Introducing swfversion.com

Posted on Wednesday, October 15, 2008 @ 16:11 CET

Last week I spent way too many hours trying to figure out why this SWF from an agency wasn't working when being used in a client's CMS. Turns out the CMS used another SWF that loaded in all other Flash content. The reason behind this was to show a generic preloader when loading Flash-based content across the board. Fine, makes sense but why doesn't it work?

Sound familiar? Loading SWFs into other SWFs doesn't "just work". Now we have two virtual machines, AVM1 for SWFs upto and including Flash 8, and the awesome, super-fast AVM2 for Flash 9 and above. Loading AVM1 stuff into AVM2 works fine (just don't try talking to it), but AVM2 into AVM1 not so much.

And that's what was going on. After much debugging, decompiling and tearing hair out I decided to check the version and of course that's what was going on. The SWF8 preloader was trying to load in a SWF9 and that was causing all the weird behaviour. So after talking to Chris we figured something had to be done to avoid wasting time on silly things like this in the future.

Enter swfversion.com. You'll need to upgrade to Flash Player 10 first, and then you can load any SWF whether its online or on your local filesystem to find out what version of the Flash Player its targeting, along with what version of ActionScript and frame rate.

Hopefully it will be as useful for the community as the excellent playerversion.com (Aral Balkan's tool for getting at the installed Flash Player info) and James Ward's Is It Flex (to check if that SWF was made in Flex).

As has been my thing lately, you can also use iCanHaz - simply use
http://icanhaz.com/swf/<URL>

Enjoy :)

- paulo

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