Conversational Speech tool, MultiEndCall::CheckTiming() and tests

webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc

Index: webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
index f16aa753fa427a42b7def1298c145a52f3154afd..ad1d9a0c87e90d9dc4c398bc21d120673379c366 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
+++ b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
@@ -10,8 +10,10 @@
 
 #include "webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h"
 
-#include <utility>
+#include <algorithm>
+#include <iterator>
 
+#include "webrtc/base/logging.h"
 #include "webrtc/base/pathutils.h"
 
 namespace webrtc {
@@ -25,7 +27,7 @@ MultiEndCall::MultiEndCall(
           wavreader_abstract_factory_(std::move(wavreader_abstract_factory)) {
   FindSpeakerNames();
   CreateAudioTrackReaders();
-  CheckTiming();
+  valid_ = CheckTiming();
 }
 
 MultiEndCall::~MultiEndCall() = default;
@@ -39,10 +41,23 @@ const std::map<std::string, std::unique_ptr<WavReaderInterface>>&
   return audiotrack_readers_;
 }
 
+bool MultiEndCall::valid() const {
+  return valid_;
+}
+
+size_t MultiEndCall::total_duration_samples() const {
+  return total_duration_samples_;
+}
+
+const std::vector<MultiEndCall::SpeakingTurn>& MultiEndCall::speaking_turns()
+    const {
+  return speaking_turns_;
+}
+
 void MultiEndCall::FindSpeakerNames() {
   RTC_DCHECK(speaker_names_.empty());
   for (const Turn& turn : timing_) {
-    speaker_names_.insert(turn.speaker_name);
+    speaker_names_.emplace(turn.speaker_name);
   }
 }
 
@@ -60,14 +75,119 @@ void MultiEndCall::CreateAudioTrackReaders() {
     // Map the audiotrack file name to a new instance of WavReaderInterface.
     std::unique_ptr<WavReaderInterface> wavreader =
         wavreader_abstract_factory_->Create(audiotrack_file_path.pathname());
-    audiotrack_readers_.insert(std::make_pair(
-        turn.audiotrack_file_name, std::move(wavreader)));
+    audiotrack_readers_.emplace(
+        turn.audiotrack_file_name, std::move(wavreader));
   }
 }
 
-void MultiEndCall::CheckTiming() {
-  // TODO(alessiob): use audiotrack lengths and offset to check whether the
-  // timing is valid.
+bool MultiEndCall::CheckTiming() {
+  struct Interval {
+    size_t begin;
+    size_t end;
+  };
+  size_t number_of_turns = timing_.size();
+  auto millisecond_to_samples = [](int ms, int sr) -> int {
+    // Truncation may happen if the sampling rate is not an integer multiple
+    // of 1000 (e.g., 44100).
+    return ms * sr / 1000;
+  };
+  auto in_interval = [](size_t value, const Interval& interval) {
+    return interval.begin <= value && value < interval.end;
+  };
+  total_duration_samples_ = 0;
+  speaking_turns_.clear();
+
+  // Begin and end timestamps for the last two turns (unit: number of samples).
+  Interval second_last_turn = {0, 0};
+  Interval last_turn = {0, 0};
+
+  // Initialize map to store speaking turn indices of each speaker (used to
+  // detect self cross-talk).
+  std::map<std::string, std::vector<size_t>> speaking_turn_indices;
+  for (const std::string& speaker_name : speaker_names_) {
+    speaking_turn_indices.emplace(
+        std::piecewise_construct,
+        std::forward_as_tuple(speaker_name),
+        std::forward_as_tuple());
+  }
+
+  // Parse turns.
+  for (size_t turn_index = 0; turn_index < number_of_turns; ++turn_index) {
+    const Turn& turn = timing_[turn_index];
+    auto it = audiotrack_readers_.find(turn.audiotrack_file_name);
+    RTC_CHECK(it != audiotrack_readers_.end())
+        << "Audio track reader not created";
+
+    // Begin and end timestamps for the current turn.
+    int offset_samples = millisecond_to_samples(
+        turn.offset, it->second->sample_rate());
+    size_t begin_timestamp = last_turn.end + offset_samples;
+    size_t end_timestamp = begin_timestamp + it->second->num_samples();
+    LOG(LS_INFO) << "turn #" << turn_index << " " << begin_timestamp
+        << "-" << end_timestamp << " ms";
+
+    // The order is invalid if the offset is negative and its absolute value is
+    // larger then the duration of the previous turn.
+    if (offset_samples < 0 && -offset_samples > static_cast<int>(
+        last_turn.end - last_turn.begin)) {
+      LOG(LS_ERROR) << "invalid order";
+      return false;
+    }
+
+    // Cross-talk with 3 or more speakers occurs when the beginning of the
+    // current interval falls in the last two turns.
+    if (turn_index > 1 && in_interval(begin_timestamp, last_turn)
+        && in_interval(begin_timestamp, second_last_turn)) {
+      LOG(LS_ERROR) << "cross-talk with 3+ speakers";
+      return false;
+    }
+
+    // Append turn.
+    speaking_turns_.emplace_back(
+        turn.speaker_name, turn.audiotrack_file_name,
+        begin_timestamp, end_timestamp);
+
+    // Save speaking turn index for self cross-talk detection.
+    RTC_DCHECK_EQ(speaking_turns_.size(), turn_index + 1);
+    speaking_turn_indices[turn.speaker_name].push_back(turn_index);
+
+    // Update total duration of the consversational speech.
+    if (total_duration_samples_ < end_timestamp)
+      total_duration_samples_ = end_timestamp;
+
+    // Update and continue with next turn.
+    second_last_turn = last_turn;
+    last_turn.begin = begin_timestamp;
+    last_turn.end = end_timestamp;
+  }
+
+  // Detect self cross-talk.
+  for (const std::string& speaker_name : speaker_names_) {
+    LOG(LS_INFO) << "checking self cross-talk for <"
+        << speaker_name << ">";
+
+    // Copy all turns for this speaker to new vector.
+    std::vector<SpeakingTurn> speaking_turns_for_name;
+    std::copy_if(speaking_turns_.begin(), speaking_turns_.end(),
+                 std::back_inserter(speaking_turns_for_name),
+                 [&speaker_name](const SpeakingTurn& st){
+                   return st.speaker_name == speaker_name; });
+
+    // Check for overlap between adjacent elements.
+    // This is a sufficient condition for self cross-talk since the intervals
+    // are sorted by begin timestamp.
+    auto overlap = std::adjacent_find(
+        speaking_turns_for_name.begin(), speaking_turns_for_name.end(),
+        [](const SpeakingTurn& a, const SpeakingTurn& b) {
+            return a.end > b.begin; });
+
+    if (overlap != speaking_turns_for_name.end()) {
+      LOG(LS_ERROR) << "Self cross-talk detected";
+      return false;
+    }
+  }
+
+  return true;
 }
 
 }  // namespace conversational_speech