"fragmented" mp4 wich is a codec magix cant do.. aparnetly. i find this to be a bit wierd as any other major software can handle them. Works with VLC, Quicktime player, any web viewer... any website when you upload without editing...
and good old magix 2023Platinum cant even open it.
Ian, the difference between the programs you mentioned and Magix is that they are merely players, free, and so don't attract licencing and contain all the common codecs in their own program code. Magix can't do that. Magix can open most common formats but some uncommon ones need to be converted.
What we need is the video codec from your files. Then we will be able to assist with you opening it.
Download and install Mediainfo, and then copy and paste the "Text" view of the readout. That'll give us the info we need to help.