SaveFileConverter

SaveFileConverter.com is a website enabling the conversion of save files from many consoles.

Euan Forrester created this tool, and the source code can be found on Github. He hosts this website so you don't need to run it yourself.

In the case of Dreamcast, the tool disaggregates .bin, .vmu, or .flash files, into individual .dci files or a set of .vmi and .vms files, per game save. So basically you can get a single save file off of a whole memory card file.

Conversely, it can build or aggregate a VMU bin file out of multiple individual saves. Using Save File COnverter, you can put combine the save files from multiple different games into a single VMU file.