Move MovingAverage to rtc_base/numerics and update it.

This utility class is needed in rtcp_rtp. Instead of reimplementing it
again, the existing class is moved to rtc_base, cleaned from unused
features and extended as required for the new usage.

Bug: webrtc:9914
Change-Id: I3b0d83d08d8fa5e1384b4721a93c6a90781948fd
Reviewed-on: https://webrtc-review.googlesource.com/c/109081
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25498}

modules/video_coding/BUILD.gn

@@ -240,8 +240,6 @@ rtc_source_set("video_coding_utility") {
     "utility/framerate_controller.h",
     "utility/ivf_file_writer.cc",
     "utility/ivf_file_writer.h",
-    "utility/moving_average.cc",
-    "utility/moving_average.h",
     "utility/quality_scaler.cc",
     "utility/quality_scaler.h",
     "utility/simulcast_rate_allocator.cc",
@@ -858,7 +856,6 @@ if (rtc_include_tests) {
       "utility/frame_dropper_unittest.cc",
       "utility/framerate_controller_unittest.cc",
       "utility/ivf_file_writer_unittest.cc",
-      "utility/moving_average_unittest.cc",
       "utility/quality_scaler_unittest.cc",
       "utility/simulcast_rate_allocator_unittest.cc",
       "video_codec_initializer_unittest.cc",

modules/video_coding/utility/moving_average.cc

@@ -1,47 +0,0 @@
-/*
- *  Copyright (c) 2016 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 "modules/video_coding/utility/moving_average.h"
-
-#include <algorithm>
-
-namespace webrtc {
-
-MovingAverage::MovingAverage(size_t s) : sum_history_(s + 1, 0) {}
-MovingAverage::~MovingAverage() = default;
-
-void MovingAverage::AddSample(int sample) {
-  count_++;
-  sum_ += sample;
-  sum_history_[count_ % sum_history_.size()] = sum_;
-}
-
-absl::optional<int> MovingAverage::GetAverage() const {
-  return GetAverage(size());
-}
-
-absl::optional<int> MovingAverage::GetAverage(size_t num_samples) const {
-  if (num_samples > size() || num_samples == 0)
-    return absl::nullopt;
-  int sum = sum_ - sum_history_[(count_ - num_samples) % sum_history_.size()];
-  return sum / static_cast<int>(num_samples);
-}
-
-void MovingAverage::Reset() {
-  count_ = 0;
-  sum_ = 0;
-  std::fill(sum_history_.begin(), sum_history_.end(), 0);
-}
-
-size_t MovingAverage::size() const {
-  return std::min(count_, sum_history_.size() - 1);
-}
-
-}  // namespace webrtc

modules/video_coding/utility/moving_average.h

@@ -1,36 +0,0 @@
-/*
- *  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.
- */
-
-#ifndef MODULES_VIDEO_CODING_UTILITY_MOVING_AVERAGE_H_
-#define MODULES_VIDEO_CODING_UTILITY_MOVING_AVERAGE_H_
-
-#include <vector>
-
-#include "absl/types/optional.h"
-
-namespace webrtc {
-class MovingAverage {
- public:
-  explicit MovingAverage(size_t s);
-  ~MovingAverage();
-  void AddSample(int sample);
-  absl::optional<int> GetAverage() const;
-  absl::optional<int> GetAverage(size_t num_samples) const;
-  void Reset();
-  size_t size() const;
-
- private:
-  size_t count_ = 0;
-  int sum_ = 0;
-  std::vector<int> sum_history_;
-};
-}  // namespace webrtc
-
-#endif  // MODULES_VIDEO_CODING_UTILITY_MOVING_AVERAGE_H_

