Reimplemeted "Test and fix for huge bwe drop after alr state"

webrtc/modules/congestion_controller/bitrate_estimator.cc

Index: webrtc/modules/congestion_controller/bitrate_estimator.cc
diff --git a/webrtc/modules/congestion_controller/acknowledge_bitrate_estimator.cc b/webrtc/modules/congestion_controller/bitrate_estimator.cc
similarity index 75%
rename from webrtc/modules/congestion_controller/acknowledge_bitrate_estimator.cc
rename to webrtc/modules/congestion_controller/bitrate_estimator.cc
index 3fa3ac9995b0cbeb168ff2e6466ef6cdcfe49178..74df6d00e709dce511517ff938c3b87f67292a8b 100644
--- a/webrtc/modules/congestion_controller/acknowledge_bitrate_estimator.cc
+++ b/webrtc/modules/congestion_controller/bitrate_estimator.cc
@@ -8,7 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/congestion_controller/acknowledge_bitrate_estimator.h"
+#include "webrtc/modules/congestion_controller/bitrate_estimator.h"
 
 #include <cmath>
 
@@ -20,32 +20,18 @@ namespace webrtc {
 namespace {
 constexpr int kInitialRateWindowMs = 500;
 constexpr int kRateWindowMs = 150;
-
-bool IsInSendTimeHistory(const PacketFeedback& packet) {
-  return packet.send_time_ms >= 0;
-}
-
 }  // namespace
 
-AcknowledgedBitrateEstimator::AcknowledgedBitrateEstimator()
+BitrateEstimator::BitrateEstimator()
     : sum_(0),
       current_win_ms_(0),
       prev_time_ms_(-1),
       bitrate_estimate_(-1.0f),
       bitrate_estimate_var_(50.0f) {}
 
-void AcknowledgedBitrateEstimator::IncomingPacketFeedbackVector(
-    const std::vector<PacketFeedback>& packet_feedback_vector) {
-  RTC_DCHECK(std::is_sorted(packet_feedback_vector.begin(),
-                            packet_feedback_vector.end(),
-                            PacketFeedbackComparator()));
-  for (const auto& packet : packet_feedback_vector) {
-    if (IsInSendTimeHistory(packet))
-      Update(packet.arrival_time_ms, packet.payload_size);
-  }
-}
+BitrateEstimator::~BitrateEstimator() = default;
 
-void AcknowledgedBitrateEstimator::Update(int64_t now_ms, int bytes) {
+void BitrateEstimator::Update(int64_t now_ms, int bytes) {
   int rate_window_ms = kRateWindowMs;
   // We use a larger window at the beginning to get a more stable sample that
   // we can use to initialize the estimate.
@@ -78,9 +64,9 @@ void AcknowledgedBitrateEstimator::Update(int64_t now_ms, int bytes) {
                         bitrate_estimate_ * 1000);
 }
 
-float AcknowledgedBitrateEstimator::UpdateWindow(int64_t now_ms,
-                                                 int bytes,
-                                                 int rate_window_ms) {
+float BitrateEstimator::UpdateWindow(int64_t now_ms,
+                                     int bytes,
+                                     int rate_window_ms) {
   // Reset if time moves backwards.
   if (now_ms < prev_time_ms_) {
     prev_time_ms_ = -1;
@@ -106,10 +92,16 @@ float AcknowledgedBitrateEstimator::UpdateWindow(int64_t now_ms,
   return bitrate_sample;
 }
 
-rtc::Optional<uint32_t> AcknowledgedBitrateEstimator::bitrate_bps() const {
+rtc::Optional<uint32_t> BitrateEstimator::bitrate_bps() const {
   if (bitrate_estimate_ < 0.f)
     return rtc::Optional<uint32_t>();
   return rtc::Optional<uint32_t>(bitrate_estimate_ * 1000);
 }
 
+void BitrateEstimator::ExpectFastRateChange() {
+  // By setting the bitrate-estimate variance to a hight value we allow the

[holmer, 2017/07/07 07:53:07]

higher

[tschumi, 2017/07/07 09:07:59]

Done.

+  // bitrate to change fast for the next few samples.
+  bitrate_estimate_var_ = 200;

[terelius, 2017/07/07 08:01:19]

Why 200 compared to say, 50 or 20? Assuming that 200 is the correct value,
shouldn't we use that initially too? What if the previously estimated variance
is larger than 200?

[holmer, 2017/07/07 08:08:00]

Good point.

Maybe += 200 or similar?

[tschumi, 2017/07/07 09:07:59]

I have no strong verification for 200. I used the Integration test to verify it.
It seams hard to find a the right value :).

Its ok to me that its bigger than the initial value since the initialization of
the filter as a different behavior than the after its initialized. 

Will go for += 200. 

But i'm open to other ideas :)

+}
+
 }  // namespace webrtc