From a471e797bc6bb5d26375e4c56ff4aacbab08b8a9 Mon Sep 17 00:00:00 2001
From: Ying Wang <yinwa@webrtc.org>
Date: Mon, 26 Aug 2019 10:10:52 +0200
Subject: [PATCH] Make min video target bitrate configurable.
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Change-Id: I5adf1e675be2114b648878078a8f2e6808c390c7
Bug: webrtc:10915
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/150331
Commit-Queue: Ying Wang <yinwa@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28959}
---
 media/engine/constants.cc           |  1 +
 media/engine/constants.h            |  1 +
 media/engine/webrtc_video_engine.cc |  4 +++-
 media/engine/webrtc_video_engine.h  | 14 ++++++++++++++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/media/engine/constants.cc b/media/engine/constants.cc
index fb3ac698e6..e0cccba9f9 100644
--- a/media/engine/constants.cc
+++ b/media/engine/constants.cc
@@ -16,4 +16,5 @@ const int kMinVideoBitrateBps = 30000;
 const int kVideoMtu = 1200;
 const int kVideoRtpSendBufferSize = 65536;
 const int kVideoRtpRecvBufferSize = 262144;
+const char* kMinVideoBitrateExperiment = "WebRTC-Video-MinVideoBitrate";
 }  // namespace cricket
diff --git a/media/engine/constants.h b/media/engine/constants.h
index b136060546..e9ad369515 100644
--- a/media/engine/constants.h
+++ b/media/engine/constants.h
@@ -20,6 +20,7 @@ extern const int kVideoRtpRecvBufferSize;
 extern const char kH264CodecName[];
 
 extern const int kMinVideoBitrateBps;
+extern const char* kMinVideoBitrateExperiment;
 
 }  // namespace cricket
 
diff --git a/media/engine/webrtc_video_engine.cc b/media/engine/webrtc_video_engine.cc
index a3e48d9447..26357c6575 100644
--- a/media/engine/webrtc_video_engine.cc
+++ b/media/engine/webrtc_video_engine.cc
@@ -27,7 +27,6 @@
 #include "api/video_codecs/video_encoder.h"
 #include "api/video_codecs/video_encoder_factory.h"
 #include "call/call.h"
-#include "media/engine/constants.h"
 #include "media/engine/simulcast.h"
 #include "media/engine/webrtc_media_engine.h"
 #include "media/engine/webrtc_voice_engine.h"
@@ -329,6 +328,9 @@ absl::optional<int> GetFallbackMinBpsFromFieldTrial(
 }
 
 int GetMinVideoBitrateBps(webrtc::VideoCodecType type) {
+  if (webrtc::field_trial::IsEnabled(kMinVideoBitrateExperiment)) {
+    return MinVideoBitrateConfig().min_video_bitrate->bps();
+  }
   return GetFallbackMinBpsFromFieldTrial(type).value_or(kMinVideoBitrateBps);
 }
 }  // namespace
diff --git a/media/engine/webrtc_video_engine.h b/media/engine/webrtc_video_engine.h
index 8dd758f0eb..50467cd804 100644
--- a/media/engine/webrtc_video_engine.h
+++ b/media/engine/webrtc_video_engine.h
@@ -29,12 +29,15 @@
 #include "call/video_receive_stream.h"
 #include "call/video_send_stream.h"
 #include "media/base/media_engine.h"
+#include "media/engine/constants.h"
 #include "media/engine/unhandled_packets_buffer.h"
 #include "rtc_base/async_invoker.h"
 #include "rtc_base/critical_section.h"
+#include "rtc_base/experiments/field_trial_parser.h"
 #include "rtc_base/network_route.h"
 #include "rtc_base/thread_annotations.h"
 #include "rtc_base/thread_checker.h"
+#include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 class VideoDecoderFactory;
@@ -48,6 +51,17 @@ class Thread;
 
 namespace cricket {
 
+struct MinVideoBitrateConfig {
+  webrtc::FieldTrialParameter<webrtc::DataRate> min_video_bitrate;
+
+  MinVideoBitrateConfig()
+      : min_video_bitrate("br", webrtc::DataRate::KilobitsPerSec<30>()) {
+    webrtc::ParseFieldTrial(
+        {&min_video_bitrate},
+        webrtc::field_trial::FindFullName(kMinVideoBitrateExperiment));
+  }
+};
+
 class WebRtcVideoChannel;
 
 class UnsignalledSsrcHandler {