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/*
* Copyright (C) 2013 Google Inc. All rights reserved.
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* modification, are permitted provided that the following conditions are
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* * Redistributions of source code must retain the above copyright
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* in the documentation and/or other materials provided with the
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_UP_SAMPLER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_UP_SAMPLER_H_
#include <memory>
#include "base/macros.h"
#include "third_party/blink/renderer/platform/audio/audio_array.h"
#include "third_party/blink/renderer/platform/audio/direct_convolver.h"
#include "third_party/blink/renderer/platform/audio/simple_fft_convolver.h"
#include "third_party/blink/renderer/platform/wtf/allocator.h"
namespace blink {
// UpSampler up-samples the source stream by a factor of 2x.
class PLATFORM_EXPORT UpSampler {
USING_FAST_MALLOC(UpSampler);
public:
explicit UpSampler(size_t input_block_size);
// The destination buffer |destP| is of size sourceFramesToProcess * 2.
void Process(const float* source_p,
float* dest_p,
size_t source_frames_to_process);
void Reset();
// Latency based on the source sample-rate.
size_t LatencyFrames() const;
private:
enum { kDefaultKernelSize = 128 };
size_t input_block_size_;
// Computes the odd sample-frames of the output.
std::unique_ptr<DirectConvolver> direct_convolver_;
std::unique_ptr<SimpleFFTConvolver> simple_fft_convolver_;
AudioFloatArray temp_buffer_;
// Delay line for generating the even sample-frames of the output.
// The source samples are delayed exactly to match the linear phase delay of
// the FIR filter (convolution) used to generate the odd sample-frames of the
// output.
AudioFloatArray input_buffer_;
DISALLOW_COPY_AND_ASSIGN(UpSampler);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_UP_SAMPLER_H_