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/*
* Copyright (c) 2011 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.
*/
/*
* A wrapper for resampling a numerous amount of sampling combinations.
*/
#ifndef COMMON_AUDIO_RESAMPLER_INCLUDE_RESAMPLER_H_
#define COMMON_AUDIO_RESAMPLER_INCLUDE_RESAMPLER_H_
#include <stddef.h>
#include <stdint.h>
namespace webrtc {
// All methods return 0 on success and -1 on failure.
class Resampler {
public:
Resampler();
Resampler(int inFreq, int outFreq, size_t num_channels);
~Resampler();
// Reset all states
int Reset(int inFreq, int outFreq, size_t num_channels);
// Reset all states if any parameter has changed
int ResetIfNeeded(int inFreq, int outFreq, size_t num_channels);
// Resample samplesIn to samplesOut.
int Push(const int16_t* samplesIn,
size_t lengthIn,
int16_t* samplesOut,
size_t maxLen,
size_t& outLen); // NOLINT: to avoid changing APIs
private:
enum ResamplerMode {
kResamplerMode1To1,
kResamplerMode1To2,
kResamplerMode1To3,
kResamplerMode1To4,
kResamplerMode1To6,
kResamplerMode1To12,
kResamplerMode2To3,
kResamplerMode2To11,
kResamplerMode4To11,
kResamplerMode8To11,
kResamplerMode11To16,
kResamplerMode11To32,
kResamplerMode2To1,
kResamplerMode3To1,
kResamplerMode4To1,
kResamplerMode6To1,
kResamplerMode12To1,
kResamplerMode3To2,
kResamplerMode11To2,
kResamplerMode11To4,
kResamplerMode11To8
};
// Computes the resampler mode for a given sampling frequency pair.
// Returns -1 for unsupported frequency pairs.
static int ComputeResamplerMode(int in_freq_hz,
int out_freq_hz,
ResamplerMode* mode);
// Generic pointers since we don't know what states we'll need
void* state1_;
void* state2_;
void* state3_;
// Storage if needed
int16_t* in_buffer_;
int16_t* out_buffer_;
size_t in_buffer_size_;
size_t out_buffer_size_;
size_t in_buffer_size_max_;
size_t out_buffer_size_max_;
int my_in_frequency_khz_;
int my_out_frequency_khz_;
ResamplerMode my_mode_;
size_t num_channels_;
// Extra instance for stereo
Resampler* helper_left_;
Resampler* helper_right_;
};
} // namespace webrtc
#endif // COMMON_AUDIO_RESAMPLER_INCLUDE_RESAMPLER_H_
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