diff --git a/modules/audio_coding/neteq/delay_manager.cc b/modules/audio_coding/neteq/delay_manager.cc
index dd0d759..3a74896 100644
--- a/modules/audio_coding/neteq/delay_manager.cc
+++ b/modules/audio_coding/neteq/delay_manager.cc
@@ -72,6 +72,7 @@
 struct DelayHistogramConfig {
   int quantile = 1020054733;  // 0.95 in Q30.
   int forget_factor = 32745;  // 0.9993 in Q15.
+  absl::optional<double> start_forget_weight;
 };
 
 absl::optional<DelayHistogramConfig> GetDelayHistogramConfig() {
@@ -85,16 +86,22 @@
     DelayHistogramConfig config;
     double percentile = -1.0;
     double forget_factor = -1.0;
-    if (sscanf(field_trial_string.c_str(), "Enabled-%lf-%lf", &percentile,
-               &forget_factor) == 2 &&
+    double start_forget_weight = -1.0;
+    if (sscanf(field_trial_string.c_str(), "Enabled-%lf-%lf-%lf", &percentile,
+               &forget_factor, &start_forget_weight) >= 2 &&
         percentile >= 0.0 && percentile <= 100.0 && forget_factor >= 0.0 &&
         forget_factor <= 1.0) {
       config.quantile = PercentileToQuantile(percentile);
       config.forget_factor = (1 << 15) * forget_factor;
+      if (start_forget_weight >= 1) {
+        config.start_forget_weight = start_forget_weight;
+      }
     }
     RTC_LOG(LS_INFO) << "Delay histogram config:"
                      << " quantile=" << config.quantile
-                     << " forget_factor=" << config.forget_factor;
+                     << " forget_factor=" << config.forget_factor
+                     << " start_forget_weight="
+                     << config.start_forget_weight.value_or(0);
     return absl::make_optional(config);
   }
   return absl::nullopt;
@@ -182,8 +189,8 @@
   if (delay_histogram_config) {
     DelayHistogramConfig config = delay_histogram_config.value();
     quantile = config.quantile;
-    histogram =
-        absl::make_unique<Histogram>(kDelayBuckets, config.forget_factor);
+    histogram = absl::make_unique<Histogram>(
+        kDelayBuckets, config.forget_factor, config.start_forget_weight);
     mode = RELATIVE_ARRIVAL_DELAY;
   } else {
     quantile = GetForcedLimitProbability().value_or(kLimitProbability);
diff --git a/modules/audio_coding/neteq/delay_manager.h b/modules/audio_coding/neteq/delay_manager.h
index 279e608..3075bfb 100644
--- a/modules/audio_coding/neteq/delay_manager.h
+++ b/modules/audio_coding/neteq/delay_manager.h
@@ -140,7 +140,7 @@
   // These accessors are only intended for testing purposes.
   HistogramMode histogram_mode() const { return histogram_mode_; }
   int histogram_quantile() const { return histogram_quantile_; }
-  int histogram_forget_factor() const { return histogram_->forget_factor(); }
+  Histogram* histogram() const { return histogram_.get(); }
 
