/*
* Copyright (C) 2013 Google Inc. All rights reserved.
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#ifndef UpSampler_h
#define UpSampler_h
#include "platform/audio/AudioArray.h"
#include "platform/audio/DirectConvolver.h"
namespace WebCore {
// UpSampler up-samples the source stream by a factor of 2x.
class PLATFORM_EXPORT UpSampler {
public:
UpSampler(size_t inputBlockSize);
// The destination buffer |destP| is of size sourceFramesToProcess * 2.
void process(const float* sourceP, float* destP, size_t sourceFramesToProcess);
void reset();
// Latency based on the source sample-rate.
size_t latencyFrames() const;
private:
enum { DefaultKernelSize = 128 };
size_t m_inputBlockSize;
// Computes ideal band-limited filter coefficients to sample in between each source sample-frame.
// This filter will be used to compute the odd sample-frames of the output.
void initializeKernel();
AudioFloatArray m_kernel;
// Computes the odd sample-frames of the output.
DirectConvolver m_convolver;
AudioFloatArray m_tempBuffer;
// 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 m_inputBuffer;
};
} // namespace WebCore
#endif // UpSampler_h