Replace AudioSilenceDetector with an AudioPowerMonitor.

media/audio/audio_power_monitor_unittest.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/audio/audio_power_monitor.h"
+
+#include <cmath>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/message_loop.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/threading/thread.h"
+#include "base/time.h"
+#include "media/base/audio_bus.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::_;
+using ::testing::FloatEq;
+using ::testing::InvokeWithoutArgs;
+using ::testing::TestWithParam;
+using ::testing::Values;
+
+namespace media {
+namespace {
+
+const int kSampleRate = 48000;
+const int kFramesPerBuffer = 128;
+
+class MockObserver {
+ public:
+  MOCK_METHOD1(OnPowerMeasured, void(float));
+};
+
+struct TestScenario {
+  const float* data;
+  int num_channels;
+  int num_frames;
+  float power_in_dbfs;
+
+  TestScenario(const float* d, int c, int f, float p)
+      : data(d), num_channels(c), num_frames(f), power_in_dbfs(p) {}
+};
+
+class AudioPowerMonitorTest : public TestWithParam<TestScenario> {
+ public:
+  AudioPowerMonitorTest()
+      : audio_manager_thread_(new base::Thread("AudioThread")),
+        notification_received_(false, false) {
+    audio_manager_thread_->Start();
+    audio_message_loop_ = audio_manager_thread_->message_loop_proxy();
+  }
+
+  virtual ~AudioPowerMonitorTest() {
+    SyncWithAudioThread();
+  }
+
+  AudioPowerMonitor* power_monitor() const {
+    return power_monitor_.get();
+  }
+
+  void StartPowerMonitor(MockObserver* observer) {
+    audio_message_loop_->PostTask(
+        FROM_HERE,
+        base::Bind(&AudioPowerMonitorTest::StartMonitorOnAudioThread,
+                   base::Unretained(this), observer));
+    SyncWithAudioThread();
+  }
+
+  void StopPowerMonitor() {
+    audio_message_loop_->PostTask(
+        FROM_HERE,
+        base::Bind(&AudioPowerMonitorTest::StopMonitorOnAudioThread,
+                   base::Unretained(this)));
+    SyncWithAudioThread();
+  }
+
+  // Creates an AudioBus, sized and populated with kFramesPerBuffer frames of
+  // data.  The given test |data| is repeated to fill the buffer.
+  scoped_ptr<AudioBus> CreatePopulatedBuffer(
+      const float* data, int num_channels, int num_frames) {
+    scoped_ptr<AudioBus> bus = AudioBus::Create(num_channels, kFramesPerBuffer);

[DaleCurtis, 2013/05/16 18:24:45]

Instead of memcpy, etc, you could just create a wrapped audio bus and
SetChannelData()? You would just need to declare the arrays aligned 16 below.

[miu, 2013/05/16 21:44:11]

This method produces an AudioBus of kFramesPerBuffer in length from the test
data which is num_frames in length.  num_frames is usually only 1-10 samples
(see constants starting on line 183).  Therefore, I need the memcpy() to repeat
the test data to fill the whole buffer.

