REMB changes, cloned from issue 722011.

BUG=

Review URL: https://webrtc-codereview.appspot.com/708012

git-svn-id: http://webrtc.googlecode.com/svn/trunk@2603 4adac7df-926f-26a2-2b94-8c16560cd09d

src/video_engine/vie_remb.cc

@@ -23,9 +23,10 @@ namespace webrtc {
 
 const int kRembSendIntervallMs = 1000;
 const int kRembTimeOutThresholdMs = 2000;
+const unsigned int kRembMinimumBitrateKbps = 50;
 
 // % threshold for if we should send a new REMB asap.
-const int kSendThresholdPercent = 97;
+const unsigned int kSendThresholdPercent = 97;
 
 VieRemb::VieRemb(ProcessThread* process_thread)
     : process_thread_(process_thread),
@@ -121,13 +122,18 @@ void VieRemb::OnReceiveBitrateChanged(unsigned int ssrc, unsigned int bitrate) {
         TickTime::MillisecondTimestamp(), bitrate);
   }
 
-  int new_remb_bitrate = last_send_bitrate_ -
+  // If we already have an estimate, check if the new total estimate is below
+  // kSendThresholdPercent of the previous estimate.
+  if (last_send_bitrate_ > 0) {
+    unsigned int new_remb_bitrate = last_send_bitrate_ -
         update_time_bitrates_[ssrc].second + bitrate;
+
     if (new_remb_bitrate < kSendThresholdPercent * last_send_bitrate_ / 100) {
-    // The new bitrate estimate is less than kSendThresholdPercent % of the last
+      // The new bitrate estimate is less than kSendThresholdPercent % of the
-    // report. Send a REMB asap.
+      // last report. Send a REMB asap.
       last_remb_time_ = TickTime::MillisecondTimestamp() - kRembSendIntervallMs;
     }
+  }
   update_time_bitrates_[ssrc] = std::make_pair(
       TickTime::MillisecondTimestamp(), bitrate);
 }
@@ -150,16 +156,6 @@ WebRtc_Word32 VieRemb::Process() {
 
   // Calculate total receive bitrate estimate.
   list_crit_->Enter();
-  int total_bitrate = 0;
-  int num_bitrates = update_time_bitrates_.size();
-
-  if (num_bitrates == 0) {
-    list_crit_->Leave();
-    return 0;
-  }
-
-  // TODO(mflodman) Use std::vector and change RTP module API.
-  unsigned int* ssrcs = new unsigned int[num_bitrates];
 
   // Remove any timed out estimates.
   SsrcTimeBitrate::iterator it = update_time_bitrates_.begin();
@@ -172,6 +168,17 @@ WebRtc_Word32 VieRemb::Process() {
     }
   }
 
+  int num_bitrates = update_time_bitrates_.size();
+
+  if (num_bitrates == 0) {
+    list_crit_->Leave();
+    return 0;
+  }
+
+  // TODO(mflodman) Use std::vector and change RTP module API.
+  unsigned int* ssrcs = new unsigned int[num_bitrates];
+
+  unsigned int total_bitrate = 0;
   int idx = 0;
   for (it = update_time_bitrates_.begin(); it != update_time_bitrates_.end();
       ++it, ++idx) {
@@ -187,6 +194,11 @@ WebRtc_Word32 VieRemb::Process() {
     sender = receive_modules_.front();
   }
   last_send_bitrate_ = total_bitrate;
+
+  // Never send a REMB lower than last_send_bitrate_.
+  if (last_send_bitrate_ < kRembMinimumBitrateKbps) {
+    last_send_bitrate_ = kRembMinimumBitrateKbps;
+  }
   list_crit_->Leave();
 
   if (sender) {

src/video_engine/vie_remb.h

@@ -75,7 +75,7 @@ class VieRemb : public RemoteBitrateObserver, public Module {
 
   // The last time a REMB was sent.
   int64_t last_remb_time_;
-  int last_send_bitrate_;
+  unsigned int last_send_bitrate_;
 
   // All RtpRtcp modules to include in the REMB packet.
   RtpModules receive_modules_;

src/video_engine/vie_remb_unittest.cc

@@ -88,6 +88,11 @@ TEST_F(ViERembTest, LowerEstimateToSendRemb) {
   vie_remb_->OnReceiveBitrateChanged(ssrc[0], bitrate_estimate);
   EXPECT_CALL(rtp, RemoteSSRC())
       .WillRepeatedly(Return(ssrc[0]));
+  // Call process to get a first estimate.
+  SleepMs(1010);
+  EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, 1, _))
+        .Times(1);
+  vie_remb_->Process();
 
   // Lower the estimate with more than 3% to trigger a call to SetREMBData right
   // away.
@@ -113,6 +118,12 @@ TEST_F(ViERembTest, VerifyCombinedBitrateEstimate) {
       .Times(AnyNumber())
       .WillRepeatedly(Return(ssrc[0]));
 
+  // Call process to get a first estimate.
+  EXPECT_CALL(rtp_0, SetREMBData(bitrate_estimate[0], 1, _))
+        .Times(1);
+  SleepMs(1010);
+  vie_remb_->Process();
+
   vie_remb_->OnReceiveBitrateChanged(ssrc[1], bitrate_estimate[1] + 100);
   EXPECT_CALL(rtp_1, RemoteSSRC())
       .Times(AnyNumber())
@@ -195,6 +206,13 @@ TEST_F(ViERembTest, ChangeSendRtpModule) {
       .Times(AnyNumber())
       .WillRepeatedly(Return(ssrc[1]));
 
+  // Call process to get a first estimate.
+  SleepMs(1010);
+  EXPECT_CALL(rtp_0, SetREMBData(bitrate_estimate[0] + bitrate_estimate[1], 2,
+                                 _))
+      .Times(1);
+  vie_remb_->Process();
+
   // Decrease estimate to trigger a REMB.
   bitrate_estimate[0] = bitrate_estimate[0] - 100;
   EXPECT_CALL(rtp_0, SetREMBData(bitrate_estimate[0] + bitrate_estimate[1], 2,
@@ -231,6 +249,12 @@ TEST_F(ViERembTest, OnlyOneRembForDoubleProcess) {
   EXPECT_CALL(rtp, RemoteSSRC())
       .WillRepeatedly(Return(ssrc[0]));
 
+  // Call process to get a first estimate.
+  SleepMs(1010);
+  EXPECT_CALL(rtp, SetREMBData(_, _, _))
+        .Times(1);
+  vie_remb_->Process();
+
   // Lower the estimate, should trigger a call to SetREMBData right away.
   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, 1, _))
@@ -277,6 +301,12 @@ TEST_F(ViERembTest, NoSendingRtpModule) {
   EXPECT_CALL(rtp, RemoteSSRC())
       .WillRepeatedly(Return(ssrc[0]));
 
+  // Call process to get a first estimate.
+  SleepMs(1010);
+  EXPECT_CALL(rtp, SetREMBData(_, _, _))
+      .Times(1);
+  vie_remb_->Process();
+
   // Lower the estimate to trigger a new packet REMB packet.
   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp, SetREMBData(_, _, _))