Fast or asynchronous AS3 JPEG encoding

Question

I'm currently using the JPGEncoder from the AS3 core lib to encode a bitmap to JPEG

 var enc:JPGEncoder = new JPGEncoder(90);
 var jpg:ByteArray = enc.encode(bitmap);

Because the bitmap is rather large (3000 x 2000) the encoding takes a long while (about 20 seconds), causing the application to seemingly freeze while encoding. To solve this, I need either:

An asynchronous encoder so I can keep updating the screen (with a progress bar or something) while encoding
An alternative encoder which is simply faster

Is either possible, and how can I do it?

score 6 · Answer 1 · answered Mar 24 '10 at 17:44

6

I found an asynchronous encoder: http://www.switchonthecode.com/tutorials/flex-tutorial-an-asynchronous-jpeg-encoder

answered Mar 24 '10 at 17:44

Bart van Heukelom

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Holy cow! (pun intended) This solution worked awesome for me! – ToddBFisher Apr 03 '12 at 15:27

score 2 · Accepted Answer · edited May 23 '17 at 12:13

2

Setting up the encoder to be asynchronous would likely be your best bet.

Here are two examples from Adobe

This example is with actionscript/flex, but its the same idea.

edited May 23 '17 at 12:13

Community

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answered Mar 24 '10 at 16:59

Jason

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And how do I do that? :) The JPGEncoder has only one method, "encode". – Bart van Heukelom Mar 24 '10 at 17:21
Beat me to it :) I've added a few different examples as well for reference. – Jason Mar 24 '10 at 17:51
You can do it a lot faster now in Flash 10 with Alchemy. – forresto Dec 09 '11 at 11:15

score 1 · Answer 3 · answered Sep 06 '12 at 17:18

You can use the alchemy encoder. It is really fast and you can encode images asynchronously. You can use this class to abstract it.

public class JPGAlchemyEncoder {

    private static var alchemyWrapper:Object;
    private var quality:Number;

    public function JPGAlchemyEncoder(quality:Number) {
        this.quality = quality;
        if (!alchemyWrapper){
            var loader:CLibInit = new CLibInit;
            alchemyWrapper = loader.init();
        }
    }

    public function encode(bitmapData:BitmapData):ByteArray{
        var data: ByteArray = bitmapData.clone().getPixels( bitmapData.rect );
        data.position = 0;
        return alchemyWrapper.write_jpeg_file(data, bitmapData.width, bitmapData.height, 3, 2, quality);
    }

    public function encodeAsync(bitmapData:BitmapData, completeHandler:Function):void{
        var encodedData:ByteArray = new ByteArray();
        var data: ByteArray = bitmapData.clone().getPixels(bitmapData.rect);
        data.position = 0;
        var encodeComplete:Function = function():void{
            completeHandler(encodedData);
        };
        alchemyWrapper.encodeAsync(encodeComplete, data, encodedData, bitmapData.width, bitmapData.height, quality);
    }
}
}

score 1 · Answer 4 · answered Jul 24 '14 at 03:18

asynchronous decode the png picture in separate thread ,supported by new version ...

var loaderContext:LoaderContext = new LoaderContext();
loaderContext.imageDecodingPolicy = ImageDecodingPolicy.ON_LOAD;

var loader:Loader = new Loader();
loader.load(new URLRequest("...png"),loaderContext);
addChild(loader);

that's official.

forresto · Answer 5 · 2011-12-09T11:21:20.090

1

You can do it much faster with Alchemy: http://www.websector.de/blog/2009/06/21/speed-up-jpeg-encoding-using-alchemy/

http://segfaultlabs.com/devlogs/alchemy-asynchronous-jpeg-encoding-2

edited Dec 09 '11 at 11:21

answered Dec 09 '11 at 11:14

forresto

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You should not use Alchemy anymore. This is a deprecated feature as of Flash Player 11.2. – Warren Seine Jan 04 '12 at 13:43
There will be a new version of Alchemy for 11.2+ – forresto Jan 06 '12 at 09:57
But the old code will not work unless recompiled with the new version. – Warren Seine Jan 06 '12 at 20:26
"Starting with Flash Player 11.2 and AIR 3.2, content targeting Flash Player 11 and AIR 3 (i.e., content using SWF version 13 and above) will not support the experimental Alchemy prototype. Existing Alchemy experiments targeting Flash Player 10.x and AIR 2.x are unaffected." http://blogs.adobe.com/flashplayer/2011/09/updates-from-the-lab.html – forresto Jan 14 '12 at 20:09
Yes, that's my point: a .swc compiled with the experimental Alchemy will not work with Flash Player 11.2. You need to recompile your library to make it work with future Flash Players. – Warren Seine Jan 16 '12 at 17:41
not to mention, using Alchemy 2 along with Stage3D, depending on product revenue, may carry some significant licensing fees. http://www.adobe.com/devnet/flashplayer/articles/premium-features.html – ericsoco May 18 '12 at 22:31
1

@WarrenSeine Granted, it isn't good practice this point, but I rest my case that using the old Alchemy and _targeting_ Flash Player 10 still works on Flash Player 11.2+: Screenshot: http://imgur.com/9bWvk Demo: http://meemoo.org/iframework/#gist/2759842 – forresto May 20 '12 at 22:56

Fast or asynchronous AS3 JPEG encoding

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