I have found that if you render  the video as un uncompressed avi file using firefly, that if acts the same as if you rendered it as a png. It retains alpha transparency which some video editing programs recognize (I use Ulead Video Studio). It saves you having to render each frame individually. Works best with shortish clips or if you have alot of hard drive space.

Daz Studio 4.8 and 4.9beta, Blender 2.78, Sketchup, Poser Pro 2014 Game Dev SR5 on Windows 8 Pro x64. Poser Display Units are inches