Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/block_framer.h

+/*
+ *  Copyright (c) 2016 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_MODULES_AUDIO_PROCESSING_AEC3_BLOCK_FRAMER_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_BLOCK_FRAMER_H_
+
+#include <vector>
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+
+namespace webrtc {
+
+// Class for producing frames consisting of 1 or 2 subframes of 80 samples each
+// from 64 sample blocks. The class is designed to work together with the
+// FrameBlocker class which performs the reverse conversion. Used together with
+// that, this class produces output frames are the same rate as frames are
+// received by the FrameBlocker class. Note that the internal buffers will
+// overrun if any other rate of packets insertion is used.
+class BlockFramer {
+ public:
+  explicit BlockFramer(size_t num_bands);
+  ~BlockFramer();
+  // Adds a 64 sample block into the data that will form the next output frame.
+  void InsertBlock(const std::vector<std::vector<float>>& block);
+  // Adds a 64 sample block and extracts an 80 sample subframe.
+  void InsertBlockAndExtractSubFrame(
+      const std::vector<std::vector<float>>& block,
+      std::vector<rtc::ArrayView<float>>* sub_frame);
+
+ private:
+  const size_t num_bands_;
+  std::vector<std::vector<float>> buffer_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(BlockFramer);
+};
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_BLOCK_FRAMER_H_