modules/video_coding/utility/moving_average_unittest.cc

@@ -1,62 +0,0 @@
-/*
- *  Copyright (c) 2016 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 "modules/video_coding/utility/moving_average.h"
-
-#include "test/gtest.h"
-
-TEST(MovingAverageTest, EmptyAverage) {
-  webrtc::MovingAverage moving_average(1);
-  EXPECT_EQ(0u, moving_average.size());
-  EXPECT_FALSE(moving_average.GetAverage(0));
-}
-
-// Test single value.
-TEST(MovingAverageTest, OneElement) {
-  webrtc::MovingAverage moving_average(1);
-  moving_average.AddSample(3);
-  EXPECT_EQ(1u, moving_average.size());
-  EXPECT_EQ(3, *moving_average.GetAverage());
-  EXPECT_EQ(3, *moving_average.GetAverage(1));
-  EXPECT_FALSE(moving_average.GetAverage(2));
-}
-
-TEST(MovingAverageTest, GetAverage) {
-  webrtc::MovingAverage moving_average(1024);
-  moving_average.AddSample(1);
-  moving_average.AddSample(1);
-  moving_average.AddSample(3);
-  moving_average.AddSample(3);
-  EXPECT_EQ(*moving_average.GetAverage(4), 2);
-  EXPECT_EQ(*moving_average.GetAverage(2), 3);
-  EXPECT_FALSE(moving_average.GetAverage(0));
-}
-
-TEST(MovingAverageTest, Reset) {
-  webrtc::MovingAverage moving_average(5);
-  moving_average.AddSample(1);
-  EXPECT_EQ(1, *moving_average.GetAverage(1));
-  moving_average.Reset();
-  EXPECT_FALSE(moving_average.GetAverage(1));
-  EXPECT_FALSE(moving_average.GetAverage(6));
-}
-
-TEST(MovingAverageTest, ManySamples) {
-  webrtc::MovingAverage moving_average(10);
-  for (int i = 1; i < 11; i++) {
-    moving_average.AddSample(i);
-  }
-  EXPECT_EQ(*moving_average.GetAverage(), 5);
-  moving_average.Reset();
-  for (int i = 1; i < 2001; i++) {
-    moving_average.AddSample(i);
-  }
-  EXPECT_EQ(*moving_average.GetAverage(), 1995);
-}

modules/video_coding/utility/quality_scaler.cc

@@ -173,8 +173,8 @@ void QualityScaler::CheckQp() {
   // If we have not observed at least this many frames we can't make a good
   // scaling decision.
   const size_t frames = config_.use_all_drop_reasons
-                            ? framedrop_percent_all_.size()
-                            : framedrop_percent_media_opt_.size();
+                            ? framedrop_percent_all_.Size()
+                            : framedrop_percent_media_opt_.Size();
   if (frames < kMinFramesNeededToScale) {
     observed_enough_frames_ = false;
     return;
@@ -183,8 +183,9 @@ void QualityScaler::CheckQp() {
 
   // Check if we should scale down due to high frame drop.
   const absl::optional<int> drop_rate =
-      config_.use_all_drop_reasons ? framedrop_percent_all_.GetAverage()
-                                   : framedrop_percent_media_opt_.GetAverage();
+      config_.use_all_drop_reasons
+          ? framedrop_percent_all_.GetAverageRoundedDown()
+          : framedrop_percent_media_opt_.GetAverageRoundedDown();
   if (drop_rate && *drop_rate >= kFramedropPercentThreshold) {
     RTC_LOG(LS_INFO) << "Reporting high QP, framedrop percent " << *drop_rate;
     ReportQpHigh();
@@ -192,11 +193,12 @@ void QualityScaler::CheckQp() {
   }
 
   // Check if we should scale up or down based on QP.
-  const absl::optional<int> avg_qp_high = qp_smoother_high_
-                                              ? qp_smoother_high_->GetAvg()
-                                              : average_qp_.GetAverage();
+  const absl::optional<int> avg_qp_high =
+      qp_smoother_high_ ? qp_smoother_high_->GetAvg()
+                        : average_qp_.GetAverageRoundedDown();
   const absl::optional<int> avg_qp_low =
-      qp_smoother_low_ ? qp_smoother_low_->GetAvg() : average_qp_.GetAverage();
+      qp_smoother_low_ ? qp_smoother_low_->GetAvg()
+                       : average_qp_.GetAverageRoundedDown();
   if (avg_qp_high && avg_qp_low) {
     RTC_LOG(LS_INFO) << "Checking average QP " << *avg_qp_high << " ("
                      << *avg_qp_low << ").";

modules/video_coding/utility/quality_scaler.h

@@ -17,8 +17,8 @@
 #include "absl/types/optional.h"
 #include "api/video_codecs/video_encoder.h"
 #include "common_types.h"  // NOLINT(build/include)
-#include "modules/video_coding/utility/moving_average.h"
 #include "rtc_base/experiments/quality_scaling_experiment.h"
+#include "rtc_base/numerics/moving_average.h"
 #include "rtc_base/sequenced_task_checker.h"
 
