What vector formats are supported?

EMF, WMF, and SVG work mostly in the same way like a PNG, the vector image turns raster or into image with transparency if you import them directly - through drag and drop into storyline.

For vector, I exported  the EMF, WMF  output made from original software into  PowerPoint, ungrouped them  by converting them as Microsoft drawing object ,they  broke into parts in PowerPoint,  then imported the  PowerPoint file into storyline and again ungrouped them that  converted to individual shapes but distorted them means objects go behind one another. Same treatment to SVG  yielded much better results so in the latest storyline to get a vector image, the following steps could be used.

1) From original vector image containing multiple parts or components in Illustrator or CorelDraw export export as SVG, curves as curves and text as text. Don't  drag this SVG into storyline, it will come in as image, instead, 

2) Import that SVG in PowerPoint, it comes in as graphic, ungroup it into Microsoft drawing object click on it and check whether the vector component are there. If yes,

3) Import PowerPoint in storyline on any slide, ungroup, and all the vector parts are imported intact.