8fc05feed4
Includes a unittest to ensure we meet the same quality thresholds as SincResampler (modulo quantization error). BUG=webrtc:1395 Review URL: https://webrtc-codereview.appspot.com/1323011 git-svn-id: http://webrtc.googlecode.com/svn/trunk@3909 4adac7df-926f-26a2-2b94-8c16560cd09d
124 lines
4.5 KiB
C++
124 lines
4.5 KiB
C++
/*
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* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// Modified from the Chromium original here:
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// src/media/base/sinc_resampler.h
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#ifndef WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
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#define WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
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#include "webrtc/system_wrappers/interface/aligned_malloc.h"
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#include "webrtc/system_wrappers/interface/constructor_magic.h"
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#include "webrtc/system_wrappers/interface/scoped_ptr.h"
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#include "webrtc/test/testsupport/gtest_prod_util.h"
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namespace webrtc {
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// Callback class to provide SincResampler with input.
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class SincResamplerCallback {
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public:
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virtual ~SincResamplerCallback() {}
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virtual void Run(float* destination, int frames) = 0;
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};
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// SincResampler is a high-quality single-channel sample-rate converter.
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class SincResampler {
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public:
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// Constructs a SincResampler with the specified |read_cb|, which is used to
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// acquire audio data for resampling. |io_sample_rate_ratio| is the ratio of
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// input / output sample rates. If desired, the number of destination frames
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// generated per processing pass can be specified through |block_size|.
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SincResampler(double io_sample_rate_ratio,
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SincResamplerCallback* read_cb);
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SincResampler(double io_sample_rate_ratio,
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SincResamplerCallback* read_cb,
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int block_size);
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virtual ~SincResampler();
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// Resample |frames| of data from |read_cb_| into |destination|.
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void Resample(float* destination, int frames);
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// The maximum size in frames that guarantees Resample() will only make a
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// single call to |read_cb_| for more data.
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int ChunkSize();
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// The number of source frames requested per processing pass (and equal to
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// |block_size| if provided at construction). The first pass will request
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// more to prime the buffer.
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int BlockSize();
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// Flush all buffered data and reset internal indices.
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void Flush();
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private:
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FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
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FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
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void Initialize();
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void InitializeKernel();
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// Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
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// linearly interpolated using |kernel_interpolation_factor|. On x86, the
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// underlying implementation is chosen at run time based on SSE support. On
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// ARM, NEON support is chosen at compile time based on compilation flags.
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static float Convolve(const float* input_ptr, const float* k1,
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const float* k2, double kernel_interpolation_factor);
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static float Convolve_C(const float* input_ptr, const float* k1,
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const float* k2, double kernel_interpolation_factor);
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static float Convolve_SSE(const float* input_ptr, const float* k1,
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const float* k2,
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double kernel_interpolation_factor);
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static float Convolve_NEON(const float* input_ptr, const float* k1,
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const float* k2,
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double kernel_interpolation_factor);
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// The ratio of input / output sample rates.
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double io_sample_rate_ratio_;
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// An index on the source input buffer with sub-sample precision. It must be
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// double precision to avoid drift.
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double virtual_source_idx_;
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// The buffer is primed once at the very beginning of processing.
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bool buffer_primed_;
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// Source of data for resampling.
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SincResamplerCallback* read_cb_;
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// See kDefaultBlockSize.
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int block_size_;
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// See kDefaultBufferSize.
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int buffer_size_;
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// Contains kKernelOffsetCount kernels back-to-back, each of size kKernelSize.
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// The kernel offsets are sub-sample shifts of a windowed sinc shifted from
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// 0.0 to 1.0 sample.
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scoped_ptr_malloc<float, AlignedFree> kernel_storage_;
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// Data from the source is copied into this buffer for each processing pass.
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scoped_ptr_malloc<float, AlignedFree> input_buffer_;
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// Pointers to the various regions inside |input_buffer_|. See the diagram at
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// the top of the .cc file for more information.
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float* const r0_;
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float* const r1_;
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float* const r2_;
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float* const r3_;
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float* const r4_;
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float* const r5_;
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DISALLOW_COPY_AND_ASSIGN(SincResampler);
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};
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} // namespace webrtc
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#endif // WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
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