 namespace webrtc {
@@ -79,9 +79,10 @@ class QualityScaler {
   const VideoEncoder::QpThresholds thresholds_;
   const int64_t sampling_period_ms_;
   bool fast_rampup_ RTC_GUARDED_BY(&task_checker_);
-  MovingAverage average_qp_ RTC_GUARDED_BY(&task_checker_);
-  MovingAverage framedrop_percent_media_opt_ RTC_GUARDED_BY(&task_checker_);
-  MovingAverage framedrop_percent_all_ RTC_GUARDED_BY(&task_checker_);
+  rtc::MovingAverage average_qp_ RTC_GUARDED_BY(&task_checker_);
+  rtc::MovingAverage framedrop_percent_media_opt_
+      RTC_GUARDED_BY(&task_checker_);
+  rtc::MovingAverage framedrop_percent_all_ RTC_GUARDED_BY(&task_checker_);
 
   // Used by QualityScalingExperiment.
   const bool experiment_enabled_;

rtc_base/BUILD.gn

@@ -68,7 +68,7 @@ rtc_source_set("compile_assert_c") {
 }
 
 # The subset of rtc_base approved for use outside of libjingle.
-# TODO(bugs.webrtc.org/9838): Create small and focues build targets and remove
+# TODO(bugs.webrtc.org/9838): Create small and focused build targets and remove
 # the old concept of rtc_base and rtc_base_approved.
 rtc_source_set("rtc_base_approved") {
   visibility = [ "*" ]
@@ -656,6 +656,8 @@ rtc_static_library("rtc_numerics") {
   sources = [
     "numerics/exp_filter.cc",
     "numerics/exp_filter.h",
+    "numerics/moving_average.cc",
+    "numerics/moving_average.h",
     "numerics/moving_median_filter.h",
     "numerics/percentile_filter.h",
     "numerics/sequence_number_util.h",
@@ -1211,6 +1213,7 @@ if (rtc_include_tests) {
 
     sources = [
       "numerics/exp_filter_unittest.cc",
+      "numerics/moving_average_unittest.cc",
       "numerics/moving_median_filter_unittest.cc",
       "numerics/percentile_filter_unittest.cc",
       "numerics/sequence_number_util_unittest.cc",

rtc_base/numerics/moving_average.cc

@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2018 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 "rtc_base/numerics/moving_average.h"
+
+#include <algorithm>
+
+#include "rtc_base/checks.h"
+
+namespace rtc {
+
+MovingAverage::MovingAverage(size_t window_size) : history_(window_size, 0) {
+  // Limit window size to avoid overflow.
+  RTC_DCHECK_LE(window_size, (int64_t{1} << 32) - 1);
+}
+MovingAverage::~MovingAverage() = default;
+
+void MovingAverage::AddSample(int sample) {
+  count_++;
+  size_t index = count_ % history_.size();
+  if (count_ > history_.size())
+    sum_ -= history_[index];
+  sum_ += sample;
+  history_[index] = sample;
+}
+
+absl::optional<int> MovingAverage::GetAverageRoundedDown() const {
+  if (count_ == 0)
+    return absl::nullopt;
+  return sum_ / Size();
+}
+
+absl::optional<int> MovingAverage::GetAverageRoundedToClosest() const {
+  if (count_ == 0)
+    return absl::nullopt;
+  return (sum_ + Size() / 2) / Size();
+}
+
+absl::optional<double> MovingAverage::GetUnroundedAverage() const {
+  if (count_ == 0)
+    return absl::nullopt;
+  return sum_ / static_cast<double>(Size());
+}
+
+void MovingAverage::Reset() {
+  count_ = 0;
+  sum_ = 0;
+}
+
+size_t MovingAverage::Size() const {
+  return std::min(count_, history_.size());
+}
+}  // namespace rtc

