Merge from Chromium at DEPS revision r167172

This commit was generated by merge_to_master.py.

Change-Id: Ib8d56fd5ae39a2d7e8c91dcd76cc6d13f25f2aab

1 files changed, 100 insertions, 0 deletions

diff --git a/media/base/sinc_resampler.h b/media/base/sinc_resampler.h
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+++ b/media/base/sinc_resampler.h
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_SINC_RESAMPLER_H_
+#define MEDIA_BASE_SINC_RESAMPLER_H_
+
+#include "base/callback.h"
+#include "base/gtest_prod_util.h"
+#include "base/memory/aligned_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+// SincResampler is a high-quality single-channel sample-rate converter.
+class MEDIA_EXPORT SincResampler {
+ public:
+  // The maximum number of samples that may be requested from the callback ahead
+  // of the current position in the stream.
+  static const int kMaximumLookAheadSize;
+
+  // Callback type for providing more data into the resampler.  Expects |frames|
+  // of data to be rendered into |destination|; zero padded if not enough frames
+  // are available to satisfy the request.
+  typedef base::Callback<void(float* destination, int frames)> ReadCB;
+
+  // Constructs a SincResampler with the specified |read_cb|, which is used to
+  // acquire audio data for resampling.  |io_sample_rate_ratio| is the ratio of
+  // input / output sample rates.
+  SincResampler(double io_sample_rate_ratio, const ReadCB& read_cb);
+  virtual ~SincResampler();
+
+  // Resample |frames| of data from |read_cb_| into |destination|.
+  void Resample(float* destination, int frames);
+
+  // The maximum size in frames that guarantees Resample() will only make a
+  // single call to |read_cb_| for more data.
+  int ChunkSize();
+
+  // Flush all buffered data and reset internal indices.
+  void Flush();
+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
+  FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
+
+  void InitializeKernel();
+
+  // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
+  // linearly interpolated using |kernel_interpolation_factor|.  On x86, the
+  // underlying implementation is chosen at run time based on SSE support.  On
+  // ARM, NEON support is chosen at compile time based on compilation flags.
+  static float Convolve(const float* input_ptr, const float* k1,
+                        const float* k2, double kernel_interpolation_factor);
+  static float Convolve_C(const float* input_ptr, const float* k1,
+                          const float* k2, double kernel_interpolation_factor);
+  static float Convolve_SSE(const float* input_ptr, const float* k1,
+                            const float* k2,
+                            double kernel_interpolation_factor);
+  static float Convolve_NEON(const float* input_ptr, const float* k1,
+                             const float* k2,
+                             double kernel_interpolation_factor);
+
+  // The ratio of input / output sample rates.
+  double io_sample_rate_ratio_;
+
+  // An index on the source input buffer with sub-sample precision.  It must be
+  // double precision to avoid drift.
+  double virtual_source_idx_;
+
+  // The buffer is primed once at the very beginning of processing.
+  bool buffer_primed_;
+
+  // Source of data for resampling.
+  ReadCB read_cb_;
+
+  // Contains kKernelOffsetCount kernels back-to-back, each of size kKernelSize.
+  // The kernel offsets are sub-sample shifts of a windowed sinc shifted from
+  // 0.0 to 1.0 sample.
+  scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> kernel_storage_;
+
+  // Data from the source is copied into this buffer for each processing pass.
+  scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> input_buffer_;
+
+  // Pointers to the various regions inside |input_buffer_|.  See the diagram at
+  // the top of the .cc file for more information.
+  float* const r0_;
+  float* const r1_;
+  float* const r2_;
+  float* const r3_;
+  float* const r4_;
+  float* const r5_;
+
+  DISALLOW_COPY_AND_ASSIGN(SincResampler);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_SINC_RESAMPLER_H_