func: void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
  
      c->bytestream_start=
  
      c->bytestream= buf;
  
      c->bytestream_end= buf + buf_size;
  
  
  
  #if CABAC_BITS == 16
  
      c->low =  (*c->bytestream++)<<18;
  
      c->low+=  (*c->bytestream++)<<10;
  
  #else
  
      c->low =  (*c->bytestream++)<<10;
  
  #endif
  
      c->low+= ((*c->bytestream++)<<2) + 2;
  
      c->range= 0x1FE;
  
  }
  