  private:
   // Provides value which minimum delay can't exceed based on current buffer
diff --git a/modules/audio_coding/neteq/delay_manager_unittest.cc b/modules/audio_coding/neteq/delay_manager_unittest.cc
index eb1fabc..1004261 100644
--- a/modules/audio_coding/neteq/delay_manager_unittest.cc
+++ b/modules/audio_coding/neteq/delay_manager_unittest.cc
@@ -643,7 +643,10 @@
     EXPECT_EQ(DelayManager::HistogramMode::RELATIVE_ARRIVAL_DELAY,
               dm_->histogram_mode());
     EXPECT_EQ(1030792151, dm_->histogram_quantile());  // 0.96 in Q30.
-    EXPECT_EQ(32702, dm_->histogram_forget_factor());  // 0.998 in Q15.
+    EXPECT_EQ(
+        32702,
+        dm_->histogram()->base_forget_factor_for_testing());  // 0.998 in Q15.
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
   }
   {
     test::ScopedFieldTrials field_trial(
@@ -652,7 +655,10 @@
     EXPECT_EQ(DelayManager::HistogramMode::RELATIVE_ARRIVAL_DELAY,
               dm_->histogram_mode());
     EXPECT_EQ(1046898278, dm_->histogram_quantile());  // 0.975 in Q30.
-    EXPECT_EQ(32702, dm_->histogram_forget_factor());  // 0.998 in Q15.
+    EXPECT_EQ(
+        32702,
+        dm_->histogram()->base_forget_factor_for_testing());  // 0.998 in Q15.
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
   }
   {
     // NetEqDelayHistogram should take precedence over
@@ -664,7 +670,10 @@
     EXPECT_EQ(DelayManager::HistogramMode::RELATIVE_ARRIVAL_DELAY,
               dm_->histogram_mode());
     EXPECT_EQ(1030792151, dm_->histogram_quantile());  // 0.96 in Q30.
-    EXPECT_EQ(32702, dm_->histogram_forget_factor());  // 0.998 in Q15.
+    EXPECT_EQ(
+        32702,
+        dm_->histogram()->base_forget_factor_for_testing());  // 0.998 in Q15.
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
   }
   {
     // Invalid parameters.
@@ -675,7 +684,10 @@
               dm_->histogram_mode());
     EXPECT_EQ(kDefaultHistogramQuantile,
               dm_->histogram_quantile());                      // 0.95 in Q30.
-    EXPECT_EQ(kForgetFactor, dm_->histogram_forget_factor());  // 0.9993 in Q15.
+    EXPECT_EQ(
+        kForgetFactor,
+        dm_->histogram()->base_forget_factor_for_testing());  // 0.9993 in Q15.
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
   }
   {
     test::ScopedFieldTrials field_trial(
@@ -685,7 +697,30 @@
               dm_->histogram_mode());
     EXPECT_EQ(kDefaultHistogramQuantile,
               dm_->histogram_quantile());                      // 0.95 in Q30.
-    EXPECT_EQ(kForgetFactor, dm_->histogram_forget_factor());  // 0.9993 in Q15.
+    EXPECT_EQ(
+        kForgetFactor,
+        dm_->histogram()->base_forget_factor_for_testing());  // 0.9993 in Q15.
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
+  }
+
+  // Test parameter for new call start adaptation.
+  {
+    test::ScopedFieldTrials field_trial(
+        "WebRTC-Audio-NetEqDelayHistogram/Enabled-96-0.998-1/");
+    RecreateDelayManager();
+    EXPECT_EQ(dm_->histogram()->start_forget_weight_for_testing().value(), 1.0);
+  }
+  {
+    test::ScopedFieldTrials field_trial(
+        "WebRTC-Audio-NetEqDelayHistogram/Enabled-96-0.998-1.5/");
+    RecreateDelayManager();
+    EXPECT_EQ(dm_->histogram()->start_forget_weight_for_testing().value(), 1.5);
+  }
+  {
+    test::ScopedFieldTrials field_trial(
+        "WebRTC-Audio-NetEqDelayHistogram/Enabled-96-0.998-0.5/");
+    RecreateDelayManager();
+    EXPECT_FALSE(dm_->histogram()->start_forget_weight_for_testing());
   }
 }
 
diff --git a/modules/audio_coding/neteq/histogram.cc b/modules/audio_coding/neteq/histogram.cc
index 2f72653..fc0801e 100644
--- a/modules/audio_coding/neteq/histogram.cc
+++ b/modules/audio_coding/neteq/histogram.cc
@@ -12,23 +12,30 @@
 #include <cstdlib>
 #include <numeric>
 
+#include "absl/types/optional.h"
 #include "modules/audio_coding/neteq/histogram.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/numerics/safe_conversions.h"
 
 namespace webrtc {
 
-Histogram::Histogram(size_t num_buckets, int forget_factor)
+Histogram::Histogram(size_t num_buckets,
+                     int forget_factor,
+                     absl::optional<double> start_forget_weight)
     : buckets_(num_buckets, 0),
       forget_factor_(0),
-      base_forget_factor_(forget_factor) {}
+      base_forget_factor_(forget_factor),
+      add_count_(0),
+      start_forget_weight_(start_forget_weight) {
+  RTC_DCHECK_LT(base_forget_factor_, 1 << 15);
+}
 
 Histogram::~Histogram() {}
 
 // Each element in the vector is first multiplied by the forgetting factor
 // |forget_factor_|. Then the vector element indicated by |iat_packets| is then
 // increased (additive) by 1 - |forget_factor_|. This way, the probability of
-// |iat_packets| is slightly increased, while the sum of the histogram remains
+// |value| is slightly increased, while the sum of the histogram remains
 // constant (=1).
 // Due to inaccuracies in the fixed-point arithmetic, the histogram may no
 // longer sum up to 1 (in Q30) after the update. To correct this, a correction
@@ -37,7 +44,7 @@
 // The forgetting factor |forget_factor_| is also updated. When the DelayManager
 // is reset, the factor is set to 0 to facilitate rapid convergence in the
 // beginning. With each update of the histogram, the factor is increased towards
-// the steady-state value |kIatFactor_|.
+// the steady-state value |base_forget_factor_|.
 void Histogram::Add(int value) {
   RTC_DCHECK(value >= 0);
   RTC_DCHECK(value < static_cast<int>(buckets_.size()));
@@ -72,9 +79,28 @@
   }
   RTC_DCHECK(vector_sum == 0);  // Verify that the above is correct.
 
