Add LoudestFilter in ConferenceTransport

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

Index: webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h
diff --git a/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h b/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..e394a6b801f960b0e59b29bdbdd4b8b5b03bbee6
--- /dev/null
+++ b/webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h
@@ -0,0 +1,54 @@
+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_VOICE_ENGINE_TEST_AUTO_TEST_FAKES_LOUDEST_FILTER_H_
+#define WEBRTC_VOICE_ENGINE_TEST_AUTO_TEST_FAKES_LOUDEST_FILTER_H_
+
+#include <map>
+#include "webrtc/base/timeutils.h"
+#include "webrtc/common_types.h"
+
+namespace voetest {
+
+class LoudestFilter {
+ public:
+  /* DecideForward()
+   * Decide whether to pass a RTP packet, given its header.
+   *
+   * Input:
+   *   rtp_header : Header of the RTP packet of interest.
+   */
+  bool IfPassRtpPacket(const webrtc::RTPHeader& rtp_header);

[phoglund, 2015/08/12 15:01:23]

Hmm. This sounds like the if statement is somehow embedded into the method (i.e.
that it should call a callback when the predicate is true or something?

I liked hlundin's ForwardThisPacket. Yeah, arguably forwarding as a concept
isn't very related to filters, but I can't think of anything better.

Also, update the comment.

[hlundin-webrtc, 2015/08/13 07:11:12]

Virtual egg thrown. I agree with phoglund, to agree with my own suggestion. :)

Yes, "forwarding" is maybe not a typical operation of a filter, but I'd turn the
argument around and ask if what you are implementing really is a filter, or is
it a selective packet router? Note: not arguing that you should change he name
of the class.

[minyue-webrtc, 2015/08/13 11:31:15]

Done.

[minyue-webrtc, 2015/08/13 11:31:15]

Done.

+
+ private:
+  struct Status {
+    void Set(int audio_level, uint32 last_time_ms) {
+      this->audio_level = audio_level;
+      this->last_time_ms = last_time_ms;
+    }
+    int audio_level;
+    uint32 last_time_ms;
+  };
+
+  void RemoveTimeoutStreams(uint32 time_ms);
+  unsigned int FindQuietestStream();
+
+  // Keeps the streams being forwarded in pair<SSRC, Status>.
+  std::map<unsigned int, Status> stream_levels_;
+
+  const int32 kStreamTimeOutMs = 5000;
+  const size_t kMaxMixSize = 3;
+  const int kInvalidAudioLevel = 128;
+};
+
+
+}  // namespace voetest
+
+#endif  // WEBRTC_VOICE_ENGINE_TEST_AUTO_TEST_FAKES_LOUDEST_FILTER_H_