw_decoder)
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "Vp9.4k.Sw",
+                                    decode_time_ms);
+        else
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "Vp9.4k.Hw",
+                                    decode_time_ms);
+      } else {
+        if (is_sw_decoder)
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "Vp9.Hd.Sw",
+                                    decode_time_ms);
+        else
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "Vp9.Hd.Hw",
+                                    decode_time_ms);
+      }
+    } else {
+      bool is_sw_decoder =
+          stats_.decoder_implementation_name.compare(0, 6, "FFmpeg") == 0;
+      if (is_4k) {
+        if (is_sw_decoder)
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "H264.4k.Sw",
+                                    decode_time_ms);
+        else
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "H264.4k.Hw",
+                                    decode_time_ms);
+
+      } else {
+        if (is_sw_decoder)
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "H264.Hd.Sw",
+                                    decode_time_ms);
+        else
+          RTC_HISTOGRAM_COUNTS_1000(kDecodeTimeUmaPrefix + "H264.Hd.Hw",
+                                    decode_time_ms);
+      }
+    }
+  }
+}
+
+absl::optional<int64_t>
+ReceiveStatisticsProxy::GetCurrentEstimatedPlayoutNtpTimestampMs(
+    int64_t now_ms) const {
+  if (!last_estimated_playout_ntp_timestamp_ms_ ||
+      !last_estimated_playout_time_ms_) {
+    return absl::nullopt;
+  }
+  int64_t elapsed_ms = now_ms - *last_estimated_playout_time_ms_;
+  return *last_estimated_playout_ntp_timestamp_ms_ + elapsed_ms;
+}
+
+VideoReceiveStream::Stats ReceiveStatisticsProxy::GetStats() const {
+  rtc::CritScope lock(&crit_);
+  // Get current frame rates here, as only updating them on new frames prevents
+  // us from ever correctly displaying frame rate of 0.
+  int64_t now_ms = clock_->TimeInMilliseconds();
+  UpdateFramerate(now_ms);
+  stats_.render_frame_rate = renders_fps_estimator_.Rate(now_ms).value_or(0);
+  stats_.decode_frame_rate = decode_fps_estimator_.Rate(now_ms).value_or(0);
+  stats_.interframe_delay_max_ms =
+      interframe_delay_max_moving_.Max(now_ms).value_or(-1);
+  stats_.freeze_count = video_quality_observer_->NumFreezes();
+  stats_.pause_count = video_quality_observer_->NumPauses();
+  stats_.total_freezes_duration_ms =
+      video_quality_observer_->TotalFreezesDurationMs();
+  stats_.total_pauses_duration_ms =
+      video_quality_observer_->TotalPausesDurationMs();
+  stats_.total_frames_duration_ms =
+      video_quality_observer_->TotalFramesDurationMs();
+  stats_.sum_squared_frame_durations =
+      video_quality_observer_->SumSquaredFrameDurationsSec();
+  stats_.content_type = last_content_type_;
+  stats_.timing_frame_info = timing_frame_info_counter_.Max(now_ms);
+  stats_.jitter_buffer_delay_seconds =
+      static_cast<double>(current_delay_counter_.Sum(1).value_or(0)) /
+      rtc::kNumMillisecsPerSec;
+  stats_.jitter_buffer_emitted_count = current_delay_counter_.NumSamples();
+  stats_.estimated_playout_ntp_timestamp_ms =
+      GetCurrentEstimatedPlayoutNtpTimestampMs(now_ms);
+  return stats_;
+}
+
+void ReceiveStatisticsProxy::OnIncomingPayloadType(int payload_type) {
+  rtc::CritScope lock(&crit_);
+  stats_.current_payload_type = payload_type;
+}
+
+void ReceiveStatisticsProxy::OnDecoderImplementationName(
+    const char* implementation_name) {
+  rtc::CritScope lock(&crit_);
+  stats_.decoder_implementation_name = implementation_name;
+}
+
+void ReceiveStatisticsProxy::OnFrameBufferTimingsUpdated(
+    int max_decode_ms,
+    int current_delay_ms,
+    int target_delay_ms,
+    int jitter_buffer_ms,
+    int min_playout_delay_ms,
+    int render_delay_ms) {
+  rtc::CritScope lock(&crit_);
+  stats_.max_decode_ms = max_decode_ms;
+  stats_.current_delay_ms = current_delay_ms;
+  stats_.target_delay_ms = target_delay_ms;
+  stats_.jitter_buffer_ms = jitter_buffer_ms;
+  stats_.min_playout_delay_ms = min_playout_delay_ms;
+  stats_.render_delay_ms = render_delay_ms;
+  jitter_buffer_delay_counter_.Add(jitter_buffer_ms);
+  target_delay_counter_.Add(target_delay_ms);
+  current_delay_counter_.Add(current_delay_ms);
+  // Network delay (rtt/2) + target_delay_ms (jitter delay + decode time +
+  // render delay).
