The claim that pi contains every (finite) sequence of digits is phrased technically as pi is normal. Unfortunately, this is not known to be true. So we don't even know that the deCSS source code is "hidden" in there somewhere.

Note, however, that there is no compression with this scheme. Holding all 10100 100-digit sequences will require at least the first 10100+99 digits of pi (in practice you'll likely need more, as some sequences may be repeated), and so you'll need a >100-digit number as the index to find your chosen number. So it's hard to claim that the index into pi is not an encoding of your program, just like ASCII is an encoding of it.