1 files changed, 235 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/test/conversational_speech/simulator.cc b/third_party/libwebrtc/modules/audio_processing/test/conversational_speech/simulator.cc
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index 0000000000..89bcd48d84
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+++ b/third_party/libwebrtc/modules/audio_processing/test/conversational_speech/simulator.cc
@@ -0,0 +1,235 @@
+/*
+ *  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.
+ */
+
+#include "modules/audio_processing/test/conversational_speech/simulator.h"
+
+#include <math.h>
+
+#include <algorithm>
+#include <memory>
+#include <set>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "common_audio/include/audio_util.h"
+#include "common_audio/wav_file.h"
+#include "modules/audio_processing/test/conversational_speech/wavreader_interface.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/numerics/safe_conversions.h"
+#include "test/testsupport/file_utils.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+using conversational_speech::MultiEndCall;
+using conversational_speech::SpeakerOutputFilePaths;
+using conversational_speech::WavReaderInterface;
+
+// Combines output path and speaker names to define the output file paths for
+// the near-end and far=end audio tracks.
+std::unique_ptr<std::map<std::string, SpeakerOutputFilePaths>>
+InitSpeakerOutputFilePaths(const std::set<std::string>& speaker_names,
+                           absl::string_view output_path) {
+  // Create map.
+  auto speaker_output_file_paths_map =
+      std::make_unique<std::map<std::string, SpeakerOutputFilePaths>>();
+
+  // Add near-end and far-end output paths into the map.
+  for (const auto& speaker_name : speaker_names) {
+    const std::string near_end_path =
+        test::JoinFilename(output_path, "s_" + speaker_name + "-near_end.wav");
+    RTC_LOG(LS_VERBOSE) << "The near-end audio track will be created in "
+                        << near_end_path << ".";
+
+    const std::string far_end_path =
+        test::JoinFilename(output_path, "s_" + speaker_name + "-far_end.wav");
+    RTC_LOG(LS_VERBOSE) << "The far-end audio track will be created in "
+                        << far_end_path << ".";
+
+    // Add to map.
+    speaker_output_file_paths_map->emplace(
+        std::piecewise_construct, std::forward_as_tuple(speaker_name),
+        std::forward_as_tuple(near_end_path, far_end_path));
+  }
+
+  return speaker_output_file_paths_map;
+}
+
+// Class that provides one WavWriter for the near-end and one for the far-end
+// output track of a speaker.
+class SpeakerWavWriters {
+ public:
+  SpeakerWavWriters(const SpeakerOutputFilePaths& output_file_paths,
+                    int sample_rate)
+      : near_end_wav_writer_(output_file_paths.near_end, sample_rate, 1u),
+        far_end_wav_writer_(output_file_paths.far_end, sample_rate, 1u) {}
+  WavWriter* near_end_wav_writer() { return &near_end_wav_writer_; }
+  WavWriter* far_end_wav_writer() { return &far_end_wav_writer_; }
+
+ private:
+  WavWriter near_end_wav_writer_;
+  WavWriter far_end_wav_writer_;
+};
+
+// Initializes one WavWriter instance for each speaker and both the near-end and
+// far-end output tracks.
+std::unique_ptr<std::map<std::string, SpeakerWavWriters>>
+InitSpeakersWavWriters(const std::map<std::string, SpeakerOutputFilePaths>&
+                           speaker_output_file_paths,
+                       int sample_rate) {
+  // Create map.
+  auto speaker_wav_writers_map =
+      std::make_unique<std::map<std::string, SpeakerWavWriters>>();
+
+  // Add SpeakerWavWriters instance into the map.
+  for (auto it = speaker_output_file_paths.begin();
+       it != speaker_output_file_paths.end(); ++it) {
+    speaker_wav_writers_map->emplace(
+        std::piecewise_construct, std::forward_as_tuple(it->first),
+        std::forward_as_tuple(it->second, sample_rate));
+  }
+
+  return speaker_wav_writers_map;
+}
+
+// Reads all the samples for each audio track.
+std::unique_ptr<std::map<std::string, std::vector<int16_t>>> PreloadAudioTracks(
+    const std::map<std::string, std::unique_ptr<WavReaderInterface>>&
+        audiotrack_readers) {
+  // Create map.
+  auto audiotracks_map =
+      std::make_unique<std::map<std::string, std::vector<int16_t>>>();
+
+  // Add audio track vectors.
+  for (auto it = audiotrack_readers.begin(); it != audiotrack_readers.end();
+       ++it) {
+    // Add map entry.
+    audiotracks_map->emplace(std::piecewise_construct,
+                             std::forward_as_tuple(it->first),
+                             std::forward_as_tuple(it->second->NumSamples()));
+
+    // Read samples.
+    it->second->ReadInt16Samples(audiotracks_map->at(it->first));
+  }
+
+  return audiotracks_map;
+}
+
+// Writes all the values in `source_samples` via `wav_writer`. If the number of
+// previously written samples in `wav_writer` is less than `interval_begin`, it
+// adds zeros as left padding. The padding corresponds to intervals during which
+// a speaker is not active.