+  delay_counter_.Add(target_delay_ms + avg_rtt_ms_ / 2);
+}
+
+void ReceiveStatisticsProxy::OnUniqueFramesCounted(int num_unique_frames) {
+  rtc::CritScope lock(&crit_);
+  num_unique_frames_.emplace(num_unique_frames);
+}
+
+void ReceiveStatisticsProxy::OnTimingFrameInfoUpdated(
+    const TimingFrameInfo& info) {
+  rtc::CritScope lock(&crit_);
+  if (info.flags != VideoSendTiming::kInvalid) {
+    int64_t now_ms = clock_->TimeInMilliseconds();
+    timing_frame_info_counter_.Add(info, now_ms);
+  }
+
+  // Measure initial decoding latency between the first frame arriving and the
+  // first frame being decoded.
+  if (!first_frame_received_time_ms_.has_value()) {
+    first_frame_received_time_ms_ = info.receive_finish_ms;
+  }
+  if (stats_.first_frame_received_to_decoded_ms == -1 &&
+      first_decoded_frame_time_ms_) {
+    stats_.first_frame_received_to_decoded_ms =
+        *first_decoded_frame_time_ms_ - *first_frame_received_time_ms_;
+  }
+}
+
+void ReceiveStatisticsProxy::RtcpPacketTypesCounterUpdated(
+    uint32_t ssrc,
+    const RtcpPacketTypeCounter& packet_counter) {
+  rtc::CritScope lock(&crit_);
+  if (stats_.ssrc != ssrc)
+    return;
+  stats_.rtcp_packet_type_counts = packet_counter;
+}
+
+void ReceiveStatisticsProxy::OnCname(uint32_t ssrc, absl::string_view cname) {
+  rtc::CritScope lock(&crit_);
+  // TODO(pbos): Handle both local and remote ssrcs here and RTC_DCHECK that we
+  // receive stats from one of them.
+  if (stats_.ssrc != ssrc)
+    return;
+  stats_.c_name = std::string(cname);
+}
+
+void ReceiveStatisticsProxy::OnDecodedFrame(const VideoFrame& frame,
+                                            absl::optional<uint8_t> qp,
+                                            int32_t decode_time_ms,
+                                            VideoContentType content_type) {
+  rtc::CritScope lock(&crit_);
+
+  uint64_t now_ms = clock_->TimeInMilliseconds();
+
+  if (videocontenttypehelpers::IsScreenshare(content_type) !=
+      videocontenttypehelpers::IsScreenshare(last_content_type_)) {
+    // Reset the quality observer if content type is switched. But first report
+    // stats for the previous part of the call.
