From 2e59a02dd49c122a0e848baaebb7a38faf20dec4 Mon Sep 17 00:00:00 2001
From: deadbeef <deadbeef@webrtc.org>
Date: Fri, 2 Dec 2016 11:29:33 -0800
Subject: [PATCH] Revert of Use different restrictions of acked bitrate lag
 depending on operating point. (patchset #3 id:40001 of
 https://codereview.webrtc.org/2542083003/ )

Reason for revert:
Appears to cause a regression to RampUpTest.SendSideAudioOnlyUpDownUpRtx:

https://build.chromium.org/p/client.webrtc.perf/builders/Android32%20Tests%20%28L%20Nexus6%29/builds/626

Original issue's description:
> Use different restrictions of acked bitrate lag depending on operating point.
>
> Before this the BWE was allowed to operate freely up to 100 kbps. This isn't a good idea for audio BWE.
>
> BUG=webrtc:5079
>
> Committed: https://crrev.com/5932149c9aeaa7679ad0bc3183047766832ca907
> Cr-Commit-Position: refs/heads/master@{#15389}

TBR=terelius@webrtc.org,stefan@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5079

Review-Url: https://codereview.webrtc.org/2547113002
Cr-Commit-Position: refs/heads/master@{#15394}
---
 .../aimd_rate_control.cc                      | 13 +++----
 .../aimd_rate_control_unittest.cc             | 38 -------------------
 2 files changed, 5 insertions(+), 46 deletions(-)

diff --git a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
index e0c9ccd3ba..685be422bf 100644
--- a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
+++ b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
@@ -228,14 +228,11 @@ uint32_t AimdRateControl::ChangeBitrate(uint32_t current_bitrate_bps,
     default:
       assert(false);
   }
-  // Don't change the bit rate if the send side is too far off.
-  // We allow a bit more lag at very low rates to not too easily get stuck if
-  // the encoder produces uneven outputs.
-  const uint32_t max_bitrate_bps =
-      static_cast<uint32_t>(1.5f * incoming_bitrate_bps) + 10000;
-  if (current_bitrate_bps > current_bitrate_bps_ &&
-      current_bitrate_bps > max_bitrate_bps) {
-    current_bitrate_bps = std::max(current_bitrate_bps_, max_bitrate_bps);
+  if ((incoming_bitrate_bps > 100000 || current_bitrate_bps > 150000) &&
+      current_bitrate_bps > 1.5 * incoming_bitrate_bps) {
+    // Allow changing the bit rate if we are operating at very low rates
+    // Don't change the bit rate if the send side is too far off
+    current_bitrate_bps = current_bitrate_bps_;
     time_last_bitrate_change_ = now_ms;
   }
   return current_bitrate_bps;
diff --git a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc
index 878a03c4f5..b36b16ddbf 100644
--- a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc
+++ b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc
@@ -89,42 +89,4 @@ TEST(AimdRateControlTest, GetLastBitrateDecrease) {
             states.aimd_rate_control->GetLastBitrateDecreaseBps());
 }
 
-TEST(AimdRateControlTest, BweLimitedByAckedBitrate) {
-  auto states = CreateAimdRateControlStates();
-  constexpr int kAckedBitrate = 10000;
-  InitBitrate(states, kAckedBitrate,
-              states.simulated_clock->TimeInMilliseconds());
-  while (states.simulated_clock->TimeInMilliseconds() - kClockInitialTime <
-         20000) {
-    UpdateRateControl(states, kBwNormal, kAckedBitrate,
-                      states.simulated_clock->TimeInMilliseconds());
-    states.simulated_clock->AdvanceTimeMilliseconds(100);
-  }
-  ASSERT_TRUE(states.aimd_rate_control->ValidEstimate());
-  EXPECT_EQ(static_cast<uint32_t>(1.5 * kAckedBitrate + 10000),
-            states.aimd_rate_control->LatestEstimate());
-}
-
-TEST(AimdRateControlTest, BweNotLimitedByDecreasingAckedBitrate) {
-  auto states = CreateAimdRateControlStates();
-  constexpr int kAckedBitrate = 100000;
-  InitBitrate(states, kAckedBitrate,
-              states.simulated_clock->TimeInMilliseconds());
-  while (states.simulated_clock->TimeInMilliseconds() - kClockInitialTime <
-         20000) {
-    UpdateRateControl(states, kBwNormal, kAckedBitrate,
-                      states.simulated_clock->TimeInMilliseconds());
-    states.simulated_clock->AdvanceTimeMilliseconds(100);
-  }
-  ASSERT_TRUE(states.aimd_rate_control->ValidEstimate());
-  // If the acked bitrate decreases the BWE shouldn't be reduced to 1.5x
-  // what's being acked, but also shouldn't get to increase more.
-  uint32_t prev_estimate = states.aimd_rate_control->LatestEstimate();
-  UpdateRateControl(states, kBwNormal, kAckedBitrate / 2,
-                    states.simulated_clock->TimeInMilliseconds());
-  uint32_t new_estimate = states.aimd_rate_control->LatestEstimate();
-  EXPECT_NEAR(new_estimate, static_cast<uint32_t>(1.5 * kAckedBitrate + 10000),
-              2000);
-  EXPECT_EQ(new_estimate, prev_estimate);
-}
 }  // namespace webrtc