Piggybacking simulcast id and ALR experiment id into video content type extension.

webrtc/video/receive_statistics_proxy.cc

Index: webrtc/video/receive_statistics_proxy.cc
diff --git a/webrtc/video/receive_statistics_proxy.cc b/webrtc/video/receive_statistics_proxy.cc
index 38e91d7a8ef2a09bcc476add136152aae4475cba..f23c656102311e48f83dd0303d8571f98f5dbbcf 100644
--- a/webrtc/video/receive_statistics_proxy.cc
+++ b/webrtc/video/receive_statistics_proxy.cc
@@ -12,8 +12,10 @@
 
 #include <algorithm>
 #include <cmath>
+#include <sstream>
 #include <utility>
 
+#include "webrtc/modules/pacing/alr_detector.h"
 #include "webrtc/modules/video_coding/include/video_codec_interface.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/logging.h"
@@ -46,6 +48,24 @@ const int kHighVarianceThreshold = 2;
 
 // How large window we use to calculate the framerate/bitrate.
 const int kRateStatisticsWindowSizeMs = 1000;
+
+std::string UmaPrefixForContentType(VideoContentType content_type) {
+  std::stringstream ss;
+  ss << "WebRTC.Video";
+  if (content_type.IsScreenshare()) {
+    ss << ".Screenshare";
+  }
+  return ss.str();
+}
+
+std::string UmaSuffixForContentType(VideoContentType content_type) {
+  std::stringstream ss;
+  int simulcast_id = content_type.GetSimulcastId();
+  if (simulcast_id > 0) {
+    ss << ".S" << simulcast_id - 1;
+  }
+  return ss.str();
+}
 }  // namespace
 
 ReceiveStatisticsProxy::ReceiveStatisticsProxy(
@@ -75,10 +95,6 @@ ReceiveStatisticsProxy::ReceiveStatisticsProxy(
       render_fps_tracker_(100, 10u),
       render_pixel_tracker_(100, 10u),
       total_byte_tracker_(100, 10u),  // bucket_interval_ms, bucket_count
-      e2e_delay_max_ms_video_(-1),
-      e2e_delay_max_ms_screenshare_(-1),
-      interframe_delay_max_ms_video_(-1),
-      interframe_delay_max_ms_screenshare_(-1),
       freq_offset_counter_(clock, nullptr, kFreqOffsetProcessIntervalMs),
       first_report_block_time_ms_(-1),
       avg_rtt_ms_(0),
@@ -96,6 +112,22 @@ ReceiveStatisticsProxy::~ReceiveStatisticsProxy() {
 }
 
 void ReceiveStatisticsProxy::UpdateHistograms() {
+  // Set synthetic field trial based on received experiment id.
+  // Since experiment is set at the send side and is not changed during the
+  // call, any received content type may be used.
+  int experiment_id = last_content_type_.GetExperimentId();
+  if (experiment_id != 0) {  // 0 means no experiment is active.
+    std::stringstream group_name;
+    group_name << "Group-" << experiment_id - 1;
+    field_trial::RegisterSyntheticFieldTrial(
+        AlrDetector::kScreenshareProbingBweExperimentNameOnReceiveSide,
+        group_name.str());
+  } else {
+    // No experiment group specified.
+    field_trial::RegisterSyntheticFieldTrial(
+        AlrDetector::kScreenshareProbingBweExperimentNameOnReceiveSide, "");
+  }
+
   RTC_HISTOGRAM_COUNTS_100000(
       "WebRTC.Video.ReceiveStreamLifetimeInSeconds",
       (clock_->TimeInMilliseconds() - start_ms_) / 1000);
@@ -186,62 +218,52 @@ void ReceiveStatisticsProxy::UpdateHistograms() {
   if (delay_ms != -1)
     RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.OnewayDelayInMs", delay_ms);
 