+void PadLeftWriteChunk(rtc::ArrayView<const int16_t> source_samples,
+                       size_t interval_begin,
+                       WavWriter* wav_writer) {
+  // Add left padding.
+  RTC_CHECK(wav_writer);
+  RTC_CHECK_GE(interval_begin, wav_writer->num_samples());
+  size_t padding_size = interval_begin - wav_writer->num_samples();
+  if (padding_size != 0) {
+    const std::vector<int16_t> padding(padding_size, 0);
+    wav_writer->WriteSamples(padding.data(), padding_size);
+  }
+
+  // Write source samples.
+  wav_writer->WriteSamples(source_samples.data(), source_samples.size());
+}
+
+// Appends zeros via `wav_writer`. The number of zeros is always non-negative
+// and equal to the difference between the previously written samples and
+// `pad_samples`.
+void PadRightWrite(WavWriter* wav_writer, size_t pad_samples) {
+  RTC_CHECK(wav_writer);
+  RTC_CHECK_GE(pad_samples, wav_writer->num_samples());
+  size_t padding_size = pad_samples - wav_writer->num_samples();
+  if (padding_size != 0) {
+    const std::vector<int16_t> padding(padding_size, 0);
+    wav_writer->WriteSamples(padding.data(), padding_size);
+  }
+}
+
+void ScaleSignal(rtc::ArrayView<const int16_t> source_samples,
+                 int gain,
+                 rtc::ArrayView<int16_t> output_samples) {
+  const float gain_linear = DbToRatio(gain);
+  RTC_DCHECK_EQ(source_samples.size(), output_samples.size());
+  std::transform(source_samples.begin(), source_samples.end(),
+                 output_samples.begin(), [gain_linear](int16_t x) -> int16_t {
+                   return rtc::saturated_cast<int16_t>(x * gain_linear);
+                 });
+}
+
+}  // namespace
+
+namespace conversational_speech {
+
+std::unique_ptr<std::map<std::string, SpeakerOutputFilePaths>> Simulate(
+    const MultiEndCall& multiend_call,
+    absl::string_view output_path) {
+  // Set output file paths and initialize wav writers.
+  const auto& speaker_names = multiend_call.speaker_names();
+  auto speaker_output_file_paths =
+      InitSpeakerOutputFilePaths(speaker_names, output_path);
+  auto speakers_wav_writers = InitSpeakersWavWriters(
+      *speaker_output_file_paths, multiend_call.sample_rate());
+
+  // Preload all the input audio tracks.
+  const auto& audiotrack_readers = multiend_call.audiotrack_readers();
+  auto audiotracks = PreloadAudioTracks(audiotrack_readers);
+
+  // TODO(alessiob): When speaker_names.size() == 2, near-end and far-end
+  // across the 2 speakers are symmetric; hence, the code below could be
+  // replaced by only creating the near-end or the far-end. However, this would
+  // require to split the unit tests and document the behavior in README.md.
+  // In practice, it should not be an issue since the files are not expected to
+  // be signinificant.
+
+  // Write near-end and far-end output tracks.
+  for (const auto& speaking_turn : multiend_call.speaking_turns()) {
+    const std::string& active_speaker_name = speaking_turn.speaker_name;
+    const auto source_audiotrack =
+        audiotracks->at(speaking_turn.audiotrack_file_name);
+    std::vector<int16_t> scaled_audiotrack(source_audiotrack.size());
+    ScaleSignal(source_audiotrack, speaking_turn.gain, scaled_audiotrack);
+
+    // Write active speaker's chunk to active speaker's near-end.
+    PadLeftWriteChunk(
+        scaled_audiotrack, speaking_turn.begin,
+        speakers_wav_writers->at(active_speaker_name).near_end_wav_writer());
+
+    // Write active speaker's chunk to other participants' far-ends.
+    for (const std::string& speaker_name : speaker_names) {
+      if (speaker_name == active_speaker_name)
+        continue;
+      PadLeftWriteChunk(
+          scaled_audiotrack, speaking_turn.begin,
+          speakers_wav_writers->at(speaker_name).far_end_wav_writer());
+    }
+  }
+
+  // Finalize all the output tracks with right padding.
+  // This is required to make all the output tracks duration equal.
+  size_t duration_samples = multiend_call.total_duration_samples();
+  for (const std::string& speaker_name : speaker_names) {
+    PadRightWrite(speakers_wav_writers->at(speaker_name).near_end_wav_writer(),
+                  duration_samples);
+    PadRightWrite(speakers_wav_writers->at(speaker_name).far_end_wav_writer(),
+                  duration_samples);
+  }
+
+  return speaker_output_file_paths;
+}
+
+}  // namespace conversational_speech
+}  // namespace test
+}  // namespace webrtc