Explain details of DVD Blu Ray and HD DVD and including how they manage piracy?

Answer 1

Both of course have their own encoding schemes and encryption mechanisms, much like there are dozens of them used in current DVD technology.

The difference over DVD here is HDMI. This type of output is the future of encryption. If the industry moves in this direction, which probably won't happen anytime soon, you will have to play HD content over HDMI. If an HDMI connection is not found, the title will play in a lower resolution comparable to SDTV or progressive scan (720p). This helps protect the HD content from piracy in that respect.

You can find a ton of info on the net and on Wikipedia.