Add LoudestFilter in ConferenceTransport

webrtc/voice_engine/test/auto_test/fakes/loudest_filter.cc

Index: webrtc/voice_engine/test/auto_test/fakes/loudest_filter.cc
diff --git a/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.cc b/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..29dda630d7add6f8b5c8fa7dd87a55905d9ce4e5
--- /dev/null
+++ b/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.cc
@@ -0,0 +1,82 @@
+/*
+ *  Copyright (c) 2015 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 "webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h"
+
+#include "webrtc/base/checks.h"
+
+namespace voetest {
+
+void LoudestFilter::RemoveTimeoutStreams(uint32 time_ms) {
+  auto it = stream_levels_.begin();
+  while (it != stream_levels_.end()) {
+    if (rtc::TimeDiff(time_ms, it->second.last_time_ms) >
+        kStreamTimeOutMs) {
+      stream_levels_.erase(it++);
+    } else {
+      ++it;
+    }
+  }
+}
+
+unsigned int LoudestFilter::FindQuietestStream() {
+  int quietest_level = kInvalidAudioLevel;
+  unsigned int quietest_ssrc = 0;
+  for (auto stream : stream_levels_) {
+    // A smaller value if audio level corresponds to a louder sound.
+    if (quietest_level == kInvalidAudioLevel ||
+        stream.second.audio_level > quietest_level) {
+      quietest_level = stream.second.audio_level;
+      quietest_ssrc = stream.first;
+    }
+  }
+  return quietest_ssrc;
+}
+
+bool LoudestFilter::ForwardThisPacket(const webrtc::RTPHeader& rtp_header) {
+  uint32 time_now_ms = rtc::Time();
+  RemoveTimeoutStreams(time_now_ms);
+
+  int source_ssrc = rtp_header.ssrc;
+  int audio_level = rtp_header.extension.hasAudioLevel ?
+      rtp_header.extension.audioLevel : kInvalidAudioLevel;
+
+  if (audio_level == kInvalidAudioLevel) {
+    // Always forward streams with unknown audio level, and don't keep their
+    // states.
+    return true;
+  }
+
+  auto it = stream_levels_.find(source_ssrc);
+  if (it != stream_levels_.end()) {
+    // Stream has been forwarded. Update and continue to forward.
+    it->second.audio_level = audio_level;
+    it->second.last_time_ms = time_now_ms;
+    return true;
+  }
+
+  if (stream_levels_.size() < kMaxMixSize) {
+    stream_levels_[source_ssrc].Set(audio_level, time_now_ms);
+    return true;
+  }
+
+  unsigned int quietest_ssrc = FindQuietestStream();
+  CHECK_NE(0u, quietest_ssrc);
+  // A smaller value if audio level corresponds to a louder sound.
+  if (audio_level < stream_levels_[quietest_ssrc].audio_level) {
+    stream_levels_.erase(quietest_ssrc);
+    stream_levels_[source_ssrc].Set(audio_level, time_now_ms);
+    return true;
+  }
+  return false;
+}
+
+}  // namespace voetest
+