Just because their authors say that doesn't mean that it's true. Worse still, no corporation is willing to perform a patent search because such an activity could open a liability should it be discovered that something they already use is covered by a patent they previously were unaware of.

The fact is that it is extremely difficult to implement any multimedia application without running afoul of a patent. Rational developers will pick the safest option, and that is to license the MPEG patents, which (I believe) also offers submarine patent protection in that the MPEG-LA would be solely liable for not finding them earlier should trouble arise.

The good news is that these patents are not enforceable worldwide, and the first of them should start expiring (if they haven't already) within the next few years.