Add an experiment for stricter pacing and ALR probing.

webrtc/video/video_send_stream.cc

 /*
  *  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 "webrtc/video/video_send_stream.h"
@@ skipping 806 matching lines @@
       transport_overhead_bytes_per_packet_(0) {
   RTC_DCHECK_RUN_ON(worker_queue_);
   LOG(LS_INFO) << "VideoSendStreamInternal: " << config_->ToString();
   weak_ptr_ = weak_ptr_factory_.GetWeakPtr();
   module_process_thread_checker_.DetachFromThread();
 
   RTC_DCHECK(!config_->rtp.ssrcs.empty());
   RTC_DCHECK(call_stats_);
   RTC_DCHECK(transport_);
   RTC_DCHECK(transport_->send_side_cc());
-
+  RTC_CHECK(field_trial::FindFullName(
+                AlrDetector::kStrictPacingAndProbingExperimentName)
+                .empty() ||
+            field_trial::FindFullName(
+                AlrDetector::kScreenshareProbingBweExperimentName)
+                .empty());
+  rtc::Optional<AlrDetector::AlrExperimentSettings> alr_settings;
   if (content_type == VideoEncoderConfig::ContentType::kScreen) {
-    rtc::Optional<AlrDetector::AlrExperimentSettings> alr_settings =
-        AlrDetector::ParseAlrSettingsFromFieldTrial();
-    if (alr_settings) {
-      transport->send_side_cc()->EnablePeriodicAlrProbing(true);
-      transport->send_side_cc()->pacer()->SetPacingFactor(
-          alr_settings->pacing_factor);
-      transport->send_side_cc()->pacer()->SetQueueTimeLimit(
-          alr_settings->max_paced_queue_time);
-    }
+    alr_settings = AlrDetector::ParseAlrSettingsFromFieldTrial(
+        AlrDetector::kScreenshareProbingBweExperimentName);
+  } else {
+    alr_settings = AlrDetector::ParseAlrSettingsFromFieldTrial(
+        AlrDetector::kStrictPacingAndProbingExperimentName);
+  }
+  if (alr_settings) {
+    transport->send_side_cc()->EnablePeriodicAlrProbing(true);
+    transport->send_side_cc()->pacer()->SetPacingFactor(
+        alr_settings->pacing_factor);
+    transport->send_side_cc()->pacer()->SetQueueTimeLimit(
+        alr_settings->max_paced_queue_time);
   }
 
   if (config_->periodic_alr_bandwidth_probing) {
     transport->send_side_cc()->EnablePeriodicAlrProbing(true);
   }
 
   // RTP/RTCP initialization.
 
   // We add the highest spatial layer first to ensure it'll be prioritized
   // when sending padding, with the hope that the packet rate will be smaller,
@@ skipping 522 matching lines @@
       std::min(config_->rtp.max_packet_size,
                kPathMTU - transport_overhead_bytes_per_packet_);
 
   for (RtpRtcp* rtp_rtcp : rtp_rtcp_modules_) {
     rtp_rtcp->SetMaxRtpPacketSize(rtp_packet_size);
   }
 }
 
 }  // namespace internal
 }  // namespace webrtc