-  int e2e_delay_ms_video = e2e_delay_counter_video_.Avg(kMinRequiredSamples);
-  if (e2e_delay_ms_video != -1) {
-    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.EndToEndDelayInMs",
-                               e2e_delay_ms_video);
-    LOG(LS_INFO) << "WebRTC.Video.EndToEndDelayInMs " << e2e_delay_ms_video;
-  }
-
-  int e2e_delay_ms_screenshare =
-      e2e_delay_counter_screenshare_.Avg(kMinRequiredSamples);
-  if (e2e_delay_ms_screenshare != -1) {
-    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.Screenshare.EndToEndDelayInMs",
-                               e2e_delay_ms_screenshare);
-  }
-
-  int e2e_delay_max_ms_video = e2e_delay_max_ms_video_;
-  if (e2e_delay_max_ms_video != -1) {
-    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Video.EndToEndDelayMaxInMs",
-                                e2e_delay_max_ms_video);
-  }
-
-  int e2e_delay_max_ms_screenshare = e2e_delay_max_ms_screenshare_;
-  if (e2e_delay_max_ms_screenshare != -1) {
-    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Video.Screenshare.EndToEndDelayMaxInMs",
-                                e2e_delay_max_ms_screenshare);
-  }
-
-  int interframe_delay_ms_screenshare =
-      interframe_delay_counter_screenshare_.Avg(kMinRequiredSamples);
-  if (interframe_delay_ms_screenshare != -1) {
-    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.Screenshare.InterframeDelayInMs",
-                               interframe_delay_ms_screenshare);
-  }
-
-  int interframe_delay_ms_video =
-      interframe_delay_counter_video_.Avg(kMinRequiredSamples);
-  if (interframe_delay_ms_video != -1) {
-    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.InterframeDelayInMs",
-                               interframe_delay_ms_video);
-  }
-
-  int interframe_delay_max_ms_screenshare =
-      interframe_delay_max_ms_screenshare_;
-  if (interframe_delay_max_ms_screenshare != -1) {
-    RTC_HISTOGRAM_COUNTS_10000(
-        "WebRTC.Video.Screenshare.InterframeDelayMaxInMs",
-        interframe_delay_ms_screenshare);
-  }
-
-  int interframe_delay_max_ms_video = interframe_delay_max_ms_video_;
-  if (interframe_delay_max_ms_video != -1) {
-    RTC_HISTOGRAM_COUNTS_10000(
-        "WebRTC.Video.InterframeDelayMaxInMs",
-        interframe_delay_ms_video);
+  for (auto it : content_specific_stats_) {
+    auto content_type = it.first;
+    auto stats = it.second;
+    std::string uma_prefix = UmaPrefixForContentType(content_type);
+    std::string uma_suffix = UmaSuffixForContentType(content_type);
+    // The same line of code can't report different histograms because of how
+    // macro is done. Additional index needed to be different for all different
+    // names. Since experiment can't change during call, we could report 4*2
+    // different content types (4 simulcast_ids x 2 content types).
+    // Conveniently all of these are stored in 3 lower bits in VideoContentType.
+    int idx = content_type.content_type & 0x07;
+    int e2e_delay_ms = stats.e2e_delay_counter.Avg(kMinRequiredSamples);
+    if (e2e_delay_ms != -1) {
+      RTC_HISTOGRAMS_COUNTS_10000(
+          idx, uma_prefix + "EndToEndDelayInMs" + uma_suffix, e2e_delay_ms);
+      LOG(LS_INFO) << uma_prefix << "EndToEndDelayInMs " << uma_suffix
+                   << e2e_delay_ms;
+    }
+    int e2e_delay_max_ms = stats.e2e_delay_counter.Max();
+
+    if (e2e_delay_max_ms != -1) {
+      RTC_HISTOGRAMS_COUNTS_100000(
+          idx, uma_prefix + "EndToEndDelayMaxInMs" + uma_suffix,
+          e2e_delay_max_ms);
+      LOG(LS_INFO) << uma_prefix << "EndToEndDelayMaxInMs" << uma_suffix << " "
+                   << e2e_delay_max_ms;
+    }
+    int interframe_delay_ms =
+        stats.interframe_delay_counter.Avg(kMinRequiredSamples);
+    if (interframe_delay_ms != -1) {
+      RTC_HISTOGRAMS_COUNTS_10000(
+          idx, uma_prefix + "InterframeDelayInMs" + uma_suffix,
+          interframe_delay_ms);
+      LOG(LS_INFO) << uma_prefix << "InterframeDelayInMs" << uma_suffix << " "
+                   << interframe_delay_ms;
+    }
+    int interframe_delay_max_ms = stats.interframe_delay_counter.Max();
+    if (interframe_delay_max_ms != -1) {
+      RTC_HISTOGRAMS_COUNTS_10000(
+          idx, uma_prefix + "InterframeDelayMaxInMs" + uma_suffix,
+          interframe_delay_max_ms);
+      LOG(LS_INFO) << uma_prefix << "InterframeDelayMaxInMs" << uma_suffix
+                   << " " << interframe_delay_max_ms;
+    }
   }
 