+    for (int ch = 0; ch < num_channels; ++ch) {
+      for (int frames = 0; frames < kFramesPerBuffer; frames += num_frames) {
+        const int num_to_copy = std::min(num_frames, kFramesPerBuffer - frames);
+        memcpy(bus->channel(ch) + frames, data + num_frames * ch,
+               sizeof(float) * num_to_copy);
+      }
+    }
+    return bus.Pass();
+  }
+
+  scoped_ptr<AudioBus> CreateZeroedBuffer(int num_channels) {
+    scoped_ptr<AudioBus> bus = AudioBus::Create(num_channels, kFramesPerBuffer);
+    bus->Zero();
+    return bus.Pass();
+  }
+
+
+  void SignalNotificationReceived() {
+    notification_received_.Signal();
+  }
+
+  void WaitForNotificationReceived() {
+    notification_received_.Wait();
+  }
+
+  // Post a task on the audio thread and block until it is executed.  This
+  // provides a barrier: All previous tasks pending on the audio thread have
+  // completed before this method returns.
+  void SyncWithAudioThread() {
+    base::WaitableEvent done(false, false);
+    audio_message_loop_->PostTask(
+        FROM_HERE,
+        base::Bind(&base::WaitableEvent::Signal, base::Unretained(&done)));
+    done.Wait();
+  }
+
+ private:
+  void StartMonitorOnAudioThread(MockObserver* observer) {
+    const AudioPowerMonitor::PowerMeasurementCallback callback =
+        base::Bind(&MockObserver::OnPowerMeasured, base::Unretained(observer));
+    power_monitor_.reset(new AudioPowerMonitor(
+        kSampleRate, base::TimeDelta::FromMilliseconds(1),
+        MessageLoop::current(), callback));
+  }
+
+  void StopMonitorOnAudioThread() {
+    power_monitor_.reset();
+  }
+
+  scoped_ptr<base::Thread> audio_manager_thread_;
+  scoped_refptr<base::MessageLoopProxy> audio_message_loop_;
+
+  base::WaitableEvent notification_received_;
+
+  scoped_ptr<AudioPowerMonitor> power_monitor_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioPowerMonitorTest);
+};
+
+TEST_P(AudioPowerMonitorTest, MeasuresPowerOfSignal) {
+  const TestScenario& scenario = GetParam();
+
+  MockObserver observer;
+  StartPowerMonitor(&observer);
+
+  // Send silence and expect a callback with a "zero power" result.
+  EXPECT_CALL(observer,
+              OnPowerMeasured(FloatEq(AudioPowerMonitor::kZeroPowerDBFS)))
+      .WillOnce(InvokeWithoutArgs(
+          this, &AudioPowerMonitorTest::SignalNotificationReceived))
+      .RetiresOnSaturation();
+  scoped_ptr<AudioBus> bus = CreateZeroedBuffer(scenario.num_channels);
+  power_monitor()->Scan(bus.get(), bus->frames());
+  WaitForNotificationReceived();
+
+  // Send audio signal data to the power monitor and expect a callback with the
+  // correct result.
+  EXPECT_CALL(observer, OnPowerMeasured(FloatEq(scenario.power_in_dbfs)))
+      .WillOnce(InvokeWithoutArgs(
+          this, &AudioPowerMonitorTest::SignalNotificationReceived))
+      .RetiresOnSaturation();
+  bus = CreatePopulatedBuffer(
+      scenario.data, scenario.num_channels, scenario.num_frames);
+  power_monitor()->Scan(bus.get(), bus->frames());
+  WaitForNotificationReceived();
+
+  // Send silence again and expect a callback with a "zero power" result again.
+  EXPECT_CALL(observer,
+              OnPowerMeasured(FloatEq(AudioPowerMonitor::kZeroPowerDBFS)))
+      .WillOnce(InvokeWithoutArgs(
+          this, &AudioPowerMonitorTest::SignalNotificationReceived))
+      .RetiresOnSaturation();
+  bus = CreateZeroedBuffer(scenario.num_channels);
+  power_monitor()->Scan(bus.get(), bus->frames());
+  WaitForNotificationReceived();
+
+  StopPowerMonitor();
+}
+
+const float kMonoSilence[] = {
+  0.0f
+};
+
+const float kMonoMaxAmplitude[] = {
+  1.0f
+};
+
+const float kMonoMaxAmplitude2[] = {
+  -1.0f, 1.0f,
+};
+
+const float kMonoHalfMaxAmplitude[] = {
+  0.5f, -0.5f, 0.5f, -0.5f
+};
+
+const float kStereoSilence[] = {
+  // left channel
+  0.0f,
+  // right channel
+  0.0f
+};
+
+const float kStereoMaxAmplitude[] = {
+  // left channel
+  1.0f, -1.0f,
+  // right channel
+  -1.0f, 1.0f
+};
+
+const float kRightChannelMaxAmplitude[] = {
+  // left channel
+  0.0f, 0.0f, 0.0f, 0.0f,
+  // right channel
+  -1.0f, 1.0f, -1.0f, 1.0f
+};
+
+const float kLeftChannelHalfMaxAmplitude[] = {
+  // left channel
+  0.5f, -0.5f, 0.5f, -0.5f,
+  // right channel
+  0.0f, 0.0f, 0.0f, 0.0f,
+};
+
+const float kStereoMixed[] = {
+  // left channel
+  0.5f, -0.5f, 0.5f, -0.5f,
+  // right channel
+  -1.0f, 1.0f, -1.0f, 1.0f
+};
+
+const float kStereoMixed2[] = {
+  // left channel
+  1.0f, -1.0f, 0.5f, -0.5f, 0.25f, -0.25f, 0.125f, -0.125f,
+  // right channel
+  0.125f, -0.125f, 0.25f, -0.25f, 0.5f, -0.5f, 1.0f, -1.0f
+};
+

[DaleCurtis, 2013/05/16 18:24:45]

A test case with values outside of [-1, 1] would be good.

[miu, 2013/05/16 21:44:11]

Done.  And also added ones containing infinity and NaN.

+INSTANTIATE_TEST_CASE_P(
+    Scenarios, AudioPowerMonitorTest,
+    Values(
+        TestScenario(kMonoSilence, 1, 1,
+                     AudioPowerMonitor::kZeroPowerDBFS),
+        TestScenario(kMonoMaxAmplitude, 1, 1,
+                     AudioPowerMonitor::kMaxPowerDBFS),
+        TestScenario(kMonoMaxAmplitude2, 1, 2,
+                     AudioPowerMonitor::kMaxPowerDBFS),
+        TestScenario(kMonoHalfMaxAmplitude, 1, 4,
+                     -6.0206f),
+        TestScenario(kStereoSilence, 2, 1,
+                     AudioPowerMonitor::kZeroPowerDBFS),
+        TestScenario(kStereoMaxAmplitude, 2, 2,
+                     AudioPowerMonitor::kMaxPowerDBFS),
+        TestScenario(kRightChannelMaxAmplitude, 2, 4,
+                     -3.0103f),
+        TestScenario(kLeftChannelHalfMaxAmplitude, 2, 4,
+                     -9.0309f),
+        TestScenario(kStereoMixed, 2, 4,
+                     -2.0412f),
+        TestScenario(kStereoMixed2, 2, 8,
+                     -4.78821f)));
+
+}  // namespace

[DaleCurtis, 2013/05/16 18:24:45]

This is a bit weird?  For media/ we generally leave everything in the media
namespace and static const values.

[miu, 2013/05/16 21:44:11]

Yes and no.  I actually came up against the following problem when working on
media unit tests in the past: Two different unit test modules declared a class
called MockAudioOutputStream with different implementations.  The linker for
media_unittests picked one of them to use for both tests and then, as expected,
one of the test suites crashed at run-time.

The solution is that test code should be declared in an anonymous namespace as a
precaution.  Though, to match with media coding style, I've put back all the
constants to static and only use the anonymous namespace around the helper class
definitions.

+}  // namespace media