Extending the function of a conventional VCR to both do digital recording and to convert analog tape VCR cassette recordings to a digital format without any apparatus modification of the conventional VCR. A portable video recording device comprises a video cassette housing adapted to operatively engage a video cassette recorder, i.e. the VCR requires no modification; the VCR in effect thinks that it is receiving a conventional VCR cassette. The inserted cassette housing comprises a set of read-write heads for operatively engaging an opposing set of read-write heads in the video cassette recorder; disk-drive storage apparatus operatively connected to said cassette read-write heads; and apparatus for converting analog input from the VCR to digital data and storing the data in the disk-drive storage.