-
   StreamDataCounters rtp = stats_.rtp_stats;
   StreamDataCounters rtx;
   for (auto it : rtx_stats_)
@@ -574,17 +596,13 @@ void ReceiveStatisticsProxy::OnDecodedFrame(rtc::Optional<uint8_t> qp,
     int64_t interframe_delay_ms = now - *last_decoded_frame_time_ms_;
     RTC_DCHECK_GE(interframe_delay_ms, 0);
     stats_.interframe_delay_sum_ms += interframe_delay_ms;
-    if (last_content_type_ == VideoContentType::SCREENSHARE) {
-      interframe_delay_counter_screenshare_.Add(interframe_delay_ms);
-      if (interframe_delay_max_ms_screenshare_ < interframe_delay_ms) {
-        interframe_delay_max_ms_screenshare_ = interframe_delay_ms;
-      }
-    } else {
-      interframe_delay_counter_video_.Add(interframe_delay_ms);
-      if (interframe_delay_max_ms_video_ < interframe_delay_ms) {
-        interframe_delay_max_ms_video_ = interframe_delay_ms;
-      }
+    auto it = content_specific_stats_.find(last_content_type_);
+    if (it == content_specific_stats_.end()) {
+      content_specific_stats_[last_content_type_] = ContentSpecificStats();
+      it = content_specific_stats_.find(last_content_type_);
     }
+    ContentSpecificStats* stats = &it->second;
+    stats->interframe_delay_counter.Add(interframe_delay_ms);
   }
   last_decoded_frame_time_ms_.emplace(now);
 }
@@ -609,14 +627,13 @@ void ReceiveStatisticsProxy::OnRenderedFrame(const VideoFrame& frame) {
   if (frame.ntp_time_ms() > 0) {
     int64_t delay_ms = clock_->CurrentNtpInMilliseconds() - frame.ntp_time_ms();
     if (delay_ms >= 0) {
-      if (last_content_type_ == VideoContentType::SCREENSHARE) {
-        e2e_delay_max_ms_screenshare_ =
-            std::max(delay_ms, e2e_delay_max_ms_screenshare_);
-        e2e_delay_counter_screenshare_.Add(delay_ms);
-      } else {
-        e2e_delay_max_ms_video_ = std::max(delay_ms, e2e_delay_max_ms_video_);
-        e2e_delay_counter_video_.Add(delay_ms);
+      auto it = content_specific_stats_.find(last_content_type_);
+      if (it == content_specific_stats_.end()) {
+        content_specific_stats_[last_content_type_] = ContentSpecificStats();
+        it = content_specific_stats_.find(last_content_type_);
       }
+      ContentSpecificStats* stats = &it->second;
+      stats->e2e_delay_counter.Add(delay_ms);
     }
   }
 
@@ -687,6 +704,9 @@ void ReceiveStatisticsProxy::OnPreDecode(
 void ReceiveStatisticsProxy::SampleCounter::Add(int sample) {
   sum += sample;
   ++num_samples;
+  if (!max || *max < sample) {
+    max.emplace(sample);
+  }
 }
 
 int ReceiveStatisticsProxy::SampleCounter::Avg(
@@ -696,9 +716,18 @@ int ReceiveStatisticsProxy::SampleCounter::Avg(
   return static_cast<int>(sum / num_samples);
 }
 
+int ReceiveStatisticsProxy::SampleCounter::Max() const {
+  if (!max) {
+    return -1;
+  } else {
+    return static_cast<int>(*max);
+  }
+}
+
 void ReceiveStatisticsProxy::SampleCounter::Reset() {
   num_samples = 0;
   sum = 0;
+  max.reset();
 }
 
 void ReceiveStatisticsProxy::OnRttUpdate(int64_t avg_rtt_ms,