The MiniDisc recorder could be used as stand-alone ADC (analog to digital converter); the digital output should be uncompressed 32, 44.1 or 48 KHz at 20bit... but I must test it to be sure.
Never used VirtualVCR, as my capture card is not supported. Hope VDub has really not dropped any frame, as it would be really tough to scan all frames searching the eventual missing frame!