Import LappedTransform and friends.

Add code for doing block-based frequency domain processing. Developed
and reviewed in isolation. Corresponding export CL:
https://chromereviews.googleplex.com/95187013/

R=bercic@google.com, kjellander@webrtc.org, turaj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31539004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@7359 4adac7df-926f-26a2-2b94-8c16560cd09d

1 files changed, 174 insertions, 0 deletions

diff --git a/common_audio/lapped_transform_unittest.cc b/common_audio/lapped_transform_unittest.cc
new file mode 100644
index 00000000..90523822
--- /dev/null
+++ b/common_audio/lapped_transform_unittest.cc
@@ -0,0 +1,174 @@
+/*
+ *  Copyright (c) 2014 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/common_audio/lapped_transform.h"
+
+#include <cmath>
+#include <cstring>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+using std::complex;
+
+namespace {
+
+class NoopCallback : public webrtc::LappedTransform::Callback {
+ public:
+  NoopCallback() : block_num_(0) {}
+
+  virtual void ProcessAudioBlock(const complex<float>* const* in_block,
+                                 int in_channels, int frames, int out_channels,
+                                 complex<float>* const* out_block) {
+    CHECK_EQ(in_channels, out_channels);
+    for (int i = 0; i < out_channels; ++i) {
+      memcpy(out_block[i], in_block[i], sizeof(**in_block) * frames);
+    }
+    ++block_num_;
+  }
+
+  int block_num() {
+    return block_num_;
+  }
+
+ private:
+  int block_num_;
+};
+
+class FftCheckerCallback : public webrtc::LappedTransform::Callback {
+ public:
+  FftCheckerCallback() : block_num_(0) {}
+
+  virtual void ProcessAudioBlock(const complex<float>* const* in_block,
+                                 int in_channels, int frames, int out_channels,
+                                 complex<float>* const* out_block) {
+    CHECK_EQ(in_channels, out_channels);
+
+    float full_length = (frames - 1) * 2;
+    ++block_num_;
+
+    if (block_num_ == 1) {
+      for (int i = 0; i < frames; ++i) {
+        ASSERT_NEAR(in_block[0][i].real(), 0.0f, 1e-5f);
+        ASSERT_NEAR(in_block[0][i].imag(), 0.0f, 1e-5f);
+      }
+    } else {
+      ASSERT_NEAR(in_block[0][0].real(), full_length, 1e-5f);
+      ASSERT_NEAR(in_block[0][0].imag(), 0.0f, 1e-5f);
+      for (int i = 1; i < frames; ++i) {
+        ASSERT_NEAR(in_block[0][i].real(), 0.0f, 1e-5f);
+        ASSERT_NEAR(in_block[0][i].imag(), 0.0f, 1e-5f);
+      }
+    }
+  }
+
+  int block_num() {
+    return block_num_;
+  }
+
+ private:
+  int block_num_;
+};
+
+void SetFloatArray(float value, int rows, int cols, float* const* array) {
+  for (int i = 0; i < rows; ++i) {
+    for (int j = 0; j < cols; ++j) {
+      array[i][j] = value;
+    }
+  }
+}
+
+}  // namespace
+
+namespace webrtc {
+
+TEST(LappedTransformTest, Windowless) {
+  const int kChannels = 3;
+  const int kChunkLength = 512;
+  const int kBlockLength = 64;
+  const int kShiftAmount = 32;
+  NoopCallback noop;
+  LappedTransform trans(kChannels, kChannels, kChunkLength, nullptr,
+                        kBlockLength, kShiftAmount, &noop);
+  float in_buffer[kChannels][kChunkLength];
+  float* in_chunk[kChannels];
+  float out_buffer[kChannels][kChunkLength];
+  float* out_chunk[kChannels];
+
+  in_chunk[0] = in_buffer[0];
+  in_chunk[1] = in_buffer[1];
+  in_chunk[2] = in_buffer[2];
+  out_chunk[0] = out_buffer[0];
+  out_chunk[1] = out_buffer[1];
+  out_chunk[2] = out_buffer[2];
+  SetFloatArray(2.0f, kChannels, kChunkLength, in_chunk);
+  SetFloatArray(-1.0f, kChannels, kChunkLength, out_chunk);
+
+  trans.ProcessChunk(in_chunk, out_chunk);
+
+  for (int i = 0; i < kChannels; ++i) {
+    for (int j = 0; j < kChunkLength; ++j) {
+      ASSERT_NEAR(out_chunk[i][j], (j < kBlockLength) ? 0.0f : 2.0f, 1e-5f);
+    }
+  }
+
+  ASSERT_EQ(kChunkLength / kBlockLength, noop.block_num());
+}
+
+TEST(LappedTransformTest, IdentityProcessor) {
+  const int kChunkLength = 512;
+  const int kBlockLength = 64;
+  const int kShiftAmount = 32;
+  NoopCallback noop;
+  float window[kBlockLength];
+  float* window_ptr = window;
+
+  // Identity window for |overlap = block_size / 2|.
+  SetFloatArray(sqrtf(0.5f), 1, kBlockLength, &window_ptr);
+
+  LappedTransform trans(1, 1, kChunkLength, window, kBlockLength, kShiftAmount,
+                        &noop);
+  float in_buffer[kChunkLength];
+  float* in_chunk = in_buffer;
+  float out_buffer[kChunkLength];
+  float* out_chunk = out_buffer;
+
+  SetFloatArray(2.0f, 1, kChunkLength, &in_chunk);
+  SetFloatArray(-1.0f, 1, kChunkLength, &out_chunk);
+
+  trans.ProcessChunk(&in_chunk, &out_chunk);
+
+  for (int i = 0; i < kChunkLength; ++i) {
+    ASSERT_NEAR(out_chunk[i], (i < kBlockLength) ? 0.0f : 2.0f, 1e-5f);
+  }
+
+  ASSERT_EQ(kChunkLength / kShiftAmount, noop.block_num());
+}
+
+TEST(LappedTransformTest, Callbacks) {
+  const int kChunkLength = 512;
+  const int kBlockLength = 64;
+  FftCheckerCallback call;
+  LappedTransform trans(1, 1, kChunkLength, nullptr, kBlockLength,
+                        kBlockLength, &call);
+  float in_buffer[kChunkLength];
+  float* in_chunk = in_buffer;
+  float out_buffer[kChunkLength];
+  float* out_chunk = out_buffer;
+
+  SetFloatArray(1.0f, 1, kChunkLength, &in_chunk);
+  SetFloatArray(-1.0f, 1, kChunkLength, &out_chunk);
+
+  trans.ProcessChunk(&in_chunk, &out_chunk);
+
+  ASSERT_EQ(kChunkLength / kBlockLength, call.block_num());
+}
+
+}  // namespace webrtc
+