RoQ Cinematics from original Doom 3 now work in Doom 3 BFG!! You need to extract the Doom 3 cinematics into the matching folder in your Doom 3 BFG install. Missing cinematics now show up as white. Some issues: Your boss has the old hairstyle in cinematics, BFG expects a new cinematic for rotating Mars in the title, which now shows as white. RoQ cinematics are in a few different PAK files, so check them all.
I started adding FFMPEG32 for Bink cinematics, but couldn't get it to work. Let me know if you have any luck.