func: static inline void downmix_3f_1r_to_mono(float *samples)
  
  {
  
      int i;
  
  
  
      for (i = 0; i < 256; i++) {
  
          samples[i] += (samples[i + 256] + samples[i + 512] + samples[i + 768]);
  
          samples[i + 256] = samples[i + 512] = samples[i + 768] = 0;
  
      }
  
  }
  