Added a bitexactness test for the level estimator in the audio processing module

webrtc/modules/audio_processing/level_estimator_bitexactness_unittest.cc

Index: webrtc/modules/audio_processing/level_estimator_bitexactness_unittest.cc
diff --git a/webrtc/modules/audio_processing/level_estimator_bitexactness_unittest.cc b/webrtc/modules/audio_processing/level_estimator_bitexactness_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d833d374c394231263f094374ff1fbdd76c2cf86
--- /dev/null
+++ b/webrtc/modules/audio_processing/level_estimator_bitexactness_unittest.cc
@@ -0,0 +1,203 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.

[hlundin-webrtc, 2016/03/16 12:57:05]

2016

[peah-webrtc, 2016/03/17 14:18:06]

Done.

+ *
+ *  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 <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/random.h"
+#include "webrtc/modules/audio_processing/audio_buffer.h"
+#include "webrtc/modules/audio_processing/level_estimator_impl.h"
+#include "webrtc/modules/audio_processing/test/audio_buffer_tools.h"
+#include "webrtc/modules/audio_processing/test/bitexactness_tools.h"
+
+namespace webrtc {
+namespace {
+
+enum TestSignalLevels { kLow, kMedium, kHigh };
+
+// Process one frame of data and produce the output.
+void ProcessOneFrame(int sample_rate_hz,
+                     AudioBuffer* audio_buffer,
+                     LevelEstimatorImpl* level_estimator,
+                     int* rms) {
+  if (sample_rate_hz > AudioProcessing::kSampleRate16kHz) {

[hlundin-webrtc, 2016/03/16 12:57:05]

What is the purpose of splitting and merging bands without anything in between?
I'm sure these is some purpose, but please document it.

[peah-webrtc, 2016/03/17 14:18:06]

None, removed that code.
Done.

+    audio_buffer->SplitIntoFrequencyBands();
+  }
+
+  if (sample_rate_hz > AudioProcessing::kSampleRate16kHz) {
+    audio_buffer->MergeFrequencyBands();
+  }
+  level_estimator->ProcessStream(audio_buffer);
+  *rms = level_estimator->RMS();
+}
+
+// Forms a predefined random test vector.
+void ConstructTestVector(int samples_per_channel,

[hlundin-webrtc, 2016/03/16 12:57:05]

This seems very similar to the function in the previous CL. Can you consolidate
them? If not, please, consider my comments in that CL and apply them here too.

[peah-webrtc, 2016/03/17 14:18:06]

Done.

+                         int num_channels,
+                         int frame_counter,
+                         Random* rand_gen,
+                         TestSignalLevels signal_level,
+                         std::vector<float>* testvector) {
+  testvector->resize(samples_per_channel * num_channels);
+
+  float signal_gain = 0.0f;
+  switch (signal_level) {
+    case TestSignalLevels::kLow:
+      signal_gain = 0.1f;
+      break;
+    case TestSignalLevels::kMedium:
+      signal_gain = 0.5f;
+      break;
+    case TestSignalLevels::kHigh:
+      signal_gain = 1.0f;
+      break;
+    default:
+      RTC_DCHECK(false);
+  }
+
+  bool low_level = ((frame_counter / 10) > 5);
+  float scale = (low_level ? 0.01f : 1.0f);
+  for (auto& v : *testvector) {
+    v = signal_gain * scale * (2.0f * rand_gen->Rand<float>() - 1.0f);
+  }
+}
+
+void SetupComponent(LevelEstimatorImpl* level_estimator) {
+  level_estimator->Initialize();
+  level_estimator->Enable(true);
+}
+
+// Processes a specified amount of frames, verifies the results and reports
+// any errors.
+void RunBitexactnessTest(int sample_rate_hz,

[minyue-webrtc, 2016/03/16 09:55:01]

Is |rms_reference| derivable from |signal_level|, or a predefined std::map?

[peah-webrtc, 2016/03/17 14:18:06]

No, signal_level was just a scaling of the signal to try to test the
level-dependency of the level estimator. I removed that though since it mainly
complicates the test.

Done.

