"Coder Charles M Hannum has created the smallest program
capable of decoding a Content Scrambling System (CSS) DVD file,
beating last week's seven-line Perl shell script 442 bytes to 472
(excluding newline bytes)."
"Hannum's C program, called efdtt, is no slouch, either. The
programmer claims it can "descramble in excess of 21.5MBps" -
faster than the DVD spec. allows for. The speed comes "without even
particularly trying to optimise the I/O. This makes it pretty
insignificant compared to the rest of the decoding process" = in
other words, it's quick enough not to impede the MPEG 2 decode
operation which turns the data into a moving image."
"Apparently, the latter may be a problem with qrpff, the Perl
CSS descrambler written by Keith Winstein and Marc Horowitz, and
posted on Carnegie Mellon University professor David Touretzky's
DSS Descrambler Gallery Web site. Winstein and Horowitz' code was
capable of supporting realtime decode and playback, but we're told
the output was occasionally jerky."