What video viewer(s) allow for frame-by-frame viewing?

In my PDFs, I want to either embed or link to video clips that readers can study one frame at a time (they're short sign language videos where one must look for subtle events). So far the only standard video viewing app with this capability that I know of is Quicktime, but this is now deprecated, requiring lots of time-consuming workarounds on my part. If there's another video viewing app that can accomplish frame-by-frame viewing, my life would be easier since I could just tell my readers to make that the default for MP4s (although presumably I'd have to link to it in PDFs instead of embedding it). Thanks.