Send data from mixer to APM limiter more often.

webrtc/modules/audio_mixer/frame_combiner_unittest.cc

 /*
  *  Copyright (c) 2017 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 "webrtc/modules/audio_mixer/frame_combiner.h"
 
 #include <numeric>
 #include <sstream>
 #include <string>
 
+#include "webrtc/audio/utility/audio_frame_operations.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/modules/audio_mixer/gain_change_calculator.h"
+#include "webrtc/modules/audio_mixer/sine_wave_generator.h"
 #include "webrtc/test/gtest.h"
 
 namespace webrtc {
 
 namespace {
 std::string ProduceDebugText(int sample_rate_hz,
                              int number_of_channels,
                              int number_of_sources) {
   std::ostringstream ss;
-  ss << "Sample rate: " << sample_rate_hz << " ";
-  ss << "Number of channels: " << number_of_channels << " ";
-  ss << "Number of sources: " << number_of_sources;
+  ss << "Sample rate: " << sample_rate_hz << " ,";
+  ss << "number of channels: " << number_of_channels << " ,";
+  ss << "number of sources: " << number_of_sources;
   return ss.str();
 }
 
+std::string ProduceDebugText(int sample_rate_hz,
+                             int number_of_channels,
+                             int number_of_sources,
+                             bool limiter_active,
+                             float wave_frequency) {
+  std::ostringstream ss;
+  ss << "Sample rate: " << sample_rate_hz << " ,";
+  ss << "number of channels: " << number_of_channels << " ,";
+  ss << "number of sources: " << number_of_sources << " ,";
+  ss << "limiter active: " << (limiter_active ? "true" : "false") << " ,";
+  ss << "wave frequency: " << wave_frequency << " ,";
+  return ss.str();
+}
+
 AudioFrame frame1;
 AudioFrame frame2;
 AudioFrame audio_frame_for_mixing;
 
 void SetUpFrames(int sample_rate_hz, int number_of_channels) {
   for (auto* frame : {&frame1, &frame2}) {
     frame->UpdateFrame(-1, 0, nullptr,
                        rtc::CheckedDivExact(sample_rate_hz, 100),
                        sample_rate_hz, AudioFrame::kNormalSpeech,
                        AudioFrame::kVadActive, number_of_channels);
   }
 }
 }  // namespace
 
 TEST(FrameCombiner, BasicApiCallsLimiter) {
   FrameCombiner combiner(true);
   for (const int rate : {8000, 16000, 32000, 48000}) {
     for (const int number_of_channels : {1, 2}) {
       const std::vector<AudioFrame*> all_frames = {&frame1, &frame2};
       SetUpFrames(rate, number_of_channels);
 
       for (const int number_of_frames : {0, 1, 2}) {
         SCOPED_TRACE(
             ProduceDebugText(rate, number_of_channels, number_of_frames));
         const std::vector<AudioFrame*> frames_to_combine(
             all_frames.begin(), all_frames.begin() + number_of_frames);
         combiner.Combine(frames_to_combine, number_of_channels, rate,
-                         &audio_frame_for_mixing);
+                         frames_to_combine.size(), &audio_frame_for_mixing);
       }
     }
   }
 }
 
 // No APM limiter means no AudioProcessing::NativeRate restriction
 // on rate. The rate has to be divisible by 100 since we use
 // 10 ms frames, though.
 TEST(FrameCombiner, BasicApiCallsNoLimiter) {
   FrameCombiner combiner(false);
   for (const int rate : {8000, 10000, 11000, 32000, 44100}) {
     for (const int number_of_channels : {1, 2}) {
       const std::vector<AudioFrame*> all_frames = {&frame1, &frame2};
       SetUpFrames(rate, number_of_channels);
 
       for (const int number_of_frames : {0, 1, 2}) {
         SCOPED_TRACE(
             ProduceDebugText(rate, number_of_channels, number_of_frames));
         const std::vector<AudioFrame*> frames_to_combine(
             all_frames.begin(), all_frames.begin() + number_of_frames);
         combiner.Combine(frames_to_combine, number_of_channels, rate,
-                         &audio_frame_for_mixing);
+                         frames_to_combine.size(), &audio_frame_for_mixing);
       }
     }
   }
 }
 