+                         int num_channels,
+                         int num_frames_to_process,
+                         TestSignalLevels signal_level,
+                         int rms_reference) {
+  Random rand_gen(42);
+  int samples_per_channel = 80 * sample_rate_hz / 8000;
+  const StreamConfig stream_config(sample_rate_hz, num_channels, false);
+  AudioBuffer audio_buffer(
+      stream_config.num_frames(), stream_config.num_channels(),
+      stream_config.num_frames(), stream_config.num_channels(),
+      stream_config.num_frames());
+
+  rtc::CriticalSection crit;
+  LevelEstimatorImpl level_estimator(&crit);
+  SetupComponent(&level_estimator);
+
+  int rms = 0;
+  std::vector<float> frame_input;
+  for (int frame_no = 0; frame_no < num_frames_to_process; ++frame_no) {
+    ConstructTestVector(samples_per_channel, num_channels, frame_no, &rand_gen,
+                        signal_level, &frame_input);
+
+    test::CopyVectorToAudioBuffer(stream_config, frame_input, &audio_buffer);
+
+    ProcessOneFrame(sample_rate_hz, &audio_buffer, &level_estimator, &rms);
+  }
+
+  // Compare the output to the reference.
+  EXPECT_PRED_FORMAT2(test::AssertIntegersNotEqual, rms, rms_reference);

[hlundin-webrtc, 2016/03/16 12:57:05]

EXPECT_NEAR

[peah-webrtc, 2016/03/17 14:18:06]

Changed to EXPECT_EQ instead.
Done.

+}
+
+}  // namespace
+
+TEST(LevelEstimatorBitExactnessTest, Mono8kHzLow) {
+  const int kRmsReference = 65;

[hlundin-webrtc, 2016/03/16 12:57:05]

You are using three different values for kRmsReference. Add them as distinct
constants in the unnamed namespace, (kLowRmsReference, ...), and don't define
them in each TEST.

[peah-webrtc, 2016/03/17 14:18:06]

I'm not too happy about that. It may be that they will differ for the different
tests. I'd rather have them gathered inside the actual test. I have rewrite it a
bit now though. Please let me know what you think!

[hlundin-webrtc, 2016/03/17 15:20:57]

Fair enough, now that you have fewer test cases.

[peah-webrtc, 2016/03/20 15:40:55]

Acknowledged.

+
+  RunBitexactnessTest(8000, 1, 200, TestSignalLevels::kLow, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono16kHzLow) {
+  const int kRmsReference = 65;
+
+  RunBitexactnessTest(16000, 1, 200, TestSignalLevels::kLow, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono32kHzLow) {
+  const int kRmsReference = 65;
+
+  RunBitexactnessTest(32000, 1, 200, TestSignalLevels::kLow, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono48kHzLow) {
+  const int kRmsReference = 65;
+
+  RunBitexactnessTest(48000, 1, 200, TestSignalLevels::kLow, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Stereo16kHzLow) {
+  const int kRmsReference = 65;
+
+  RunBitexactnessTest(16000, 2, 200, TestSignalLevels::kLow, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono8kHzMedium) {
+  const int kRmsReference = 51;
+
+  RunBitexactnessTest(8000, 1, 200, TestSignalLevels::kMedium, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono16kHzMedium) {
+  const int kRmsReference = 51;
+
+  RunBitexactnessTest(16000, 1, 200, TestSignalLevels::kMedium, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono32kHzMedium) {
+  const int kRmsReference = 51;
+
+  RunBitexactnessTest(32000, 1, 200, TestSignalLevels::kMedium, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono48kHzMedium) {
+  const int kRmsReference = 51;
+
+  RunBitexactnessTest(48000, 1, 200, TestSignalLevels::kMedium, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Stereo16kHzMedium) {
+  const int kRmsReference = 51;
+
+  RunBitexactnessTest(16000, 2, 200, TestSignalLevels::kMedium, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono8kHzHigh) {
+  const int kRmsReference = 45;
+
+  RunBitexactnessTest(8000, 1, 200, TestSignalLevels::kHigh, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono16kHzHigh) {
+  const int kRmsReference = 45;
+
+  RunBitexactnessTest(16000, 1, 200, TestSignalLevels::kHigh, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono32kHzHigh) {
+  const int kRmsReference = 45;
+
+  RunBitexactnessTest(32000, 1, 200, TestSignalLevels::kHigh, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Mono48kHzHigh) {
+  const int kRmsReference = 45;
+
+  RunBitexactnessTest(48000, 1, 200, TestSignalLevels::kHigh, kRmsReference);
+}
+
+TEST(LevelEstimatorBitExactnessTest, Stereo16kHzHigh) {
+  const int kRmsReference = 45;
+
+  RunBitexactnessTest(16000, 2, 200, TestSignalLevels::kHigh, kRmsReference);
+}
+
+}  // namespace webrtc