Change TWCC send interval to reduce overhead on low BW situations.

webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy_unittest.cc

 /*
  *  Copyright (c) 2015 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 <memory>
+#include <utility>
+
+#include "webrtc/test/gmock.h"
+#include "webrtc/test/gtest.h"
+
+#include "webrtc/modules/bitrate_controller/include/mock/mock_bitrate_controller.h"
 #include "webrtc/modules/pacing/packet_router.h"
 #include "webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "webrtc/system_wrappers/include/clock.h"
-#include "webrtc/test/gmock.h"
-#include "webrtc/test/gtest.h"
 
 using ::testing::_;
 using ::testing::InSequence;
 using ::testing::Invoke;
 using ::testing::Return;
 
 namespace webrtc {
 
 class MockPacketRouter : public PacketRouter {
  public:
   MOCK_METHOD1(SendFeedback, bool(rtcp::TransportFeedback* packet));
 };
 
 class RemoteEstimatorProxyTest : public ::testing::Test {
  public:
-  RemoteEstimatorProxyTest() : clock_(0), proxy_(&clock_, &router_) {}
+  RemoteEstimatorProxyTest()
+      : clock_(0), proxy_(&clock_, &router_, &bitrate_controller_) {}
 
  protected:
   void IncomingPacket(uint16_t seq, int64_t time_ms) {
     RTPHeader header;
     header.extension.hasTransportSequenceNumber = true;
     header.extension.transportSequenceNumber = seq;
     header.ssrc = kMediaSsrc;
     proxy_.IncomingPacket(time_ms, kDefaultPacketSize, header);
   }
 
   void Process() {
-    clock_.AdvanceTimeMilliseconds(
-        RemoteEstimatorProxy::kDefaultProcessIntervalMs);
+    clock_.AdvanceTimeMilliseconds(50);

[stefan-webrtc, 2016/10/26 14:45:16]

Why did you change this?

[michaelt, 2016/10/27 15:15:45]

Because there is no default process interval. The interval became with this CL
bit-rate depended. 

I replaced it with
RemoteEstimatorProxy::kMinSendIntervalMs

     proxy_.Process();
   }
 
   SimulatedClock clock_;
   testing::StrictMock<MockPacketRouter> router_;
+  testing::StrictMock<test::MockBitrateController> bitrate_controller_;
   RemoteEstimatorProxy proxy_;
 
   const size_t kDefaultPacketSize = 100;
   const uint32_t kMediaSsrc = 456;
   const uint16_t kBaseSeq = 10;
   const int64_t kBaseTimeMs = 123;
   const int64_t kMaxSmallDeltaMs =
       (rtcp::TransportFeedback::kDeltaScaleFactor * 0xFF) / 1000;
 };
 
@@ skipping 282 matching lines @@
         EXPECT_EQ(kBaseTimeMs - 1,
                   (packet->GetBaseTimeUs() + delta_vec[0]) / 1000);
         EXPECT_EQ(kTimeoutTimeMs - kBaseTimeMs, delta_vec[1] / 1000);
         EXPECT_EQ(1, delta_vec[2] / 1000);
         return true;
       }));
 
   Process();
 }
 
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsZeroBeforeFirstProcess) {
+  EXPECT_EQ(0, proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsMinIntervalOn300kbps) {
+  EXPECT_CALL(bitrate_controller_, AvailableBandwidth(testing::NotNull()))
+      .Times(1)
+      .WillOnce(Invoke([](uint32_t* bitrate) {
+        *bitrate = 300000;
+        return false;
+      }));
+
+  Process();
+  EXPECT_EQ(RemoteEstimatorProxy::kMinSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsMaxIntervalOn20kbps) {
+  EXPECT_CALL(bitrate_controller_, AvailableBandwidth(testing::NotNull()))
+      .Times(1)
+      .WillOnce(Invoke([](uint32_t* bitrate) {
+        *bitrate = 20000;
+        return false;
+      }));
+
+  Process();
+  EXPECT_EQ(RemoteEstimatorProxy::kMaxSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TwccReportsUse5PercentOfAvailableBandwidth) {
+  EXPECT_CALL(bitrate_controller_, AvailableBandwidth(testing::NotNull()))
+      .Times(1)
+      .WillOnce(Invoke([](uint32_t* bitrate) {
+        *bitrate = 80000;
+        return false;
+      }));
+  Process();
+  // 80kbps * 0.05 = TwccReportSize(52B * 8b/B) * 1000ms / SendInterval(104ms)
+  EXPECT_EQ(104, proxy_.TimeUntilNextProcess());
+}
+
 }  // namespace webrtc