Yahoo! Flash (R) Blog

Yes, Virginia, There is Compression in Flash

I’m in the process of developing a new hybrid component–a component which utilizes the Flash Player but via a JavaScript API–for YUI. This new component will take advantage of Flash’s native SharedObject functionality to store local data in a larger amount than is typically allowed by a cookie. By default this storage is up to 100kb. However, I found a way to store nearly half a megabyte in this space.

No, I did not have to request the user to allow 512kb of storage on their machine. And there was no magic or hackery involved. That’s because the space I took up on the hard drive was less than 100kb. I just took advantage of a little known feature in the Flash Player, allowing compression of data.
This feature is quietly tucked away inside of the ByteArray class–ByteArray.compress() and ByteArray.decompress().

Taking what was a half meg of JSON data over-the-wire and putting it into a SharedObject (which stores in binary) resulted in a huge savings already, about 60%. But compressing that data before storage resulted in a total of 80% savings.

I’ve still got some performance testing to do, as for all compression one must sacrifice processor cycles for storage space. But I feel pretty confident this will remain in the release version. So, either take this idea and run with it, or wait a bit for the next YUI release.

By the way, I also recently posted an article on the YUI Blog entitled Flash SOL: Persistent Data with Local SharedObjects. Thought I’d share it with you all, if you didn’t see it.

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