SWF format is now really open...

SWF format has been open since version 3, 1998. It was again May as far I can remember. Now 10 years later, restrictions on using the format is removed, effective as of today, May 1, 2008.

Previous license restrictions were for creating SWF players, creating SWF files was never restricted. I think this was a good idea at the time, nobody wanted multiple incompatible SWF/Flash Players around, also considering the fact that SWF version 3 even had a Java edition player. Now the technology is mature at version 9 - and as I've said 10 years has passed. I personally don't see any danger of multiple browser players gaining ground.

(Another good consequence of this is that you no longer need Adobe Reader to view the SWF specs, Foxit reader now works just fine).

The news came with Adobe Open Screen Project announcement.

Here are relevant links:
SWF Specs at Adobe SWF Tech Center
FLV/F4V Specs at Adobe FLV Tech Center
AMF Specs
ActionScript VM2 Overview (AS3 specs) (PDF)

[F4V is the file extension for HD Flash video, mp4. There's also F4P, F4A and F4B. For playing F4V, Flash player 9.0.115.0 (Flash Player 9 update 3 - MovieStar- released on December 4, 2007) or later is required. Current version of the Player is 9.0.124.0, released on April 8, 2008]