Injectable output rate calculater for AudioMixer.

webrtc/modules/audio_mixer/audio_mixer_impl_unittest.cc

 /*
  *  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 <string.h>
 
 #include <limits>
 #include <memory>
 #include <utility>
 
 #include "webrtc/api/audio/audio_mixer.h"
 #include "webrtc/base/bind.h"
 #include "webrtc/base/thread.h"
 #include "webrtc/modules/audio_mixer/audio_mixer_impl.h"
+#include "webrtc/modules/audio_mixer/default_output_rate_calculator.h"
 #include "webrtc/test/gmock.h"
 
 using testing::_;
 using testing::Exactly;
 using testing::Invoke;
 using testing::Return;
 
 namespace webrtc {
 
 namespace {
@@ skipping 47 matching lines @@
     audio_frame->CopyFrom(fake_frame_);
     audio_frame->sample_rate_hz_ = sample_rate_hz;
     audio_frame->samples_per_channel_ = sample_rate_hz / 100;
     return fake_info();
   }
 
   AudioFrame fake_frame_;
   AudioFrameInfo fake_audio_frame_info_;
 };
 
+class CustomRateCalculator : public OutputRateCalculator {
+ public:
+  explicit CustomRateCalculator(int rate) : rate_(rate) {}
+  int CalculateOutputRate(const std::vector<int>& preferred_rates) {
+    return rate_;
+  }
+
+ private:
+  const int rate_;
+};
+
 // Creates participants from |frames| and |frame_info| and adds them
 // to the mixer. Compares mixed status with |expected_status|
 void MixAndCompare(
     const std::vector<AudioFrame>& frames,
     const std::vector<AudioMixer::Source::AudioFrameInfo>& frame_info,
     const std::vector<bool>& expected_status) {
   int num_audio_sources = frames.size();
   RTC_DCHECK(frames.size() == frame_info.size());
   RTC_DCHECK(frame_info.size() == expected_status.size());
 
@@ skipping 336 matching lines @@
   std::vector<AudioMixer::Source::AudioFrameInfo> frame_info(
       kAudioSources, AudioMixer::Source::AudioFrameInfo::kNormal);
   frame_info[0] = AudioMixer::Source::AudioFrameInfo::kMuted;
   std::fill(frames[0].data_, frames[0].data_ + kDefaultSampleRateHz / 100,
             std::numeric_limits<int16_t>::max());
   std::vector<bool> expected_status(kAudioSources, true);
   expected_status[0] = false;
 
   MixAndCompare(frames, frame_info, expected_status);
 }
+
+TEST(AudioMixer, MixingRateShouldBeDecidedByRateCalculator) {
+  constexpr int kOutputRate = 22000;
+  const auto mixer = AudioMixerImpl::CreateWithOutputRateCalculator(
+      std::unique_ptr<OutputRateCalculator>(
+          new CustomRateCalculator(kOutputRate)));
+  MockMixerAudioSource audio_source;
+  mixer->AddSource(&audio_source);
+  ResetFrame(audio_source.fake_frame());
+
+  EXPECT_CALL(audio_source, GetAudioFrameWithInfo(kOutputRate, _))
+      .Times(Exactly(1));
+
+  mixer->Mix(1, &frame_for_mixing);
+}
+
+TEST(AudioMixer, ZeroSourceRateShouldBeDecidedByRateCalculator) {
+  constexpr int kOutputRate = 8000;
+  const auto mixer = AudioMixerImpl::CreateWithOutputRateCalculator(
+      std::unique_ptr<OutputRateCalculator>(
+          new CustomRateCalculator(kOutputRate)));
+
+  mixer->Mix(1, &frame_for_mixing);
+
+  EXPECT_EQ(kOutputRate, frame_for_mixing.sample_rate_hz_);
+}
 }  // namespace webrtc