QuickTime is default, but only get QuickTime movie file icon as thumbnail. No thumbnail preview as you would get with H264 encoded files (or if you were looking at the DXV files in Resolume file browser)
What I can say is that DXV is not the only issue here. DNxHD also uses .mov and Quicktime and will not show thumbnails in Windows Explorer.
Back a few years ago, I remember having to install a PSD codec to show thumbnails for Photoshop PSD files. So it is possible to make a codec decode the file and show the thumbnails in Win Explorer.
So I did some digging and here is what I found. Typical .mov file built in codecs (h264, pjpg, etc) do show thumbnails on my Win 7 & 10 Explorer. Only DXV and DNxHD files seem to have an issue here, but the issue with Thumbnails is only with the Windows Explorer. I get thumbnails for DXV in Resolume's file browser. So I am not really sure Win Explorer thumbnails is needed, unless you drag and drop from Win Explorer into Resolume. In which case I say, why not just use the Resolume file browser? Aside from manually managing your video assets.
You can always look deeper on the DNxHD subject as that codec is a more widely used among other video software and is essentially in the same situation. Perhaps an in depth look at DNxHD will help produce a solution. But ultimately I am not sure it is possible for Win Explorer to use third party codecs though Quicktime, to decode a file and get a thumbnail. That is the main question we should be asking here.
The issue with DNxHD is its developed by Avid to be a QuickTime codec. They don't develop a directshow version of the codec, which is how Windows makes the pretty thumbnails. Probably why DXV doesn't thumbnail properly, no more direct show version (used to be one I believe, you could get avi files before)
Actually my first sentence said that. It was only a means to research how to get thumbnails to show up, because it is more common but in a similar situation to DXV.
