Alchemy - asynchronous jpeg encoding

9 months ago malczak alchemy comments

Just a quick note, motivated by bytearray.org post about fast jpeg encoding. I am preparing a short talk about Alchemy project and, as an example I have developed an asynchronous JPEG encoder. Encouraged by bytearray.org post I have decided to publish (proof-of-concept) solution.

Encoding JPEG with Alchemy is not only fast, but it also produces smaller JPEG images. Just take a look at the example below. I have used an jpeg encoder taken from bytearray.org.
Optimized JPEGEncoder code and post about it can be found at bytearray.org - http://www.bytearray.org/?p=775.

In demo below we encode 2880x2880 BitmapData, showing the difference in time and size between Alchemy libjpeg port and optimized JPEGEncoder. Right click for flex source code. FlashPlayer 10 required.

When using non asynchronous Alchemy implementation, compression time is much shorter.

But asynchronous implementation is fast enough and can be used particularly in AIR runtime.

Alchemy C code (non optimized, hard coded BitmapData dimensions) is available for download. To compile it You need to recompile libjpeg (http://www.ijg.org/) with Alchemy.

Download Alchemy source file here
Download Alchemy compiled swc library here

For flex source code - right click on application ;)

This is updated version of libjpeg port. You can now compare JPEG encoding times for alchemy asynchronous, alchemy synchronous, bytearray.org, Kyle Lu and buildin mx.* encoders. The difference in the size of a file can also be noted. Right click for code view.

Download jpeg swc library source code, libjpeg ported code with compiled library and swc build script here

Read also post about decoding JPEG images with Alchemy. Used to load bitmap larger than 16MB
http://sflabs.local/devlogs/alchemy-loading-large-jpeg-images