Camcorder capture robust low-complexity watermarking of MPEG-2 bit-streams

Unauthorized re-distribution remains a significant threat for emerging electronic movie distribution services. In this paper, we propose a forensic tracking watermark for MPEG-2 bit-stream that can be employed to complement Digital Rights Management and conditional access systems in electronic movie distribution. The watermark is embedded by modulating a subset of quantization matrix entries, which are periodically present in the MPEG-2 headers. When observed over time the watermark can be detected even after cropping, de-interlacing, resizing and DivX compression at 300 kbps or after being captured with a video camera from a flat-screen TV. As the method modifies only a small part of the bit-stream (approximate to 100 bytes per second), it can be readily implemented in resource constrained environments like the current generation set-top boxes, without costly hardware upgrades.