+    video_quality_observer_->UpdateHistograms();
+    video_quality_observer_.reset(new VideoQualityObserver(content_type));
+  }
+
+  video_quality_observer_->OnDecodedFrame(frame, qp, last_codec_type_);
+
+  ContentSpecificStats* content_specific_stats =
+      &content_specific_stats_[content_type];
+  ++stats_.frames_decoded;
+  if (qp) {
+    if (!stats_.qp_sum) {
+      if (stats_.frames_decoded != 1) {
+        RTC_LOG(LS_WARNING)
+            << "Frames decoded was not 1 when first qp value was received.";
+      }
+      stats_.qp_sum = 0;
+    }
+    *stats_.qp_sum += *qp;
+    content_specific_stats->qp_counter.Add(*qp);
+  } else if (stats_.qp_sum) {
+    RTC_LOG(LS_WARNING)
+        << "QP sum was already set and no QP was given for a frame.";
+    stats_.qp_sum.reset();
+  }
+  decode_time_counter_.Add(decode_time_ms);
+  stats_.decode_ms = decode_time_ms;
+  stats_.total_decode_time_ms += decode_time_ms;
+  if (enable_decode_time_histograms_) {
+    UpdateDecodeTimeHistograms(frame.width(), frame.height(), decode_time_ms);
+  }
+
+  last_content_type_ = content_type;
+  decode_fps_estimator_.Update(1, now_ms);
+  if (last_decoded_frame_time_ms_) {
+    int64_t interframe_delay_ms = now_ms - *last_decoded_frame_time_ms_;
+    RTC_DCHECK_GE(interframe_delay_ms, 0);
+    double interframe_delay = interframe_delay_ms / 1000.0;
+    stats_.total_inter_frame_delay += interframe_delay;
+    stats_.total_squared_inter_frame_delay +=
+        interframe_delay * interframe_delay;
+    interframe_delay_max_moving_.Add(interframe_delay_ms, now_ms);
+    content_specific_stats->interframe_delay_counter.Add(interframe_delay_ms);
+    content_specific_stats->interframe_delay_percentiles.Add(
+        interframe_delay_ms);
+    content_specific_stats->flow_duration_ms += interframe_delay_ms;
+  }
+  if (stats_.frames_decoded == 1) {
+    first_decoded_frame_time_ms_.emplace(now_ms);
+  }
+  last_decoded_frame_time_ms_.emplace(now_ms);
+}
+
+void ReceiveStatisticsProxy::OnRenderedFrame(const VideoFrame& frame) {
+  int width = frame.width();
+  int height = frame.height();
+  RTC_DCHECK_GT(width, 0);
+  RTC_DCHECK_GT(height, 0);
+  int64_t now_ms = clock_->TimeInMilliseconds();
+  rtc::CritScope lock(&crit_);
+
+  video_quality_observer_->OnRenderedFrame(frame, now_ms);
+
+  ContentSpecificStats* content_specific_stats =
+      &content_specific_stats_[last_content_type_];
+  renders_fps_estimator_.Update(1, now_ms);
+  ++stats_.frames_rendered;
+  stats_.width = width;
+  stats_.height = height;
+  render_fps_tracker_.AddSamples(1);
+  render_pixel_tracker_.AddSamples(sqrt(width * height));
+  content_specific_stats->received_width.Add(width);
+  content_specific_stats->received_height.Add(height);
+
+  // Consider taking stats_.render_delay_ms into account.
+  const int64_t time_until_rendering_ms = frame.render_time_ms() - now_ms;
+  if (time_until_rendering_ms < 0) {
+    sum_missed_render_deadline_ms_ += -time_until_rendering_ms;
+    ++num_delayed_frames_rendered_;
+  }
+
+  if (frame.ntp_time_ms() > 0) {
+    int64_t delay_ms = clock_->CurrentNtpInMilliseconds() - frame.ntp_time_ms();
+    if (delay_ms >= 0) {
+      content_specific_stats->e2e_delay_counter.Add(delay_ms);
+    }
+  }
+  QualitySample();
+}
+
+void ReceiveStatisticsProxy::OnSyncOffsetUpdated(int64_t video_playout_ntp_ms,
+                                                 int64_t sync_offset_ms,
+                                                 double estimated_freq_khz) {
+  rtc::CritScope lock(&crit_);
+  sync_offset_counter_.Add(std::abs(sync_offset_ms));
+  stats_.sync_offset_ms = sync_offset_ms;
+  last_estimated_playout_ntp_timestamp_ms_ = video_playout_ntp_ms;
+  last_estimated_playout_time_ms_ = clock_->TimeInMilliseconds();
+
+  const double kMaxFreqKhz = 10000.0;
+  int offset_khz = kMaxFreqKhz;
+  // Should not be zero or negative. If so, report max.