rtc_base/numerics/moving_average.h

@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2018 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.
+ */
+
+#ifndef RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
+#define RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
+
+#include <vector>
+
+#include "absl/types/optional.h"
+
+namespace rtc {
+
+// Calculates average over fixed size window. If there are less than window
+// size elements, calculates average of all inserted so far elements.
+//
+class MovingAverage {
+ public:
+  // Maximum supported window size is 2^32 - 1.
+  explicit MovingAverage(size_t window_size);
+  ~MovingAverage();
+  // MovingAverage is neither copyable nor movable.
+  MovingAverage(const MovingAverage&) = delete;
+  MovingAverage& operator=(const MovingAverage&) = delete;
+
+  // Adds new sample. If the window is full, the oldest element is pushed out.
+  void AddSample(int sample);
+
+  // Returns rounded down average of last |window_size| elements or all
+  // elements if there are not enough of them. Returns nullopt if there were
+  // no elements added.
+  absl::optional<int> GetAverageRoundedDown() const;
+
+  // Same as above but rounded to the closest integer.
+  absl::optional<int> GetAverageRoundedToClosest() const;
+
+  // Returns unrounded average over the window.
+  absl::optional<double> GetUnroundedAverage() const;
+
+  // Resets to the initial state before any elements were added.
+  void Reset();
+
+  // Returns number of elements in the window.
+  size_t Size() const;
+
+ private:
+  // Total number of samples added to the class since last reset.
+  size_t count_ = 0;
+  // Sum of the samples in the moving window.
+  int64_t sum_ = 0;
+  // Circular buffer for all the samples in the moving window.
+  // Size is always |window_size|
+  std::vector<int> history_;
+};
+
+}  // namespace rtc
+#endif  // RTC_BASE_NUMERICS_MOVING_AVERAGE_H_

rtc_base/numerics/moving_average_unittest.cc

@@ -0,0 +1,87 @@
+/*
+ *  Copyright (c) 2018 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 "rtc_base/numerics/moving_average.h"
+
+#include "test/gtest.h"
+
+namespace test {
+
+TEST(MovingAverageTest, EmptyAverage) {
+  rtc::MovingAverage moving_average(1);
+  EXPECT_EQ(0u, moving_average.Size());
+  EXPECT_EQ(absl::nullopt, moving_average.GetAverageRoundedDown());
+}
+
+// Test single value.
+TEST(MovingAverageTest, OneElement) {
+  rtc::MovingAverage moving_average(1);
+  moving_average.AddSample(3);
+  EXPECT_EQ(1u, moving_average.Size());
+  EXPECT_EQ(3, *moving_average.GetAverageRoundedDown());
+}
+
+TEST(MovingAverageTest, GetAverage) {
+  rtc::MovingAverage moving_average(1024);
+  moving_average.AddSample(1);
+  moving_average.AddSample(1);
+  moving_average.AddSample(3);
+  moving_average.AddSample(3);
+  EXPECT_EQ(*moving_average.GetAverageRoundedDown(), 2);
+  EXPECT_EQ(*moving_average.GetAverageRoundedToClosest(), 2);
+}
+
+TEST(MovingAverageTest, GetAverageRoundedDownRounds) {
+  rtc::MovingAverage moving_average(1024);
+  moving_average.AddSample(1);
+  moving_average.AddSample(2);
+  moving_average.AddSample(2);
+  moving_average.AddSample(2);
+  EXPECT_EQ(*moving_average.GetAverageRoundedDown(), 1);
+}
+
+TEST(MovingAverageTest, GetAverageRoundedToClosestRounds) {
+  rtc::MovingAverage moving_average(1024);
+  moving_average.AddSample(1);
+  moving_average.AddSample(2);
+  moving_average.AddSample(2);
+  moving_average.AddSample(2);
+  EXPECT_EQ(*moving_average.GetAverageRoundedToClosest(), 2);
+}
+
+TEST(MovingAverageTest, Reset) {
+  rtc::MovingAverage moving_average(5);
+  moving_average.AddSample(1);
+  EXPECT_EQ(1, *moving_average.GetAverageRoundedDown());
+  EXPECT_EQ(1, *moving_average.GetAverageRoundedToClosest());
+
+  moving_average.Reset();
+
+  EXPECT_FALSE(moving_average.GetAverageRoundedDown());
+  moving_average.AddSample(10);
+  EXPECT_EQ(10, *moving_average.GetAverageRoundedDown());
+  EXPECT_EQ(10, *moving_average.GetAverageRoundedToClosest());
+}
+
+TEST(MovingAverageTest, ManySamples) {
+  rtc::MovingAverage moving_average(10);
+  for (int i = 1; i < 11; i++) {
+    moving_average.AddSample(i);
+  }
+  EXPECT_EQ(*moving_average.GetAverageRoundedDown(), 5);
+  EXPECT_EQ(*moving_average.GetAverageRoundedToClosest(), 6);
+  for (int i = 1; i < 2001; i++) {
+    moving_average.AddSample(i);
+  }
+  EXPECT_EQ(*moving_average.GetAverageRoundedDown(), 1995);
+  EXPECT_EQ(*moving_average.GetAverageRoundedToClosest(), 1996);
+}
+
+}  // namespace test