Send data from mixer to APM limiter more often.

webrtc/modules/audio_mixer/frame_combiner_test_tools.h

+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_MIXER_FRAME_COMBINER_TEST_TOOLS_H_
+#define WEBRTC_MODULES_AUDIO_MIXER_FRAME_COMBINER_TEST_TOOLS_H_
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/include/module_common_types.h"
+
+namespace webrtc {
+
+class SineWaveGenerator {

[ivoc, 2017/03/28 16:11:06]

Please move to sine_wave_generator.{cc,h}

[aleloi, 2017/03/28 17:10:13]

Done.

+ public:
+  SineWaveGenerator(float wave_frequency_hz, int16_t amplitude)
+      : wave_frequency_hz_(wave_frequency_hz), amplitude_(amplitude) {
+    RTC_DCHECK_GT(wave_frequency_hz, 0);
+  }
+
+  // Produces appropriate output based on frame->num_channels_,
+  // frame->sample_rate_hz_.
+  void GenerateNextFrame(AudioFrame* frame);
+
+ private:
+  float phase_ = 0.f;
+  const float wave_frequency_hz_;
+  const int16_t amplitude_;
+};
+
+class GainChangeCalculator {

[ivoc, 2017/03/28 16:11:06]

And this to gain_change_calculator.{cc,h}

[aleloi, 2017/03/28 17:10:13]

Done.

+ public:
+  // The 'out' signal is assumed to be produced from 'in' by applying
+  // a smoothly varying gain. This method computes variations of the
+  // gain and handles special cases when the samples are small.
+  float CalculateGainChange(rtc::ArrayView<const int16_t> in,
+                            rtc::ArrayView<const int16_t> out);
+
+ private:
+  void CalculateGain(rtc::ArrayView<const int16_t> in,
+                     rtc::ArrayView<const int16_t> out,
+                     rtc::ArrayView<float> gain);
+
+  float CalculateDifferences(rtc::ArrayView<const float> values);
+  float last_value_ = 0.f;
+  float last_reliable_gain_ = 1.0f;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_MIXER_FRAME_COMBINER_TEST_TOOLS_H_