+  if (estimated_freq_khz < kMaxFreqKhz && estimated_freq_khz > 0.0)
+    offset_khz = static_cast<int>(std::fabs(estimated_freq_khz - 90.0) + 0.5);
+
+  freq_offset_counter_.Add(offset_khz);
+}
+
+void ReceiveStatisticsProxy::OnCompleteFrame(bool is_keyframe,
+                                             size_t size_bytes,
+                                             VideoContentType content_type) {
+  rtc::CritScope lock(&crit_);
+  if (is_keyframe) {
+    ++stats_.frame_counts.key_frames;
+  } else {
+    ++stats_.frame_counts.delta_frames;
+  }
+
+  // Content type extension is set only for keyframes and should be propagated
+  // for all the following delta frames. Here we may receive frames out of order
+  // and miscategorise some delta frames near the layer switch.
+  // This may slightly offset calculated bitrate and keyframes permille metrics.
+  VideoContentType propagated_content_type =
+      is_keyframe ? content_type : last_content_type_;
+
+  ContentSpecificStats* content_specific_stats =
+      &content_specific_stats_[propagated_content_type];
+
+  content_specific_stats->total_media_bytes += size_bytes;
+  if (is_keyframe) {
+    ++content_specific_stats->frame_counts.key_frames;
+  } else {
+    ++content_specific_stats->frame_counts.delta_frames;
+  }
+
+  int64_t now_ms = clock_->TimeInMilliseconds();
+  frame_window_.insert(std::make_pair(now_ms, size_bytes));
+  UpdateFramerate(now_ms);
+}
+
+void ReceiveStatisticsProxy::OnDroppedFrames(uint32_t frames_dropped) {
+  rtc::CritScope lock(&crit_);
+  stats_.frames_dropped += frames_dropped;
+}
+
+void ReceiveStatisticsProxy::OnPreDecode(VideoCodecType codec_type, int qp) {
+  RTC_DCHECK_RUN_ON(&decode_thread_);
+  rtc::CritScope lock(&crit_);
+  last_codec_type_ = codec_type;
+  if (last_codec_type_ == kVideoCodecVP8 && qp != -1) {
+    qp_counters_.vp8.Add(qp);
+    qp_sample_.Add(qp);
+  }
+}
+
+void ReceiveStatisticsProxy::OnStreamInactive() {
+  // TODO(sprang): Figure out any other state that should be reset.
+
+  rtc::CritScope lock(&crit_);
+  // Don't report inter-frame delay if stream was paused.
+  last_decoded_frame_time_ms_.reset();
+  video_quality_observer_->OnStreamInactive();
+}
+
+void ReceiveStatisticsProxy::OnRttUpdate(int64_t avg_rtt_ms,
+                                         int64_t max_rtt_ms) {
+  rtc::CritScope lock(&crit_);
+  avg_rtt_ms_ = avg_rtt_ms;
+}
+
+void ReceiveStatisticsProxy::DecoderThreadStarting() {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+}
+
+void ReceiveStatisticsProxy::DecoderThreadStopped() {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  decode_thread_.Detach();
+}
+
+ReceiveStatisticsProxy::ContentSpecificStats::ContentSpecificStats()
+    : interframe_delay_percentiles(kMaxCommonInterframeDelayMs) {}
+
+ReceiveStatisticsProxy::ContentSpecificStats::~ContentSpecificStats() = default;
+
+void ReceiveStatisticsProxy::ContentSpecificStats::Add(
+    const ContentSpecificStats& other) {
+  e2e_delay_counter.Add(other.e2e_delay_counter);
+  interframe_delay_counter.Add(other.interframe_delay_counter);
+  flow_duration_ms += other.flow_duration_ms;
+  total_media_bytes += other.total_media_bytes;
+  received_height.Add(other.received_height);
+  received_width.Add(other.received_width);
+  qp_counter.Add(other.qp_counter);
+  frame_counts.key_frames += other.frame_counts.key_frames;
+  frame_counts.delta_frames += other.frame_counts.delta_frames;
+  interframe_delay_percentiles.Add(other.interframe_delay_percentiles);
+}
+
+}  // namespace internal
+}  // namespace webrtc