webrtc/common_audio/resampler/include/resampler.h

/*
 *  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 WEBRTC_RESAMPLER_RESAMPLER_H_
#define WEBRTC_RESAMPLER_RESAMPLER_H_

#include <stddef.h>

#include "webrtc/typedefs.h"

namespace webrtc {

// All methods return 0 on success and -1 on failure.
class Resampler
{

public:
    Resampler();
    Resampler(int inFreq, int outFreq, int num_channels);
    ~Resampler();

    // Reset all states
    int Reset(int inFreq, int outFreq, int num_channels);

    // Reset all states if any parameter has changed
    int ResetIfNeeded(int inFreq, int outFreq, int num_channels);

    // Resample samplesIn to samplesOut.
    int Push(const int16_t* samplesIn, size_t lengthIn, int16_t* samplesOut,
             size_t maxLen, size_t &outLen);

private:
    enum ResamplerMode
    {
        kResamplerMode1To1,
        kResamplerMode1To2,
        kResamplerMode1To3,
        kResamplerMode1To4,
        kResamplerMode1To6,
        kResamplerMode1To12,
        kResamplerMode2To3,
        kResamplerMode2To11,
        kResamplerMode4To11,
        kResamplerMode8To11,
        kResamplerMode11To16,
        kResamplerMode11To32,
        kResamplerMode2To1,
        kResamplerMode3To1,
        kResamplerMode4To1,
        kResamplerMode6To1,
        kResamplerMode12To1,
        kResamplerMode3To2,
        kResamplerMode11To2,
        kResamplerMode11To4,
        kResamplerMode11To8
    };

    // 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_;
    int num_channels_;

    // Extra instance for stereo
    Resampler* slave_left_;
    Resampler* slave_right_;
};

}  // namespace webrtc

#endif // WEBRTC_RESAMPLER_RESAMPLER_H_