Digital mass recording devices for video data will enter the consumer marke
t soon. Service providers are reluctant to offer services in digital form b
ecause of their fears for unrestricted duplication and dissemination. There
fore adequate copy protection systems should be developed, most likely base
d on labeling techniques. In this paper we propose two different techniques
for the real-time labeling of digital video. Both methods embed the label
information directly into an MPEG compressed video bitstream, The first met
hod embeds the label by changing variable length codes in the bitstream, Th
e second method discards some of the high frequency DCT-coefficients of the
bitstream to embed the label. The first technique is computationally less
expensive than the second one, however, the second one is more robust again
st attacks to remove the label. We show that the label can still be extract
ed after MPEG re-encoding at a lower bit-rate. (C) 1998 Academic Press.