apps/codecs/libgme/resampler.h

   1 // Combination of Downsampler and Blip_Buffer mixing. Used by Sega FM emulators.
   2
   3 // Game_Music_Emu 0.5.5
   4 #ifndef RESAMPLER_H
   5 #define RESAMPLER_H
   6
   7 #include "blargg_config.h"
   8 #include "multi_buffer.h"
   9
  10 typedef short dsample_t;
  11
  12 enum { stereo = 2 };
  13 enum { max_buf_size = 3960 };
  14 enum { max_resampler_size = 5942 };
  15 enum { write_offset = 8 * stereo };
  16 enum { gain_bits = 14 };
  17
  18 struct Resampler {
  19         int (*callback)( void*, blip_time_t, int, dsample_t* );
  20         void* callback_data;
  21
  22         dsample_t sample_buf [max_buf_size];
  23         int sample_buf_size;
  24         int oversamples_per_frame;
  25         int buf_pos;
  26         int resampler_size;
  27         int gain_;
  28
  29         // Internal resampler
  30         dsample_t buf [max_resampler_size];
  31         int buffer_size;
  32
  33         int write_pos;
  34         double rate_;
  35
  36         int pos;
  37         int step;
  38 };
  39
  40 static inline void Resampler_init( struct Resampler* this )
  41 {
  42         this->pos = 0;
  43         this->write_pos = 0;
  44         this->rate_     = 0;
  45 }
  46
  47 blargg_err_t Resampler_reset( struct Resampler* this, int max_pairs );
  48 void Resampler_resize( struct Resampler* this, int pairs_per_frame );
  49
  50 void Resampler_play( struct Resampler* this, long count, dsample_t* out, struct Stereo_Buffer* ) ICODE_ATTR;
  51
  52 static inline void Resampler_set_callback(struct Resampler* this, int (*func)( void*, blip_time_t, int, dsample_t* ), void* user_data )
  53 {
  54         this->callback = func;
  55         this->callback_data = user_data;
  56 }
  57
  58 blargg_err_t Resampler_setup( struct Resampler* this, double oversample, double rolloff, double gain );
  59
  60 static inline void Resampler_clear( struct Resampler* this )
  61 {
  62         this->buf_pos = this->sample_buf_size;
  63
  64         this->pos = 0;
  65         this->write_pos = 0;
  66 }
  67
  68 #endif