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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 
     12 /*
     13  * A wrapper for resampling a numerous amount of sampling combinations.
     14  */
     15 
     16 #ifndef WEBRTC_RESAMPLER_RESAMPLER_H_
     17 #define WEBRTC_RESAMPLER_RESAMPLER_H_
     18 
     19 #include <stddef.h>
     20 
     21 #include "webrtc/typedefs.h"
     22 
     23 namespace webrtc {
     24 
     25 // All methods return 0 on success and -1 on failure.
     26 class Resampler
     27 {
     28 
     29 public:
     30     Resampler();
     31     Resampler(int inFreq, int outFreq, size_t num_channels);
     32     ~Resampler();
     33 
     34     // Reset all states
     35     int Reset(int inFreq, int outFreq, size_t num_channels);
     36 
     37     // Reset all states if any parameter has changed
     38     int ResetIfNeeded(int inFreq, int outFreq, size_t num_channels);
     39 
     40     // Resample samplesIn to samplesOut.
     41     int Push(const int16_t* samplesIn, size_t lengthIn, int16_t* samplesOut,
     42              size_t maxLen, size_t &outLen);
     43 
     44 private:
     45     enum ResamplerMode
     46     {
     47         kResamplerMode1To1,
     48         kResamplerMode1To2,
     49         kResamplerMode1To3,
     50         kResamplerMode1To4,
     51         kResamplerMode1To6,
     52         kResamplerMode1To12,
     53         kResamplerMode2To3,
     54         kResamplerMode2To11,
     55         kResamplerMode4To11,
     56         kResamplerMode8To11,
     57         kResamplerMode11To16,
     58         kResamplerMode11To32,
     59         kResamplerMode2To1,
     60         kResamplerMode3To1,
     61         kResamplerMode4To1,
     62         kResamplerMode6To1,
     63         kResamplerMode12To1,
     64         kResamplerMode3To2,
     65         kResamplerMode11To2,
     66         kResamplerMode11To4,
     67         kResamplerMode11To8
     68     };
     69 
     70     // Generic pointers since we don't know what states we'll need
     71     void* state1_;
     72     void* state2_;
     73     void* state3_;
     74 
     75     // Storage if needed
     76     int16_t* in_buffer_;
     77     int16_t* out_buffer_;
     78     size_t in_buffer_size_;
     79     size_t out_buffer_size_;
     80     size_t in_buffer_size_max_;
     81     size_t out_buffer_size_max_;
     82 
     83     int my_in_frequency_khz_;
     84     int my_out_frequency_khz_;
     85     ResamplerMode my_mode_;
     86     size_t num_channels_;
     87 
     88     // Extra instance for stereo
     89     Resampler* slave_left_;
     90     Resampler* slave_right_;
     91 };
     92 
     93 }  // namespace webrtc
     94 
     95 #endif // WEBRTC_RESAMPLER_RESAMPLER_H_
     96