Thank you for actually putting this up, it has helped me a lot, really.
So the codec is not actually needed to troubleshoot anything then right? And the sdrt4280j.exe I found? It was put beside an IMPORTANT: sign under troubleshooting suggestions for the DRAMAtical Murder VN page. It said that I may need it, but when i looked it up, there were many people questioning it's safety and whatnot which scared me away from it... but fro what it seems like maybe not?
In any case, this is very helpful, so thank you once again.