ProRes is owned and licensed by a small company known as Apple, and Apple competes head to head against Microsoft, so you decode ProRes (play it, encode from it), but you can’t encode ProRes (write to the codec) in Windows, at least not without purchasing an expensive app that includes and expensive license for ProRes.
Your alternative is to install the free Avid DNX codecs, which you can download from the Avid website. The DNXHD codecs are essentially identical to the ProRes codecs, only they work cross-platform, since Avid works on both Macs and Windows machines. Google Avid DNX and you’ll find a chart that will help you to select the proper version of DNX with an alpha channel.
David Roth Weiss
Director/Editor/Colorist
David Weiss Productions
David is a Creative COW contributing editor and a forum host of the Apple Final Cut Pro forum.