+  ++add_count_;
+
   // Update |forget_factor_| (changes only during the first seconds after a
   // reset). The factor converges to |base_forget_factor_|.
-  forget_factor_ += (base_forget_factor_ - forget_factor_ + 3) >> 2;
+  if (start_forget_weight_) {
+    if (forget_factor_ != base_forget_factor_) {
+      int old_forget_factor = forget_factor_;
+      int forget_factor =
+          (1 << 15) * (1 - start_forget_weight_.value() / (add_count_ + 1));
+      forget_factor_ =
+          std::max(0, std::min(base_forget_factor_, forget_factor));
+      // The histogram is updated recursively by forgetting the old histogram
+      // with |forget_factor_| and adding a new sample multiplied by |1 -
+      // forget_factor_|. We need to make sure that the effective weight on the
+      // new sample is no smaller than those on the old samples, i.e., to
+      // satisfy the following DCHECK.
+      RTC_DCHECK_GE((1 << 15) - forget_factor_,
+                    ((1 << 15) - old_forget_factor) * forget_factor_ >> 15);
+    }
+  } else {
+    forget_factor_ += (base_forget_factor_ - forget_factor_ + 3) >> 2;
+  }
 }
 
 int Histogram::Quantile(int probability) {
@@ -112,6 +138,7 @@
     bucket = temp_prob << 16;
   }
   forget_factor_ = 0;  // Adapt the histogram faster for the first few packets.
+  add_count_ = 0;
 }
 
 int Histogram::NumBuckets() const {
diff --git a/modules/audio_coding/neteq/histogram.h b/modules/audio_coding/neteq/histogram.h
index fc8f612..7eb90d9 100644
--- a/modules/audio_coding/neteq/histogram.h
+++ b/modules/audio_coding/neteq/histogram.h
@@ -15,12 +15,16 @@
 
 #include <vector>
 
+#include "absl/types/optional.h"
+
 namespace webrtc {
 
 class Histogram {
  public:
   // Creates histogram with capacity |num_buckets| and |forget_factor| in Q15.
-  Histogram(size_t num_buckets, int forget_factor);
+  Histogram(size_t num_buckets,
+            int forget_factor,
+            absl::optional<double> start_forget_weight = absl::nullopt);
 
   virtual ~Histogram();
 
@@ -43,17 +47,24 @@
   // Returns the probability for each bucket in Q30.
   std::vector<int> buckets() const { return buckets_; }
 
-  int forget_factor() const { return base_forget_factor_; }
-
   // Made public for testing.
   static std::vector<int> ScaleBuckets(const std::vector<int>& buckets,
                                        int old_bucket_width,
                                        int new_bucket_width);
 
+  // Accessors only intended for testing purposes.
+  int base_forget_factor_for_testing() const { return base_forget_factor_; }
+  int forget_factor_for_testing() const { return forget_factor_; }
+  absl::optional<double> start_forget_weight_for_testing() const {
+    return start_forget_weight_;
+  }
+
  private:
   std::vector<int> buckets_;
   int forget_factor_;  // Q15
   const int base_forget_factor_;
+  int add_count_;
+  const absl::optional<double> start_forget_weight_;
 };
 
 }  // namespace webrtc
diff --git a/modules/audio_coding/neteq/histogram_unittest.cc b/modules/audio_coding/neteq/histogram_unittest.cc
index 7a887c8..6255a0c 100644
--- a/modules/audio_coding/neteq/histogram_unittest.cc
+++ b/modules/audio_coding/neteq/histogram_unittest.cc
@@ -168,4 +168,15 @@
   EXPECT_EQ(scaled_buckets, expected_result);
 }
 
+TEST(HistogramTest, ReachSteadyStateForgetFactor) {
+  static constexpr int kSteadyStateForgetFactor = (1 << 15) * 0.9993;
+  Histogram histogram(100, kSteadyStateForgetFactor, 1.0);
+  histogram.Reset();
+  int n = (1 << 15) / ((1 << 15) - kSteadyStateForgetFactor);
+  for (int i = 0; i < n; ++i) {
+    histogram.Add(0);
+  }
+  EXPECT_EQ(histogram.forget_factor_for_testing(), kSteadyStateForgetFactor);
+}
+
 }  // namespace webrtc