Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/frame_blocker.h

Index: webrtc/modules/audio_processing/aec3/frame_blocker.h
diff --git a/webrtc/modules/audio_processing/aec3/frame_blocker.h b/webrtc/modules/audio_processing/aec3/frame_blocker.h
new file mode 100644
index 0000000000000000000000000000000000000000..18f3d511047796fb029e155c14eb700da1b0b2b6
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/frame_blocker.h
@@ -0,0 +1,51 @@
+/*
+ *  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_FRAME_BLOCKER_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_FRAME_BLOCKER_H_
+
+#include <stddef.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 64 sample multiband blocks from 10 ms frames */

[hlundin-webrtc, 2016/12/16 10:04:47]

// style

[peah-webrtc, 2016/12/20 10:10:26]

Done.

+class FrameBlocker {
+ public:
+  explicit FrameBlocker(size_t num_bands, size_t frame_length);

[hlundin-webrtc, 2016/12/16 10:04:47]

Drop 'explicit'.

[peah-webrtc, 2016/12/20 10:10:26]

Done.

+  ~FrameBlocker();
+  void InsertFrameAndExtractBlock(size_t sub_frame_index,
+                                  rtc::ArrayView<const float> frame,
+                                  rtc::ArrayView<float> block);
+  void InsertFrameAndExtractBlock(size_t sub_frame_index,
+                                  const float* const* frame,
+                                  rtc::ArrayView<float> block);
+  bool IsBlockAvailable();
+  bool ExtractBlockIfAvailable(rtc::ArrayView<float> block);
+
+ private:
+  const size_t num_bands_;
+  const size_t frame_length_;
+  std::vector<float> buffer_;

[aleloi, 2016/12/16 15:04:31]

I think the copying and indexing in *ExtractBlock* will be simpler if there is
one buffer for every band.

[ivoc, 2016/12/19 11:30:22]

Perhaps there could even be a subclass to handle one of these buffers, with
methods for inserting and extracting.

[peah-webrtc, 2016/12/20 10:10:26]

Agree. I did it now as hundin@ suggested with a vector of vectors.

Done.

[peah-webrtc, 2016/12/20 10:10:26]

That would definitely make sense and the initial version (before this CL) had a
specific class for that. However, the benefits of vectors outweigh that, I
think, and with the new patch I think the code is in a better state.

WDYT?

+  size_t buffer_size_ = 0;
+
+  void InsertFrameAndExtractBlock(

[hlundin-webrtc, 2016/12/16 10:04:47]

Methods before data members.

[peah-webrtc, 2016/12/20 10:10:26]

Done.

+      rtc::ArrayView<const rtc::ArrayView<const float>> frame,
+      rtc::ArrayView<float> block);
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(FrameBlocker);
+};
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_FRAME_BLOCKER_H_