 TEST(FrameCombiner, CombiningZeroFramesShouldProduceSilence) {
   FrameCombiner combiner(false);
   for (const int rate : {8000, 10000, 11000, 32000, 44100}) {
     for (const int number_of_channels : {1, 2}) {
       SCOPED_TRACE(ProduceDebugText(rate, number_of_channels, 0));
 
       const std::vector<AudioFrame*> frames_to_combine;
       combiner.Combine(frames_to_combine, number_of_channels, rate,
-                       &audio_frame_for_mixing);
+                       frames_to_combine.size(), &audio_frame_for_mixing);
 
       const std::vector<int16_t> mixed_data(
           audio_frame_for_mixing.data_,
           audio_frame_for_mixing.data_ + number_of_channels * rate / 100);
 
       const std::vector<int16_t> expected(number_of_channels * rate / 100, 0);
       EXPECT_EQ(mixed_data, expected);
     }
   }
 }
 
 TEST(FrameCombiner, CombiningOneFrameShouldNotChangeFrame) {
   FrameCombiner combiner(false);
   for (const int rate : {8000, 10000, 11000, 32000, 44100}) {
     for (const int number_of_channels : {1, 2}) {
       SCOPED_TRACE(ProduceDebugText(rate, number_of_channels, 1));
 
       SetUpFrames(rate, number_of_channels);
       std::iota(frame1.data_, frame1.data_ + number_of_channels * rate / 100,
                 0);
       const std::vector<AudioFrame*> frames_to_combine = {&frame1};
       combiner.Combine(frames_to_combine, number_of_channels, rate,
-                       &audio_frame_for_mixing);
+                       frames_to_combine.size(), &audio_frame_for_mixing);
 
       const std::vector<int16_t> mixed_data(
           audio_frame_for_mixing.data_,
           audio_frame_for_mixing.data_ + number_of_channels * rate / 100);
 
       std::vector<int16_t> expected(number_of_channels * rate / 100);
       std::iota(expected.begin(), expected.end(), 0);
       EXPECT_EQ(mixed_data, expected);
     }
   }
 }
 
+// Send a sine wave through the FrameCombiner, and check that the
+// difference between input and output varies smoothly. This is to
+// catch issues like chromium:695993.
+TEST(FrameCombiner, GainCurveIsSmoothForAlternatingNumberOfStreams) {
+  // Test doesn't work with rates requiring a band split, because it
+  // introduces a small delay measured in single samples, and this
+  // test cannot handle it.
+  //
+  // TODO(aleloi): Add more rates when APM limiter doesn't use band
+  // split.
+  for (const bool use_limiter : {true, false}) {
+    for (const int rate : {8000, 16000}) {
+      constexpr int number_of_channels = 2;
+      for (const float wave_frequency : {50, 400, 3200}) {
+        SCOPED_TRACE(ProduceDebugText(rate, number_of_channels, 1, use_limiter,
+                                      wave_frequency));
+
+        FrameCombiner combiner(use_limiter);
+
+        constexpr int16_t wave_amplitude = 30000;
+        SineWaveGenerator wave_generator(wave_frequency, wave_amplitude);
+
+        GainChangeCalculator change_calculator;
+        float cumulative_change = 0.f;
+
+        constexpr size_t iterations = 100;
+
+        for (size_t i = 0; i < iterations; ++i) {
+          SetUpFrames(rate, number_of_channels);
+          wave_generator.GenerateNextFrame(&frame1);
+          AudioFrameOperations::Mute(&frame2);
+
+          std::vector<AudioFrame*> frames_to_combine = {&frame1};
+          if (i % 2 == 0) {
+            frames_to_combine.push_back(&frame2);
+          }
+          const size_t number_of_samples =
+              frame1.samples_per_channel_ * number_of_channels;
+
+          // Ensures limiter is on if 'use_limiter'.
+          constexpr size_t number_of_streams = 2;
+          combiner.Combine(frames_to_combine, number_of_channels, rate,
+                           number_of_streams, &audio_frame_for_mixing);
+          cumulative_change += change_calculator.CalculateGainChange(
+              rtc::ArrayView<const int16_t>(frame1.data_, number_of_samples),
+              rtc::ArrayView<const int16_t>(audio_frame_for_mixing.data_,
+                                            number_of_samples));
+        }
+        RTC_DCHECK_LT(cumulative_change, 10);
+      }
+    }
+  }
+}
 }  // namespace webrtc