Reduce send rate to 50% if overusing before we have an acknowledged bitrate.

webrtc/modules/congestion_controller/delay_based_bwe.cc

Index: webrtc/modules/congestion_controller/delay_based_bwe.cc
diff --git a/webrtc/modules/congestion_controller/delay_based_bwe.cc b/webrtc/modules/congestion_controller/delay_based_bwe.cc
index ad977313a809ee818a3c39a733295f2f4ac37967..5d2029856e4a6f4e8659c996581e4e14b1a526e4 100644
--- a/webrtc/modules/congestion_controller/delay_based_bwe.cc
+++ b/webrtc/modules/congestion_controller/delay_based_bwe.cc
@@ -201,6 +201,19 @@ DelayBasedBwe::Result DelayBasedBwe::MaybeUpdateEstimate(
         rate_control_.TimeToReduceFurther(now_ms, *acked_bitrate_bps)) {
       result.updated = UpdateEstimate(now_ms, acked_bitrate_bps, overusing,
                                       &result.target_bitrate_bps);
+    } else if (!acked_bitrate_bps && rate_control_.ValidEstimate() &&
+               rate_control_.TimeToReduceFurther(
+                   now_ms, rate_control_.LatestEstimate() / 2 - 1)) {
+      // Overusing before we have a measured acknowledged bitrate. We check
+      // TimeToReduceFurther (with a fake acknowledged bitrate) to avoid
+      // reducing too often

[stefan-webrtc, 2017/06/30 15:31:34]

End with .

[terelius, 2017/07/04 11:01:11]

Done.

+      // TODO(tschumim): Improve this and/or the acknowledged bitrate estimator
+      // so that we (almost) always have a bitrate estimate.
+      rate_control_.SetEstimate(rate_control_.LatestEstimate() / 2, now_ms);
+      result.updated = true;
+      result.probe = false;
+      result.target_bitrate_bps = rate_control_.LatestEstimate();
+      printf("Halving send rate because no acknowledged bitrate\n");

[stefan-webrtc, 2017/06/30 15:31:34]

Remove

[terelius, 2017/07/04 11:01:11]

Done. Thanks.

     }
   } else {
     if (probe_bitrate_bps) {