That is not correct. I own a 16-bit ISA MPEG 1 decoder card (2themax MPEG Wonder) that has two VGA connectors and connects just like a Voodoo. Also, all later MPEG2/DVD decoder cards for PCI from RealMagic, Creative Labs etc. are connected externally as well (though they use custom cables).I'm almost 100% certain it's a Voodoo1/2. MPEG decoder cards usually had no output, they connected to the main video card through the VESA feature connector internally with a ribbon cable.
That is not correct. I own a 16-bit ISA MPEG 1 decoder card (2themax MPEG Wonder) that has two VGA connectors and connects just like a Voodoo. Also, all later MPEG2/DVD decoder cards for PCI from RealMagic, Creative Labs etc. are connected externally as well (though they use custom cables).