Quote Originally Posted by joshstrike
Just caught this...
If you don't know what I mean by a sprite sheet, this is a sprite sheet of Barney the Purple Dinosaur:
http://sousanator.psparchive.de/Spri...ets/barney.PNG
This is the way game designers have been doing animated characters since time immemorial and although there aren't a lot of flash coders who do things this way, there also aren't a lot who do big games with lots of 2D characters...
Thank you for your answer. "Sprite sheets" is a well known technique to me, and I have been a professional game developer for more than a decade now. In fact I already do something similar to avoid multiple http requests, all the individual images are downloaded as one solid file, which I also compress, which saves a huge amount of downloading time as downloading a huge file is faster than downloading 100s of small ones. Unfortunately, the technique does not address the problem stated in the original post.

Perhaps I did not explain the problem in enough detail:

The issue is, I want to achieve compression along the time axis. Basically this means I want to store my animations in a format which only saves the difference between each frame. Individual PNG images, in a sprite sheet or not, does not offer such compression. Typically movie formats are very good at this and achieve significantly smaller files at lossy but high quality (well, depending on the set bitrate).

The ideal scenario would be to compress all frames using a modern MPEG algorithm, which also includes the 8 bit alpha channel, as described in the original post. This is possible using FLV, but the problem is there seem to be no way to extract the individual frames later?

My next thought is to implement my own loader for a movie format, but that surely seem like a lot of wasted energy as there is a fast decoder built into the Flash virtual machine.

To put this into perspective, my game now contains something like 10 megabytes worth of animations after normal compression. Surely too heavy for download, it would kill my server given enough people playing.

Reduced to a proper animation format, the same animations should still look good weighting only a few hundred kilobytes. So, this is my motivation for doing this..