Adding WebRTC Auto Gain Control Test (linux)

chrome/browser/media/webrtc_browsertest_audio.cc

+// Copyright 2014 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 "webrtc_browsertest_audio.h"
+
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "media/audio/audio_power_monitor.h"
+#include "media/audio/sounds/wav_audio_handler.h"
+#include "media/base/audio_bus.h"
+
+namespace {
+// Opens |wav_filename|, reads it and loads it as a wav file. This function will
+// bluntly trigger CHECKs if we can't read the file or if it's malformed. The
+// caller takes ownership of the returned data. The size of the data is stored
+// in |read_length|.
+scoped_ptr<uint8[]> ReadWavFile(const base::FilePath& wav_filename,
+                                size_t* file_length) {
+  base::File wav_file(
+      wav_filename, base::File::FLAG_OPEN | base::File::FLAG_READ);
+  if (!wav_file.IsValid()) {
+    CHECK(false) << "Failed to read " << wav_filename.value();
+    return nullptr;
+  }
+
+  size_t wav_file_length = wav_file.GetLength();
+
+  uint8* wav_file_data = new uint8[wav_file_length];
+  size_t read_bytes = wav_file.Read(0, reinterpret_cast<char*>(wav_file_data),
+                                    wav_file_length);
+  if (read_bytes != wav_file_length) {
+    CHECK(false) << "Failed to read all bytes of " << wav_filename.value();
+    return nullptr;
+  }
+  *file_length = wav_file_length;
+  return scoped_ptr<uint8[]>(wav_file_data);
+}
+
+scoped_ptr<media::WavAudioHandler> CreateWavAudioHandler(
+    const base::FilePath& wav_filename, const uint8* wav_file_data,
+    size_t wav_file_length) {
+  base::StringPiece wav_data(reinterpret_cast<const char*>(wav_file_data),
+                             wav_file_length);
+  scoped_ptr<media::WavAudioHandler> wav_audio_handler(
+      new media::WavAudioHandler(wav_data));
+
+  return wav_audio_handler.Pass();
+}
+
+}  // namespace
+
+namespace test {
+
+enum { kPowerMeasurementTimeConstantMillis = 10 };
+
+std::vector<float> ComputeAudioEnergyForWavFile(
+    const base::FilePath& wav_filename) {
+  // Read the file, and put its data in a scoped_ptr so it gets deleted later.
+  size_t file_length = 0;
+  scoped_ptr<uint8[]> wav_file_data = ReadWavFile(wav_filename, &file_length);
+  scoped_ptr<media::WavAudioHandler> wav_audio_handler = CreateWavAudioHandler(
+      wav_filename, wav_file_data.get(), file_length);
+
+  // Set up the bus to read 10 ms at a time.

[bjornv, 2014/12/18 11:30:27]

Could we set up the bus to read the entire segment, or controlled by an input
parameter?

+  int num_frames_in_10_ms =
+      10 * wav_audio_handler->params().sample_rate() / 1000;
+  media::AudioParameters bus_params = media::AudioParameters(
+      wav_audio_handler->params().format(),
+      wav_audio_handler->params().channel_layout(),
+      wav_audio_handler->params().sample_rate(),
+      wav_audio_handler->params().bits_per_sample(),
+      num_frames_in_10_ms);
+
+  scoped_ptr<media::AudioBus> audio_bus =
+      media::AudioBus::Create(bus_params);
+  media::AudioPowerMonitor power_monitor(
+      wav_audio_handler->params().sample_rate(),
+      base::TimeDelta::FromMilliseconds(kPowerMeasurementTimeConstantMillis));
+
+  int read_pos = 0;
+  std::vector<float> results;
+
+  while (!wav_audio_handler->AtEnd(read_pos)) {
+    size_t bytes_written;
+    wav_audio_handler->CopyTo(audio_bus.get(), read_pos, &bytes_written);
+    power_monitor.Scan(*audio_bus, audio_bus->frames());
+    results.push_back(power_monitor.ReadCurrentPowerAndClip().first);
+    read_pos += bytes_written;
+  }
+
+  return results;
+}
+
+}  // namespace test