Add config to specify raw audio priority bitrate including overhead.

Bug: webrtc:10815
Change-Id: I6a498d6c6bcd4fe4ba6ccc4d6f407d686528d946
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/145333
Commit-Queue: Christoffer Rodbro <crodbro@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28590}
diff --git a/rtc_base/experiments/audio_allocation_settings.cc b/rtc_base/experiments/audio_allocation_settings.cc
index 034bcbb..dff1aae 100644
--- a/rtc_base/experiments/audio_allocation_settings.cc
+++ b/rtc_base/experiments/audio_allocation_settings.cc
@@ -9,6 +9,7 @@
  */
 #include "rtc_base/experiments/audio_allocation_settings.h"
 
+#include "rtc_base/logging.h"
 #include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
@@ -29,10 +30,11 @@
       min_bitrate_("min"),
       max_bitrate_("max"),
       priority_bitrate_("prio_rate", DataRate::Zero()),
+      priority_bitrate_raw_("prio_rate_raw"),
       bitrate_priority_("rate_prio") {
-  ParseFieldTrial(
-      {&min_bitrate_, &max_bitrate_, &priority_bitrate_, &bitrate_priority_},
-      field_trial::FindFullName("WebRTC-Audio-Allocation"));
+  ParseFieldTrial({&min_bitrate_, &max_bitrate_, &priority_bitrate_,
+                   &priority_bitrate_raw_, &bitrate_priority_},
+                  field_trial::FindFullName("WebRTC-Audio-Allocation"));
 
   // TODO(mflodman): Keep testing this and set proper values.
   // Note: This is an early experiment currently only supported by Opus.
@@ -40,6 +42,11 @@
     constexpr int kMaxPacketSizeMs = WEBRTC_OPUS_SUPPORT_120MS_PTIME ? 120 : 60;
     min_overhead_bps_ = kOverheadPerPacket * 8 * 1000 / kMaxPacketSizeMs;
   }
+  // priority_bitrate_raw will override priority_bitrate.
+  if (priority_bitrate_raw_ && !priority_bitrate_->IsZero()) {
+    RTC_LOG(LS_WARNING) << "'priority_bitrate' and '_raw' are mutually "
+                           "exclusive but both were configured.";
+  }
 }
 
 AudioAllocationSettings::~AudioAllocationSettings() {}
@@ -111,6 +118,9 @@
 }
 DataRate AudioAllocationSettings::DefaultPriorityBitrate() const {
   DataRate max_overhead = DataRate::Zero();
+  if (priority_bitrate_raw_) {
+    return *priority_bitrate_raw_;
+  }
   if (send_side_bwe_with_overhead_) {
     const TimeDelta kMinPacketDuration = TimeDelta::ms(20);
     max_overhead = DataSize::bytes(kOverheadPerPacket) / kMinPacketDuration;
diff --git a/rtc_base/experiments/audio_allocation_settings.h b/rtc_base/experiments/audio_allocation_settings.h
index 6c655b8..8c5259b 100644
--- a/rtc_base/experiments/audio_allocation_settings.h
+++ b/rtc_base/experiments/audio_allocation_settings.h
@@ -90,6 +90,9 @@
   FieldTrialOptional<DataRate> min_bitrate_;
   FieldTrialOptional<DataRate> max_bitrate_;
   FieldTrialParameter<DataRate> priority_bitrate_;
+  // By default the priority_bitrate is compensated for packet overhead.
+  // Use this flag to configure a raw value instead.
+  FieldTrialOptional<DataRate> priority_bitrate_raw_;
   FieldTrialOptional<double> bitrate_priority_;
 };
 }  // namespace webrtc